# Varible Power Supply



## cwbam (Feb 8, 2010)

Has anyone tried a Notebook computer charger as a power
supply?
Or for around 18 volts an old Nintendo Game Cube dc power
chord?
I saw this Cable Unlimited 100w power adapter with its with its 15v-24v range, & thought that may work.


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## SwamperGene (Dec 1, 2003)

Laptop power bricks make great power supplies. :thumbsup:


Anything that'll give you a few amps of clean power is better than a stock wall wart.


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## tasman (Feb 17, 2007)

*Enough amps?*

from their website...
Compact design makes it an ideal AC power at home, the office or on the road 7 adjustable output voltages DC 15V, 16V, 18V, 19V at 5.5A Max. 20V, 22V, 24V and 4.5A max 

Question....
I'm running Tjets, Magnatractions, and AW equivilents - plus some older Tycos and Tomy up to their SRTs. No modifieds or wizzards etc.

Is this enough amps for both lanes with 1 power supply? I don't want to get a surge when the other lane deslots? (I'm currently running 1 wall wart per lane)

Thanks.


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## AfxToo (Aug 29, 2003)

According to the spec sheet:

7 adjustable output voltages:
DC 15V, 16V, 18V, 19V at 5.5A Max. 
20V, 22V, 24V and 4.5A max

You should have no problems at all running anything up to and including superstock cars (Wizzard Storm, BSRT G3/G3R, Slottech T2/3, etc.) even with hot stock motors and slammed setups for your 2-lane setup. This would even work well for 4-lane setup. No problem.

This looks like a very nice upgrade from stock wall warts. You're going from a 7 watt supply per lane to a 100 watt supply for both! That's a huge improvement. If the range of available voltages went down into the 10V-12V range this would be even more attractive. The only minor concern I would have is that the switch does not look like it is something that is designed for many thousands of switching cycles. It looks like something you set for a specific application and leave alone. I can't imagine you'll run into any issues here, but it is a potential weak point.


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## NTxSlotCars (May 27, 2008)

Wow, that looks like a great option CW!!
Where do you get something like that, and what price range?


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## Rolls (Jan 1, 2010)

I looked at those pretty closely as an option when I finally ditched the wallwarts. I found a pretty neat switchable universal laptop supply that could put out 3A or so continuously and maybe 7A burst. It's output voltage was switch selectable in a handful of stops between 12 and 24V as I recall. Most important, it was very well regulated. For about $65 shipped, it was attractive. And I could double or even quadruple them in the future if desired. No meters, though. (I can't find the link to this unit now - sorry.) 

I think these can be a terrific upgrade for your track.


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## Dslot (Sep 2, 2007)

The TM has had an old Dell Laptop for some years, and it uses this P.O.S. adapter (20V 3.5A DC), which she has replaced several times:










The permanently-attached low-voltage cord on this thing always fails, ripping itself out of the input plug at the computer end, apparently from the weight of that cylindrical gizmo flopping around a few inches out. I've fixed, reinforced and refixed them, but they always end up disintegrating, so I have two of them, sans plug, stacked in the junk-transformer box (and I've already recycled a third one). 

To use them for slots, should I keep the cylindrical gizmo on the line, or cut it off? It looks suspiciously like a big, rubber-armored capacitor, so would I be losing the beneficial current filtration if I ditch it?

(Actually, whatever it does, I think its main design purpose is to flop the cord around so Dell can keep selling you power bricks.  Is there any real reason it has to be next to the input plug instead of down in the brick? My Mac doesn't have one on the cord.)

-- D


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## cwbam (Feb 8, 2010)

Fry's had it on sale, but I was to late or they had very few in stock.
newegg has them for : $49.99 $6.98 Shipping
I've seen lots of used power supplies at thrift stores, I'm curious about Nintendo game cubes 18v.

I would test any supply with test meter (cheapo from harbor freight) then cut the chord (leave some room , if you want to splice it back & maybe color code it) then splice a new line in.

Extra power supply chords are great (TOMY TYCO LifeLike)
if they burn out cut and keep the chord.


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## AfxToo (Aug 29, 2003)

> should I keep the cylindrical gizmo on the line, or cut it off? It looks suspiciously like a big, rubber-armored capacitor, so would I be losing the beneficial current filtration if I ditch it?


The gizmo is an external EMI filter (electromagnetic interference) that takes out the very high frequency artifacts that are a consequence of the switch-mode power supply design. These frequencies are in the RF region and will have no affect on the health or performance of your slot cars but may interfere with over the air devices like radio, TV, and wireless communications. In this case the manufacturer is mostly concerned about interference with the PC itself. Some power supplies have the EMI filter built into the power supply while others have some EMI filtering internally and some externally. You'll see these filters on other device cables like those used for analog monitors. These gizmos are required by the FCC and manufacturers must comply. 

So to answer your question, no you would not lose any of the benefits of the regulation and current filtering that is the primary concern for the AC to DC power conversion. You may be creating some extraneous EMI that has other unintended side effects outside of the your slot car concerns. But then again, the slot cars themselves are creating plenty of EMI all on their own and most modern electronic devices are not nearly as susceptible to EMI as they once were.



> Is there any real reason it has to be next to the input plug instead of down in the brick? My Mac doesn't have one on the cord.)


I suspect that the EMI filter is placed as close to the PC as possible so that any additional EMI induced through the wire leading up to the power connector on the PC is also knocked down by the EMI filter. On the Mac they must do the EMI filtering in the power supply itself.


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## Dslot (Sep 2, 2007)

Thanks, AFXtoo. :wave: 
You can always be counted on for solid info.
-- D


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## tasman (Feb 17, 2007)

*Thanks also*



Dslot said:


> Thanks, AFXtoo. :wave:
> You can always be counted on for solid info.
> -- D


Yes, Thanks also for the response to my question!


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## northwest slot (Dec 1, 2009)

cwbam said:


> Has anyone tried a Notebook computer charger as a power
> supply?
> Or for around 18 volts an old Nintendo Game Cube dc power
> chord?
> I saw this Cable Unlimited 100w power adapter with its with its 15v-24v range, & thought that may work.


Watch the amperage on those devices. They will likely be rated in milliamps (not enough juice). Some of the notebook power supplies have adequate voltage and amperage. 

The problem with the notebook power supply is changing the voltage if you want to run cars at 12 volts. 12 volt power supplies are easier to find, so you could just wire two systems that can be flipped with a switch.

On a six lane track with superstocks, you might clip 10 amps.


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## bondoman2k (Jan 13, 2003)

Hi guys. I don't usually post on here, do a lot of 'lurking'. Registered here back when I was customiuzing diecast stuff (Gunn knows me over there..lol..not sure who else does). Got into HO drags about 2 years ago, but watch for me to post more often, as I am in the middle of building a 1/8 scale dragstrip in my spare bedroom, and will have pics pretty soon. Also , now that I've figured out the new camera (was my wife's but she recently passed away, so it's now mine), I will start getting pics of my drag cars too. I also 'play around' with some resin casting, and have some "interesting" drag bodies too.
I just got one of these laptop chargers on Ebay for 35 bux plus shipping. Got it in 3 days after the auction ended! SUPERFAST shipping! Anyway, the one I got has a button on the front to switch the voltage, so it can be changed anytime. This one is rated at 12, 14, 16, 18, 19 and 20 v at 4.5 amps. Also can be switched to 22 or 24 volts at 4 amps. And that is Amps, not MA (milliamps). That may or may not be the 'actual' voltage when it gets to the track, but it shouldn't lose that much voltage should it? 
Haven't hooked it up yet, as my track is still in the 'construction' stage, but I think this should do great for just 2 lanes! Whatcha think guys? Will be mostly Tjets or Tjet based cars, but may occasionally run a few inlines.
Ron (Bondo)


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## Rolls (Jan 1, 2010)

That's sounds like a great fit for your intended purposes, Ron. Might be good to add a small capacitor between your black and red terminals at your driver's stations to knock down any AC-ripple that the brick might pass through. Cheap and easy.


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## 440s-4ever (Feb 23, 2010)

Is the ripple concern because it's switchable, and may do funky things during the switching?

Thinking hard about trying it myself, as we add older styles of chassis to the 440x2 fleet, the need for lower voltages is becoming obvious. Dealing with dual wall warts and seperated terminal tracks is a pain, this looks like a super convenient solution.


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## Rolls (Jan 1, 2010)

I think the computer power supplies are a great idea and I'm excited for the overall experience base of users to grow -- it'll benefit everyone. 

The cap is absolutely optional, but it is super cheap and easy with basically all upside and no downside.

There's really 3 things that make me suggest it for a brick especially, though it's still a good idea for any power supply.


You nailed it - the bricks are always switching power supplies and the switching frequency can show up on the output as ripple in normal operating conditions. (Note that this is switching as in how it converts AC to DC, not to be confused with switching as in the output can be changed to different voltages by a switch.)


The designers might well find a larger amount of 60Hz ripple acceptable for a brick. The AC wall frequency can also sneak through in small amounts to the output of any supply, but designers might not care as much for a supply that charges a battery in a laptop compared to one used in the lab for sensitive equipment.


Bricks are small. Even if the cost budget might allow for a high ROI addition of a cap for the output, the size constraints often preclude it's usage - so they leave it out.

So those are the reasons why I'd especially recommend a cap at the driver's station for a brick. But really, since DC motors like the ones our awesome little cars use just don't like AC ripple, and caps are super easy to install and cheap to buy, it's a good idea for anyone using any type of power supply. 

BTW, I particularly like the placement of the cap between the controller's output and ground as opposed to putting it between the supply's output power and ground, which at first might seem the obvious placement. The additional resistance of the controller provides the R in the RC filter - it gives the cap something "work against" (or makes it a better voltage divider, if that makes more sense) and helps the cap minimize the ripple much more effectively. It also puts the filtering effect of the cap "closer" to the power consumer, the car's motor. So for placement of the cap, it's not even a tradeoff - it just plain better to put it after the controller!

Last, I'll add one more reason I think bricks are a good match for tracks... They can typically provide high levels of peak current compared to their rated steady-state current output. This is again because of packaging constraints. It's hard for them to dissipate the power (heat) that the high current operation generates. In a lab supply, you just add a big old heat sink and slap on a fan too, if you like. Can't do that in a brick. So a brick can only deliver the higher currents (that it's components can actually handle) in short bursts. 

But that's just how our cars use it - in bursts. Most layouts don't let you give the car full throttle for 30 secs at a time - and usually much less than that. The highest current drawing cars are the fastest, so again, it works in our favor - the high current bursts are even shorter because the current sucking cars are so darn fast in the straights.

Sorry for the long post. Hope it helps.


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## AfxToo (Aug 29, 2003)

Ripple is largely a red herring with slot cars. The negative effects of ripple are negligible to imperceptible to a slot car motor. Keep in mind that early slot car sets came with half wave rectified power supplies AND that some modern controllers use PWM to control motor speed. You can't get much worse from a noisy power supply perspective than pulsed output. You also cannot ignore the natural "ripple" that is induced through the commutation process in a brushed motor. Does ripple cause a loss in efficiency? Yes, but it's nothing compared to a bad mesh on a gear or a bad bearing surface. Trust me, the sensitivity that a modern computer has to AC ripple is much greater than that of a toy slot car motor. I have zero concerns with AC ripple from a laptop power supply having an impact on a slot car motor. By the way, with a switching power supply we're talking kHz or MHz ripple, not 60 Hz artifacts.


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## alpink (Aug 22, 2010)

very, very ... interesting!


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## Hornet (Dec 1, 2005)

Rolls,you're good at theory,how about some real world advice.
You tell eveybody you're ideas,but no explanation on how to impliment them.
Some guys here have never worked with cap's,so you better tell them how you're installing a cap,just don't say "put a cap in place",you need an explanation on how.
And also some sort of warning about how dangerous a charged cap can be.
There are a few of the younger generation reading these posts,so be careful what you reconmend:thumbsup:


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## alpink (Aug 22, 2010)

on the drag strips I have built, 1/24 and 1/64, I place capacitors at every power tap between the negative and positive leads for each lane. I would think that a circuit track would use similar applications with additional capacitors at each controller station. drag strips don't have brakes for the controllers to hook to, so there is no application there. circuit breakers or fuses are highly recommended to save valuable equipment and track from accidents.


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## AfxToo (Aug 29, 2003)

Drag racing is another story altogether. 

The primary benefit that large capacitors have on a drag track is to prevent voltage sag when you initially pull the trigger and early in the launch cycle - which is a significant portion of the total race! While the slot car's motor is stopped and just starting to spin up it generates none and then very little back EMF, so the current demand on the power supply is simply the power supply voltage divided by the resistance in the circuit. With a low resistance motor winding, say 1 ohm and neglecting wiring and rail losses, the initial current demand would be 24 amps if you're running with a 24 volt power supply. This peak demand only lasts a few milliseconds, but even with a regulated power supply this peak current demand can cause a temporary (milliseconds) drop or sag in the output voltage. 

Since every millisecond counts in drag racing any voltage sag has a detrimental effect on the race. This assumes the power supply can handle the peak current demand. If the peak current output of the power supply is less than what the car is asking for, and especially if the motor resistance is less than an ohm, it's very likely that the power supply will see this current demand as a short circuit and it may temporarily (in milliseconds) engage over current protection circuitry which will typically involve dropping the output voltage towards zero volts. You can imagine what effect this has on performance, it's like cutting the fuel off to a gasoline motor for a few milliseconds when the fuel demand is at its peak. Again, in drag racing every millisecond counts!

So what purpose do the large capacitors serve in a drag track? Capacitors store or release energy based on differences in voltage. When the voltage applied to a capacitor is greater than the voltage charge in the capacitor the capacitor will "charge" up to the applied voltage. If the voltage applied to a capacitor is equal to the voltage charge in the capacitor it will do nothing except maintain its charge. If the voltage charge in a capacitor is greater than the voltage applied to the capacitor the capacitor will "discharge" and supply voltage to its terminals. In the previous scenario, when the current demand hits a peak and the power supply voltage starts to sag the capacitor will discharge and fill-in the voltage that the power supply would otherwise have dropped. 

The capacitor only has to fill-in for those few milliseconds where the current demand is at its peak. Once the slot car's motor is spinning the current demand drops considerably, the power supply recovers, and the capacitor recharges so it is ready to fill in again as needed. In general capacitors can only fill-in for very brief gaps unless the current demand is very low. 

Again, because drag races are decided by milliseconds and the duration of the launch and spin-up is such a large proportion of the race duration, every millisecond counts so having large capacitors for drag racing makes a lot of sense. For roundy round racing, this is less of a concern unless your power supply is not quite up to snuff and is running into cut-off problems that are affecting the racing action. But none of these issues have anything to do with AC ripple, which is a very low concern. 

Incidentally this application of large capacitors is known as "stiffening" or "voltage stiffening" and is very common practice for high power automotive audio applications to extend the service life of the car's battery and alternator.


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## slotcarman12078 (Oct 3, 2008)

I have a very limited knowledge of capacitors, but I will throw these little bits of info I've read out here, and you smarter guys can give your take on them. First off, some capacitors are polarized, meaning there is a positive and a negative leg to them. Depending on the type of cap, some can pop if hooked up the wrong way, and the stuff in them is not very friendly. Also, as stated, they store energy. I'm not sure how much they can store, but I recall a friend of mine telling me he made a home made taser out of disposable camera parts. He may have been pulling my leg on that one... I have heard the larger caps can knock you on your butt if you happen to be the object they discharge into. I would choose carefully which type of capacitor you use on a track. Roundy round tracks that can run in both directions should not have a polarized cap!


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## 440s-4ever (Feb 23, 2010)

Great thread, lot of quality info here. My 2 cents as a long time DC guy thru automotive and factory applications....

The ripple effect is real but as a carpet racer am not that concerned with it. The contacts and brushes in a slot car & controller are fairly robust and can certainly handle a lot more than we throw at them. There are probably exceptions like the tyco U turns with simple circuit boards, but again those don't concern me as you're probably not switching power with the trigger pulled anyway. 

I could understand capacitors with league type drag racing or 1/24 cars, but for tiny little HO motors and people just having fun with toy cars, a modern power supply wired direct should be a quantum improvement. As we see from the cost of a quality power supply, slot car manufacturers have to go cheap to keep sets priced like toys. 

Fuses or breakers are a good idea, but the power supply ought to have an internal breaker. If it's got a manual reset button there ya go, but many are self-resetting just unplug and let it cool off a bit. 

Thanks again to everyone, I'm off to shake my friends down for a cord from a dead laptop. Plan B is to hit a couple permanent flea market stores, those places are full of dead electronics and have got to have a basket full of power supplies.


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## Rolls (Jan 1, 2010)

AfxToo said:


> Ripple is largely a red herring with slot cars. The negative effects of ripple are negligible to imperceptible to a slot car motor. Keep in mind that early slot car sets came with half wave rectified power supplies AND that some modern controllers use PWM to control motor speed. You can't get much worse from a noisy power supply perspective than pulsed output. Does ripple cause a loss in efficiency? Yes, but it's nothing compared to a bad mesh on a gear or a bad bearing surface.


I agree. But I don't see where I assigned any exaggerated importance to idea of supplying DC power to a DC motor. 



AfxToo said:


> You also cannot ignore the natural "ripple" that is induced through the commutation process in a brushed motor.


When you serve clean DC power to a brushed motor, the commutation process does ugly things with it and thereby to it. I don't ignore it. In fact, adding a filter cap actually helps attenuate the EMI the motor puts out on the rail. While this is a benefit, I don't call it out because most modern equipment is so well protected from it that it only occasionally matters.



AfxToo said:


> Trust me, the sensitivity that a modern computer has to AC ripple is much greater than that of a toy slot car motor.


This is a fact but it is misleading here. No modern computer relies on it's external brick for the quality of power of its circuitry. For that the computer internally filters and regulates the power to clean it up. If you try to run your computer on it's brick and bypass all the internal clean-up circuitry that would be a very bad idea.



AfxToo said:


> I have zero concerns with AC ripple from a laptop power supply having an impact on a slot car motor.


I'm not overly concerned by it either, though many swear by using battery power and report much better life from their pickups and cleaner rails. I'm not sure why this would be, but I haven't done any tests one way or the other. 



AfxToo said:


> By the way, with a switching power supply we're talking kHz or MHz ripple, not 60 Hz artifacts.


Again, I'm not sure what this referring to... The switch-mode artifacts imposed on the output are covered in a separate paragraph from the 60Hz artifacts. They're even numbered 1 and 2. There isn't any mixing of them at all.


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## Rolls (Jan 1, 2010)

Hornet said:


> Rolls,you're good at theory,


Thanks, Hornet. I'm OK at theory, but you should hear me with something I'm really great at, like fart jokes.



Hornet said:


> how about some real world advice.


Careful what you ask for... Sure you don't want fart jokes?



Hornet said:


> You tell eveybody you're ideas,


Sorry about that.



Hornet said:


> but no explanation on how to impliment them.


Well, you got me there. I didn't want to go into too much detail (though I probably did), because all I was saying about adding a small cap to the DS while your soldering iron is out if you do care about getting back some of what your tidily packaged supply might give up is "adding a small cap is optional, but it's cheap and easy and basically all upside." 

I now recognize that this capacitor issue is a charged one, but still, let's not get our Coulombs all in a bunch now.



Hornet said:


> Some guys here have never worked with cap's,so you better tell them how you're installing a cap,just don't say "put a cap in place",you need an explanation on how.


It's a mixed group, though. Some guys have never worked with caps, some have but resisted learning about them, and still others use all caps for some of their posts - a tough audience. I, for example, pride myself on having developed an expertise that far exceeds my knowledge. But enough about me, let's talk about what you said about me. Hmmm... as far as how to impliment, you're right. I only suggested which two terminals to hook the two ends of the cap to, but I didn't specify cap size, type, or color. Feel free to add if you have a recommendation or ask if you want an opinion. Or a fart joke.



Hornet said:


> And also some sort of warning about how dangerous a charged cap can be.
> There are a few of the younger generation reading these posts,


I thought about this for a long, long, time, but after much consideration, I left this type of warning out, because, well, a .1uF cap charged up to 18V is not dangerous, even for the young at heart. I wouldn't eat one or stick one in my eye, though. Of course that's only my opinion and I am not an attorney (I don't mean to brag).



Hornet said:


> so be careful what you reconmend:thumbsup:


Ok, now THAT is something I wish you told me BEFORE I posted. It is exceptionally good and timely advice that I will take to heart.

P.S. (heart rhymes with fart, btw).


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## alpink (Aug 22, 2010)

all very good information, the capacitors I have installed, at the suggestion (almost insistance) of the manufacturer, John Sojak, of the Trik Trak Drag Trax drag timing system were for the purpose of helping eliminate glitchs in the timing system caused by whatever spark causes, be it EMF, RF or whatever it is properly called. when new, these timing systems came with enough capacitors to use every 4 feet on a 1/24 scale drag strip of 55 powered feet. I simply took some to Radio Shack and bought more of the same as I built tracks for other people. I am not so very technical as to know exactly why they help, but there are fewer glitches when used properly than when not.


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## Dyno (Jan 26, 2009)

I have been using Sony laptop power supplies on my track for 2 years now. They are rated at 19.6 volts and 4.5 amps. I have one for each lane. Previously, I tried a few other brands before the Sony's, and some of them would suddenly shut off without warning. When I unplugged them for a minute or two and plugged them back in they would work again, but that was quite annoying. I have never had that issue with these Sonys.


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## Dslot (Sep 2, 2007)

*Pop Prevention*



slotcarman12078 said:


> Roundy round tracks that can run in both directions should not have a polarized cap!


Well, they _can_ have, but the capacitor needs to be between the power supply and the reversing switch. After I determine which terminal is positive, I attach the capacitor directly across the terminals of the old Aurora packs. If the pack has a built-in reversing switch, forget the capacitor unless you're willing to disable the switch.

And yes, they can 'pop' if hooked up to the wrong polarity, but 'pop' doesn't do it justice - somewhere between a cherry bomb and a .22, I'd say. Been there, done that, and nearly jumped out of my skin. :freak:

-- D


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## slotcarman12078 (Oct 3, 2008)

LOL.. You had one of them electrolytic filled ones!! As bad as mattel tires I hear!! :tongue: I'm a chicken when if it come to caps. If someone I semi trust tells me something bad about them I tend to go over protective, but better safe than sorry. What I would like to know is what are the different properties of different types of caps? Ceramic disc, electrolytic, etc.. what purposes and differences do they provide. Which has better performance for doing something like stabilizing flickering LEDs due to goofy tires and track joints.. ? Which ones make for better fart jokes?


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## NTxSlotCars (May 27, 2008)

I just use pallet jack/golf cart batteries.
I charge em like once every 6 months.
Plenty of amps, no voltage drops.


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## Hornet (Dec 1, 2005)

Rolls,what happens with the guy who puts 24 volts into a 16 or 18 volt cap.
Ever see a cap let go,i know a guy missing a finger from one,that's why you gotta be careful on what you reconmend.
Not bashing your idea,as it has merit,just trying to warn you:thumbsup:


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## SwamperGene (Dec 1, 2003)

The real question would simply be has anyone put in caps and documented a significant improvement in lap times, driveability....anything?

:freak:


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## AfxToo (Aug 29, 2003)

> were for the purpose of helping eliminate glitchs in the timing system


Yes, small unpolarized ceramic capacitors are often used to reduce high frequency glitches or RF noise across transmission lines, which in our case are the track rails. You can generally tell the purpose of a capacitor based on its value and physical size. In general larger value capacitors are in larger physical packages. Typically, the larger the capacitor the lower the frequency it is designed to work with. If you look inside a large linear power supply like the MG Series (sold by Galinko) you'll see some very large capacitors because they are there to remove low frequency (50 Hz or 60 Hz artifacts) ripple from the rectified (AC converted to DC) output. When you see smaller caps like the ones mounted on European slot cars you can tell they are there to remove high frequency noise. Big cap = low frequency, small cap = high frequency. 

This size factor also explains the main difference between a linear power supply (Galinko and many others) and switch mode power supply (most wall warts, laptop power brick, etc.). Linear power supplies perform the AC-to-DC conversion and primary filtering at the wall/mains frequency (50 Hz or 60 Hz) so all of the components are very large and very heavy. A switch mode power supply first converts the wall/mains frequency to a very high frequency and does the AC-to-DC conversion and primary filtering at high frequencies, so much smaller and lighter components can be used. The issue of course is that a switch mode power supply is also creating high frequency noise that must be cleaned up after the fact, which is why these power supplies have a reputation as being noisier. But most high quality modern switch mode power supplies are pretty darn good at cleaning up all the high frequency noise and are perfectly fine for all but the most demanding applications. Running slot cars is not a demanding application.

So why the small filter caps along your track? Because the sparking process produces electromagnetic signals across a very broad range of frequencies, including radio frequencies (RF) that interfere with other electronic equipment. In fact, old time radar and radio jammers were based on spark gap generators/amplifiers. Sparks produce electromagnetic noise. By placing the capacitors across the track rails some of the electromagnetic noise generated from the sparking at the pickup shoes and commutator is short circuited to ground through the filter caps.


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## AfxToo (Aug 29, 2003)

> he real question would simply be has anyone put in caps and documented a significant improvement in lap times, driveability....anything?


I'd be shocked to see any recognizable performance benefits from filter caps, but a stiffening cap on an unlimited drag car race setup would probably be noticeable because of the race durations are so short. Maybe one of the HODRA guys can chime in with data. I recall seeing one of those guys that had a big stiffening cap setup mounted in a metal toolbox that was used for drag racing events. 

SwamperGene, I do hear you though. While the theory behind these topics is interesting there is little practical implications on 99.99% of the slot car population. I simply don't worry about any of these things with slot cars because they are not sensitive and sophisticated electronic components, they are toys designed to nondiscriminating tolerances for kids like us to beat up on.


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## Dslot (Sep 2, 2007)

SwamperGene said:


> The real question would simply be has anyone put in caps and documented a significant improvement in lap times, driveability....anything?


Yes (if my 20-yr. old memory counts as documentation). 

Most of my life, my main hobby was model trains. About 1990, I grabbed the garage-sale slotcar stuff out of the storage warehouse and set up a fairly large 2-lane in the apartment living room for a couple of weeks. In testing the track, I was troubled by how hot the Tjets got.

One of the tips I'd saved from *Model Railroader* magazine many years before was to put a 35-V 470-microfarad capacitor across the powerpack terminals to make the locomotive motors run cooler; so I tried it and made some tests, running a set number of laps and testing the motor temp by feel. At the time, I concluded the capacitor made a difference, but I don't have any numerical measurements to back that up. I wasn't concerned with lap times, just saving the chassis from meltdown.

I stuck with that setup until 2008 when *AFXtoo* suggested I use a much bigger capacitor (4700 µF). I took his advice, but haven't made any tests to confirm further improvement.

-- D


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## AfxToo (Aug 29, 2003)

Yes Dslot, the 4700 uF is much better for ripple filtering. It cannot have a negative effect but I would be very interested to see what the temperature readings are with a heat gun before and after the addition of the filter cap. My assumption is that the difference on a slot car motor would be quite small, just a few percent. Who knows, perhaps due to the greater current requirements on a TJet (or model train) the difference would be even greater and should not be ignored. It is a fact that AC ripple causes motor heating and excessive brush wear on large industrial DC motors, but tiny slot car motors?


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## 440s-4ever (Feb 23, 2010)

Define excessive brush wear. Industrial application you're talking about motors that run for huge time periods. I bet slot car brushes barely make a hundred hours, you'd have to have brushes tall enough to stick out the side of the car when new to make them last for 500 hours. If an industrial motor consumes brushes at 500 hours something is very wrong. 

So maybe our norm is excessive? Never really thought about it before

Interesting conversation!


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## Dslot (Sep 2, 2007)

.


> ... My assumption is that the difference on a slot car motor would be quite small, just a few percent...


And you may well be correct, *AfxToo*. 

My alleged evidence for improvement is about as bad as evidence can get - 
A twenty-year old recollection of a 
hastily-done,
uncontrolled, 
unrepeated experiment,
performed by an inexperienced amateur 
judging by totally subjective means ("this sorta feels like it might be a little cooler than when I felt it three minutes ago"), 
and highly subject to confirmation bias (I'd already bought the capacitors, and I was hoping they would help, so there's a possible upside and no downside to convincing myself they were effective).
The skeptic in me is rolling on the floor, howling. If it weren't all we have as evidence (so far), it would hardly be worth politely pretending to consider.



> ...I would be very interested to see what the temperature readings are with a heat gun before and after the addition of the filter cap.


I wish I could oblige, but I don't have one of those remote thermometer things [Where is Mr. Spock when you need him: "Captain, the tricorder indicates a 3.7% reduction in infrared radiation in the neighborhood of the lower bearing."]. Surely someone has one, and can perform the test in a more scientific way. A decent first-test protocol might be:

Run laps for five minutes to get the car at running temperature,
Take a one-minute break to let the car cool, 
Measure the car temperature [T1]. 
Run ten laps on straight DC and measure the car temperature at the end [T2]. 
Add the capacitor to the circuit, and monitor the car temp. as it cools. 
When it drops to T1, run ten laps on capacitor-filtered DC, and measure the car temperature at the end. [T3].
Compare T2 and T3, and look happy or sad.
Any volunteers?

-- D


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## AfxToo (Aug 29, 2003)

Yes, industrial motor brushes should be expected to last thousands of hours even in high current scenarios. Slot car brushes, under continuous use and when adjusted properly, hard to say precisely but I'd expect them to last from 4 to 12 hours or so. I've run new Tomy endbells for more than the entire duration of 8 hour enduro races, but other than that I don't have a lot of cumulative data. I have seen brushes wear out much more quickly due to misadjustment or misalignment but what other effects which may have contributed is somewhat of a mystery. 

I do know that there are factors that affect the larger scale machinery that definitely transfer down to our micro machinery. The physics is still the same but the scale is not. However to what degree these effects happen and what the impact really is may not be significant because of the scale and purpose of the different machines. Also, when racing is involved we tend to sacrifice longevity for shear performance. How many times have you seen an hourglass shaped comm on an inline motor with not a lot of race time on it due to the brushes being driven into it a little too hard. When I see an hourglassed arm or one that looks like the epoxy has been baked off the windings I'm not thinking about AC ripple being the culprit. It's usually the driver/owner that is the source of the wear and tear and breakdowns.


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## Slott V (Feb 3, 2005)

A filtered power supply or an adequate inline capacitor will allow your little armatures to run cooler by reducing the dirty AC half wave ripple output commonly found in mass produced, resin filled electronic transformers.

Steve Medanic has some good articles on his website regarding adding capacitors to existing power supplies and also a good page on batteries vs. regulated power supplies for HO slot car tracks. His experience and information should lend further knowledge to the topic.

Batteries and regulated power supplies:
http://home.comcast.net/~medanic/Tech-PS.htm

Connecting Multiple Power Supplies and/or Capacitors to a Track
http://home.comcast.net/~medanic/MPS/MPS-1.htm

Greg Williams of AHORA put out a very interesting article years ago showing on an O-scope the actual AC ripple left from a stock 'DC' wall pack:
http://www.planetofspeed.net/phpBB3/viewtopic.php?f=6&t=3757


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## alpink (Aug 22, 2010)

I wanna look happy. OK?


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## rbrunne1 (Sep 22, 2007)

This thread is looking like "another day at the office" 

I'm glad to see that electrical engineers have differences of opinions just like us bridge engineers-good thing bridges don't have many moving parts :freak:


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## Dslot (Sep 2, 2007)

*New Data*



alpink said:


> I wanna look happy. OK?


 You may get the chance, Al. 

Earlier today, I went back to the work of getting the stubborn Matchbox Motorway layout (described here, for any who haven't seen it) to maintain a slow, steady speed for display running. At minimum speed, it slows down and speeds up as the various points of friction and loading change along the 14 feet of drive spring channel. Eventually it stops altogether, as the motor stalls against forces that have rearranged themselves to become too much for it.

Inspired by this thread, I thought about eliminating electrical resistance from AC ripple to give the marginal motors as much chance as possible to do their job at low speed. 

I checked the CAPACITORS drawer and found a 470-µF cap left over from the previous slot setups, so (making _*very*_ sure which powerpack terminals were positive) I touched the capacitor leads to the terminals while one lane was running at slow speed (4.5V). The lane speed increased immediately. I repeated several times with the same results - w/cap=faster; w/o cap=slower. After a while the lane bogged down with the motor stalled; I touched the capacitor to the terminals, and it started up. 

I tied the capacitor permanently into the circuit for the more balky lane. After running both lanes for a few minutes, the motor on filtered DC was significantly cooler than the other lane's motor. I immediately called Carol to ask her to stop at Radio Shack on her way back from Austin and pick up a couple more capacitors ("a couple of _WHAT_?" "Umm ... just call me when you get to the store and I'll talk you over to them").

So I'm now convinced that a filtering capacitor can provide a practical improvement in at least some small DC motors' performance. These motors appear to be the common tin-bodied low-voltage round-can style. Contrary to what I said at the beginning of the Motorway thread, they operate at 9V max from little Matchbox powerpack. To get a bit more reserve amperage, I am using cheap HO trainset powerpacks, one per lane. They deliver 4.5 to 12V, depending on the speed-control setting (17V without load).

That's all for right now. My capacitors ought to be coming through the door any minute. And Carol too, of course. :wave:

-- D


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## SwamperGene (Dec 1, 2003)

OK D, but the first problem I see is that you used Matchbox and the word practical in the same context.


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## Hornet (Dec 1, 2005)

Tried a 16v 2200uf cap on my old homemade bench dyno,which is nothing more then a stripped down 6/12 volt battery charger.
With cap the charger's loaded output voltage jumped from roughly 11.3 to 14.9 volts ,the wheel driven slave motor's output jumped from 2.3 to 3 volts.
The temp with-out cap roughly 168F on my gun,with cap in place temp went up to roughly 172F,but that's probably due to the higher RPM and output voltage the car was generating with the cap in place.
Just what i found playing around with a known dirty power supply,a battery charger:wave:


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## bondoman2k (Jan 13, 2003)

Ya know, you guys are making it sound like I gotta be an electrical engineer to hook up my track! :freak: Geez Louise, I have a HO scale 1/8 mile! The timed part is like 7 feet! Plus, I ain't gonna be running on this thing but maybe an hour or two every two or three weeks! 
All you guys are starting to make this sound like something I gotta go back to college just to hook up a power supply.  I wanna RACE! I DON'T wanna spend 3 or 4 months to hook this up, then go back to school and get some kinda degree just to have FUN!
LOTS of 'explanations' and 'theory' here, but NO ONE has put in ANY kind of simple, 'step-by-step' on how to actually hook all this stuff up, unless I missed something in one of those links. How 'bout a "Layman's" explanation? I know absolutely NOTHING about all this Cap stuff. There's GOTTA be a simple sketch somewhere, AND some pics or explanation of what KIND of Cap I would need. 
Put it this way, as it stands right now, it just is NOT worth it for me to go to all this extra work, just for my purposes. IF, later on, I see that it may benefit me to do all this on a 'Better' track, I will figure it out. But for now, just gonna hook up the charger thingy I got, solder in one or two taps straight into the wiring, hook up my timing system, and RACE! 
Ron (Bondo) :dude:


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## AfxToo (Aug 29, 2003)

Ron, I totally hear you and I also struggle with how deep we should take some of these discussions because of the exact issues you bring up. Like most any hobby slot cars have a huge range of technical details that one can choose to consider when probing into the infinite minutia. At the same time you have to look at the other end of the spectrum, toy race sets come with ready to run cars, power packs to make those cars move, and controllers to control how fast they move. You know what? Those sets work right out of the box and without having to break out your TI-89 (for you newbies), HP-41CX (for you graybeards), or slide rules (for you Vibrator fans). Plug and play all the way. 

So it's all about picking where you want to play in the hobby and feeling assured that you are going to get more out of it than what you are putting into it. I contend that you can do exactly that and rest assured that all is well with the world and the way you decide to engage in your hobby. If it makes your brain hurt to try and think about it - don't. Everything will be fine.

In defense of some of the technobabble, many of us were inspired by slot cars and other hobbies (like RC) to pursue careers that involve the same or similar technology. So the technical stuff is ingrained in us and has somewhat of a bond with our larger life, beyond 1:64 scale. It's up to us to decide how to manage that, because if you go too far it can be a distraction, or should I say the hobby ceases to be a distraction from everyday life that it really needs to be. 

Finally, we are not alone in "tech'ing up" a hobby. I know several people who are involved in hobbies/crafts like scrap booking and card making and I can attest to the fact that those hobbies are pretty open to getting out of control with very expensive and specialized equipment and tools. You don't want to know how much cash outlay things like Cricut machines can involve, unless of course you can use this as a way to parlay a bigger allocation for the "his" part of a his-and-her hobby fund. Not that I would ever play that card......


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## 440s-4ever (Feb 23, 2010)

AfxToo said:


> In defense of some of the technobabble, many of us were inspired by slot cars and other hobbies (like RC) to pursue careers that involve the same or similar technology. So the technical stuff is ingrained in us and has somewhat of a bond with our larger life, beyond 1:64 scale. It's up to us to decide how to manage that



That's well said. Even if this thread maddens others it delights me! 

I would also like to say, with a huge amount of joking sarcasm, that playing with electric motors on wheels is probably not the best hobby for an electro-phobe :tongue:


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## Dslot (Sep 2, 2007)

*Note important REVISIONS in this post - Dec 27, 2010*

Ron sez:


bondoman2k said:


> There's GOTTA be a simple sketch somewhere,


There is now.










Sorry, Ron. I didn't intend for this thread to intimidate anyone, and I'm sure the rest of the guys didn't either. Millions of kids and adult hobbyists have had all the racing fun they wanted with _*no capacitors*_ at all. It's just an interesting fine point of the hobby that some like to discuss.

I did up the diagram because you asked, BUT since I *don't know poodle-dumplings about drag racing* (and little enough about capacitors), you might want to wait for some of the technical heavy hitters to bless it before you reach for the soldering iron. Can I get an "Amen" from our tech wizards? I'll edit the drawing if I need to.

It just shows two versions of the basic power-wiring for one lane of a dragstrip. The first version is how I'd have done it before this discussion. The second reflects Alpink's comments earlier in this thread (#20).

No braking, timing, starting or Xmas Tree circuitry is shown. You're on yer own for that specialized drag-stuff.



> AND some pics or explanation of what KIND of Cap I would need.


It ought to be clear by now that we're still figuring *that* out. 

If it was me, and I was doing the Alpink's Cap-at-Every-Tap system, I'd sure be inclined to use the 470 µF 35V ones, because they cost $1.37, and the 4700µF ones are over 5 bucks each (Radio Shack prices - probably a lot cheaper at Mouser or Digi-Key on the web). 

My diagram shows an axial-type electrolytic capacitor hooked up properly (I think). The arrows printed on the case point to the *NEGATIVE* terminal. Make sure that they go to the NEGATIVE lead. If a 470µF explodes like an M-80 when hooked up backwards (well, that's the way I remember it anyway), one of those 4700 jobs must be the equivalent of a tactical nuke. Watch yer fingers. *NOTE: This paragraph was INCORRECT in the original version, as was the diagram. Polarity was reversed, leading to a possibly dangerous situation. If you downloaded previous text or diagram, please DISCARD the file and replace it with the current corrected one. See post 62 later in this thread for full information.*



> ... as it stands right now, it just is NOT worth it for me to go to all this extra work ... IF, later on, I see that it may benefit me to do all this on a 'Better' track, I will figure it out. But for now, just gonna hook up the charger thingy I got, solder in one or two taps straight into the wiring, hook up my timing system, and RACE!


That's a good approach, too.

Merry Christmas and many Happy Burnouts. :wave:

-- D


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## alpink (Aug 22, 2010)

what D-slot said!


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## SwamperGene (Dec 1, 2003)

I'd think that adding caps would also affect driveability...would they not be technically adding "coast" to a car?


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## alpink (Aug 22, 2010)

Gene, sure they would. I know folks who put them in the t-jets to supposedly cut down on the RF, but, yeah, the stored energy could be dissipated after track power is cut and add a section or more. of course if they are not permitted in class and the cars are properly teched, it is not an issue. but, it would seem that said racers (pros & semi-pros) rarely post here although I bet they lurk. most of the folks who post here seem to be home track racers een if they have been able to afford expensive tracks.


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## Hornet (Dec 1, 2005)

Gene,my little switching Meanwell power supply,will drive a drop-in Neo car for almost a half a lap when i turn just the power supply off,and leave the relays energized,good sized cap in it.I would agree with your assumption they add coast if they're after the controller:thumbsup:


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## AfxToo (Aug 29, 2003)

A cap acts just like a battery so putting at large enough one in car or controller would give you a little extra power after the main power source is removed. Generally speaking a tiny filter cap would not make much of a difference. Recall that I said that large value caps tend to be very large in size but the exception to the rule is something called a "super capacitor" or "ultra capacitor" which can pack a lot of capacitance in a small package.


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## Slott V (Feb 3, 2005)

bondoman2k said:


> Ya know, you guys are making it sound like I gotta be an electrical engineer to hook up my track! :freak: Geez Louise, I have a HO scale 1/8 mile! The timed part is like 7 feet! Plus, I ain't gonna be running on this thing but maybe an hour or two every two or three weeks!
> All you guys are starting to make this sound like something I gotta go back to college just to hook up a power supply.  I wanna RACE! I DON'T wanna spend 3 or 4 months to hook this up, then go back to school and get some kinda degree just to have FUN!
> LOTS of 'explanations' and 'theory' here, but NO ONE has put in ANY kind of simple, 'step-by-step' on how to actually hook all this stuff up, unless I missed something in one of those links. How 'bout a "Layman's" explanation? I know absolutely NOTHING about all this Cap stuff. There's GOTTA be a simple sketch somewhere, AND some pics or explanation of what KIND of Cap I would need.
> Put it this way, as it stands right now, it just is NOT worth it for me to go to all this extra work, just for my purposes. IF, later on, I see that it may benefit me to do all this on a 'Better' track, I will figure it out. But for now, just gonna hook up the charger thingy I got, solder in one or two taps straight into the wiring, hook up my timing system, and RACE!
> Ron (Bondo) :dude:


As with any hobby you can take it to the "9th" degree so work at your own pace and fuel your passion with whatever the limits are of your own understanding. Just because your neighbor runs a McIntosh sound system doesn't mean your Sony is less than adequate.

DSlot is the master here at offering drawings for the 'average guy' like most of us. Excellent illustrations. I admire your skills D!

Scott


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## Slott V (Feb 3, 2005)

SwamperGene said:


> I'd think that adding caps would also affect driveability...would they not be technically adding "coast" to a car?


In theory yes but if your wiring is done correctly it shouldn't as the relay is the shut off for current to the track when the computer ends a heat/race. Also, the cap is inline for total track power, so if any residual power did dump from the cap it would be on all lanes, no?


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## alpink (Aug 22, 2010)

I think the term is "Nth" degree?


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## usdra (Jan 23, 2007)

Trackmate has a 0-30 volt 0-10 amp power supply for $145. For the price of those small chargers you would be further ahead buying one of the Trackmates. I have one of his 0-20 amp units & it works great. http://www.trackmateracing.com/shopdisplayproducts.asp?id=17&cat=<b>Power+Supplies</b>

Eric (mobydidit)


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## SwamperGene (Dec 1, 2003)

Slott V said:


> In theory yes but if your wiring is done correctly it shouldn't as the relay is the shut off for current to the track when the computer ends a heat/race. Also, the cap is inline for total track power, so if any residual power did dump from the cap it would be on all lanes, no?


 
Yes I should've clarified....any cap installed _after_ any relay.

Yes a single cap in the main power line would dump anything it was holding to all lanes, however I don't think it would do so evenly.


*Also worth noting is that some wall-warts _do_ have a cap in them.


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## Grandcheapskate (Jan 5, 2006)

Rolls said:


> No modern computer relies on it's external brick for the quality of power of its circuitry. For that the computer internally filters and regulates the power to clean it up. If you try to run your computer on it's brick and bypass all the internal clean-up circuitry that would be a very bad idea.


 I was in a computer mega-store the other day and a 400w power supply was only $25 ($35 for a another, although the specs looked the same). The specs said it had a 3.3v, 12v, -12v and 5v DC output. The 12v line indicated it put out 20 amps; I don't remember the others although they were all over 10 amps. The 5v line had some other letters after it, but I can't remember what they were.

With that type of power output and at that cost, why would you fool around with more expensive laptop chargers? You could combine the output lines and get 12v, 15.3v, 17v or 20.3v, although you'd get less than 20 amps (I'm guessing).

But my question, based on Rolls' statement, is whether or not a computer supply puts out clean power. Is there circuitry on the motherboard that cleans it up? Certainly a computer requires much cleaner power than our toy cars.

And what is a -12v line?

Thanks...Joe


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## Rolls (Jan 1, 2010)

Joe, 

While laptop chargers and PC power supplies don't put out power quite as clean as a good lab supply, I gotta echo what AfxToo pointed out - our cars don't really need perfectly clean power. 

My bigger concern with a PC power supply would be whether you really can stack it's outputs to get something above 12V. Offhand, I would guess all their voltages would be referenced to their chassis ground rather than floating, so you couldn't stack them. Mind you, I'm just assuming and haven't tested them. My guess could be wrong. Maybe someone who knows more about those specific types of supplies can chime in.

Merry Christmas,

Rolls


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## Dslot (Sep 2, 2007)

*CAUTION - Previous Drawing and Post is INCORRECT*

*CAUTION* - My original text and drawing in Post 49 of this thread was *incorrect* and could lead to a potentially *DANGEROUS* situation.

I have replaced the errors with corrected versions.

Working from memory, I INCORRECTLY indicated that the printed stripe on the case of an electrolytic capacitor pointed to the POSITIVE lead. It actually points to the *NEGATIVE* lead (at least in the samples I have on hand) and is sometimes printed with a negative sign. Always check the sign on the stripe.

This error could result in someone hooking an electrolytic capacitor in reverse, and causing damage to the capacitor and possibly an eventual firecracker-type explosion of the capacitor, capable of causing injury. 

If you *downloaded the diagram* or text, please REPLACE your file with the updated version and DISCARD ALL COPIES of the earlier version. 

If you *hooked up a circuit* with the capacitor installed as indicated in the original version, IMMEDIATELY shut off power to the circuit and REMOVE the capacitor from the circuit - DO NOT HOLD the capacitor with your fingers - use pliers. Do NOT touch the leads or connection points - a capacitor can store a painful high voltage charge. Wear safety glasses for this operation.

To discharge the stored voltage, hold the capacitor with pliers, and touch both leads at once to the metal shaft of a plastic-handled screwdriver. You may get a large spark. Safely discard the damaged capacitor and replace with a new one in the proper polarity.

I apologize for this error, and hope it didn't cost anyone inconvenience (or worse). Next time I'm tempted to write from memory in possibly dangerous situations, I'll be sure to recheck the facts first. 

I am very, very sorry.

-- D


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## NTxSlotCars (May 27, 2008)

Why not just use batteries?


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## Hornet (Dec 1, 2005)

A battery's just as dangerous,if not more dangerous,especially in a basement.
Hydrogen makes a hell'va bang when it's ignited,one of the of the downfalls of a battery while it's being charged:wave:


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## NTxSlotCars (May 27, 2008)

Well, you would either have to have a really small basement, not big enough for a slot car track, 
or some really bad batteries to build up enough concentration of hydrogen to have an explosion.
The kind of batteries I use, one charge will last you all winter. As far as the danger, 
any power supply is dangerous if it's not fused, or have some sort of breaker.

I guess the real difference is if you want adjustable power.
I used 6v batteries, so I have a switch for 12v, 18v, and 24v, but it never leaves 18v.
For me, battery power is just so smooth and clean, I can't see switching back to a power supply.
It's a noticeable difference.:wave:


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## Bill Hall (Jan 6, 2007)

Certainly they are Rich.

For people like you and I, and a handful of others on our board; who are trained for their safe usage. Hornet simply points out the obvious that; hydrogen generators with built in lighters on top arent exactly an end user product for slot-tards.


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## Hornet (Dec 1, 2005)

Rich,i swore by batteries for years,till i had a lucky experience blowing one up.
We we're starting a grain auger at about -20F,had the booster cables tied to the battery,and we we're using a tiger torch to warm the crankcase,the battery was over 5 ft away from the tiger torch when it blew-up,the battery was sitting in a 2inch angle iron base,and it was like somebody had taken a saw to it,and cut the part off that stuck above the angle iron,both of us standing there,never had a mark on us,but the garbage bins a 100 ft away,had chunks of battery blew through them,after that,i gained a hell'va lot more respect for the explosive power in a charging battery,did i mention this was outside,not inside:thumbsup:
If you're running batteries,put something between them and a concrete floor,a bare concrete floor will drain the charge from a battery.
Those must be some mighty good batteries you got there,to go all winter on a signal charge,even a sitting battery looses it's charge over time.
LOL,i'm the opposite,i ran batteries for years,then went to a power supply,i'd never go back to batteries,and the track manager just happened to be around when we blew up the grain auger's battery,so she's not to inclined to have potential bombs in her basement
Rick


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## NTxSlotCars (May 27, 2008)

I guess its just what you are used to. Kinda sounds like your battery wasn't hooked up right.

This is what I use... 6v deep cycle pallet jack/golf cart batteries.










The charger and batteries are housed in a neat case.










It's one of them new style automatic chargers with the equalizers and all.
These batteries are in series, and I have a leg hooked up to 2, 3 and 4 for the track
It always stays on the third one, because most cars just run best on 18v.
If your batteries are clean, and not overfilled, they shouldn't drop much charge over a few months.
It was my 16 ft oval I used to have that sold me on battery power.
The difference was night and day over a couple of different power supplies I tried.
I never bought a high end power supply. More affordable solutions have shown up on here since.


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## Hornet (Dec 1, 2005)

Nope cables were right.
A battery has a serious outgassing problem when it's being charged.
You're set-up is very tidy and looks properly done,but i'd still keep it away from the water heaters pilot light:thumbsup:


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## cwbam (Feb 8, 2010)

Wow that's some AMPS!!!
I think what we are really talking about is various voltage 12 volt for GJets to 24v for some
pancakes. The more amps the better. (check your relay I think mine is 40 amp)
Ohm's law is the reason. A 4 lane track with 3.5 ohm Arm's in HPx2 likes amps and doesn't more amps help conduction and less shoe wear? Check out an old Nintendo Game cube
12volts 3 amps.


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## Joe65SkylarkGS (Feb 15, 2010)

I have a question after all this, Is the new AW Drag race John Force set, set up with a capacitor system?? This is a Drag Strip Specific set. Not like the NTB set which is an oval.


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## usdra (Jan 23, 2007)

I used to run batteries also on my drag strip. Switched to power supplies 1 for each lane adjustable from 20-28 volts @20amps. My cars lost nothing et & mph was the same. Except for the .2 ohm neo Top Fuel dragsters. Added a couple caps & the dragsters came around. I have less money in this system than in batteries & no maintenence. Want to race, flip switch on. Done racing, flip switch off. It also takes up alot less space. My 4 lane (soon to be replaced with a Max Trax) is powered from a fully adjustable 0-30 volt 0-20amp Trake Mate supply & will be getting caps added soon. The best part of these systems is no voltage drop during a race day no matter how hard you run them & if you want to run a different voltage for different classes just turn a dial. Here is a link to how to wire up 1 or more power supplies & capacitors. http://home.comcast.net/~medanic/MPS/MPS-1.htm

Eric
www.mobydiditperformance.com


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