# Norwegian halt use of 4200 NiMh!



## gezer2u (Sep 25, 2001)

Official press release:
http://www.redrc.net/wp-content/uploads/2007/11/press-release-norwegian-motorsport-federation.pdf

Discussion on the ruling:
http://www.oople.com/forums/showthread.php?t=6186


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## wacko (Sep 18, 2003)

It amazes me that someone has not gotten injured due to the exploding batteries. I personally have witnessed more than 5 battery incidents with the IB4200 cells. I guess once someone loses a digit(finger) then we will pay attention.


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## NCFRC (Aug 4, 2005)

Please Clarify That These Are The Intellect Cells Only !!!!


Please Don't Put All 4200 Cells In This Neg. Category.


The Ep-4200 Is Still One Of The Best On The Market !!


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## wacko (Sep 18, 2003)

NCFRC said:


> Please Clarify That These Are The Intellect Cells Only !!!!
> 
> 
> Please Don't Put All 4200 Cells In This Neg. Category.
> ...


true... The only ones to explode (that I have witnessed) are the Intellect


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## Kenwood (Oct 18, 2004)

wacko said:


> true... The only ones to explode (that I have witnessed) are the Intellect


Not Quite.. Saw 2 EP4200's Go KAPUT this weekend.. I will say the EP4200 does not have the explosive force that the IB4200 has... The BANG was not as loud.. But it was a BANG..


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## wait a minute (Oct 11, 2001)

i had a pack vent under my charger. it was charged while in delay to repeak and a guy i race with said it was spewing allover the place. i grabed it with a pair of pliers and took it outside in the cold and within a minute it exploded sounding like a shotgun going off and luckily it didnt blow a hole in the side of the building.


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## tweakedt3 (Aug 12, 2004)

I must say, since the nihm came on the scene a few years back. I remember alot of 3000 and 3300 just exploding. It happened at least once every couple of weeks. I would blame alot of it on battery maintanence and bad charging practices. I see alot of guys re-peaking batteries way more than they need to be.


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## hopper (Oct 12, 2006)

I had a pack explode while discharging. I had a temp sensor on the pack, so it blew up at under 130 degrees. It burned out the inside of my trailer and I lost most of my stuff!


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## DJ1978 (Sep 26, 2001)

*Knee Jerk reaction*

I have been racing for over 10 years and operation a track for over 5 years. I have seen onebattery blow in all that time.
None at my track which has averaged over 150 entries per race for the last 5 years.
I personally have had one blow at my house due to a faulty charger.

No one has mentioned the parameters that have been involved. 
What was the charge rate set at? I know some who will actually try to pour 10 amps in because they are late getting ready or just thing they are giving themselves an edge in the competition.
Same with the Discharge mishaps.... Our dischargers will draw 30 amps... and we say this is what they see in race conditions. BUT on the bench, a fully charged batteryor even partially discharged pack being discharged at 20 or 30 amps constant is not the same as in race conditions where they will see surges to 30 amps or more but not constant and they have air flow over them. A battery even with a partial charger can be dangerous if the discharge is constant 30 amps with no cooling fan sitting on the bench.

So without knowing the specifics, I think this is a knee jerk reaction that has more to do with insurance and worries of people being injured and sueing than actual faulty products. I am all for safety... but to completely hault all electric racing seems extreme.

There is intense competition at National events. Seems like someone was abusing the packs. 
They could even have been prototype cells.
Just my opinion.
Dan


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## hankster (Jan 1, 1998)

There were a couple of threads about it elsewhere on HT. From what I understand the cells weren't being abused during charging and some have even exploded during discharge. Some have gone off only a few 100 seconds into the charge on an "equalized" pack. From talking with a "battery guy" he claims that the insulator inside the cell is breaking down causing it to short internally. It's bad enough that they are no longer being imported into the US.


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## 420 Tech R/C (Sep 15, 2006)

does not surprise me. remember IB said that this batch of 4200 cells would be more stable and would be a better quality cell.I personally beleive that the capacity on sub c size cells was maxxed at the 3800mah cells and that the 4200 cells have actually SURPASSED the capacity that a sub c size casing can handle without becoming fragile , volitile, and unpredictable. there is no need to halt electric racing. as fast as the 4200s go bad it should not be a big deal to pick up some GP 3900 cells or other to keep the race scene going. I mean come on, we used to race stock and mod classes on 1400 scr cells so is it really a big deal to drop back the capacity a little bit. I mean I know that I dont use but 2000 mah running a brushed mod in a 5-minute race , and around 1700 mah running a hot brushless so wheres the real NEED for all the capacity???


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## jflack (Apr 27, 2002)

DJ1978 said:


> I have been racing for over 10 years and operation a track for over 5 years. I have seen onebattery blow in all that time.
> None at my track which has averaged over 150 entries per race for the last 5 years.
> I personally have had one blow at my house due to a faulty charger.
> 
> ...



When you have a cell go off in your hand, you will change your mind! IBs and from what I hear EPs will go boom under norm charging conditions with no abuse required! I know the cell that blew up on me wasn't abused at all, it wasn't even fully charged!


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## gezer2u (Sep 25, 2001)

DJ1978 said:


> So without knowing the specifics, I think this is a knee jerk reaction that has more to do with insurance and worries of people being injured and sueing than actual faulty products. I am all for safety... but to completely hault all electric racing seems extreme.


Dan, there are a lot of post where the specific's were stated about how the cells were treated before they exploded. On the forum that I posted above, there is a post about some one being injured. You can read about IB's exploding on just about every R/C forum. As far as how we charge and discharge being the problem, we haven't really changed the way we charge and discharge. Sure, some may charge at 8 amps and a few may charge at 10 amp's. But there are plenty of reports of problems from those who were using safe settings. The Norwegian Motorsport Federation must have thought it was a major problem. They also decided not to allow either IB's or EP's, so there must be problems with both manufacturers.


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## Kenwood (Oct 18, 2004)

Ive not blown up a single pack yet(FINGERS CROSSED)...BUT in the case of the 3 IB cells and 2 EP cells I saw/felt go up none of them were doing anything out of the ordinary... However I know that I always make it a point to hang around my pit the last 10 minutes of the charge...I hit each cell with a temp gun...mainly out of paranoia and the few times Ive heard a cell vent I immediately shut the charger off. I also charge mine inside of a Tuffak charging stand...So if it blows up it is somewhat contained being a bulletproof matl...


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## Racin'Jason 8 (Nov 19, 2002)

I still say that they are shorting internally and it's not all about charge/discharge temp's...but rather shorting temp's! How else could a guy have a cell pop 2 hours after he used it? huh.


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## brian0525 (Jan 17, 2005)

Not a temp issue I have seen packs that were mis charged and were 258 deg. and not blow up but that was old batches not the new ones.

Something internally has changed, be it in design or bad parts. 

When people say these cells are junk cause they go dead it is a problem, but when they are bad cause they explode that is a whole new level of a problem!


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## 420 Tech R/C (Sep 15, 2006)

Hey guys heres an interesting thought, do you think that maybe the internal shorting is what causes the cells in the 4200's to go dead?? Maybe the ones that are exploding are a few and far between scenario of the actual problem.We have all had 4200's go bad, thats why I went back to racing with my 3300's I kept as practice packs.They might not be as fast on the track, but the cells dont go dead for no reason, and I have never heard of one blowing that wasnt abused. I personally think that the internal short problem has been there with these cells from the get go, thats why so many go bad under proper charging conditions. I think that the exploding here of late has come from the change in the chemistry that was made in the recent batches to try and combat the problem and it has just made them even more volitile.I think that some further r+d requirements coupled with some 'real world' testing standards need to be implemented and adhered to VERY stringently before releasing the next version of these cells. And to be honest with you, I think that there needs to be a recall or trade in credit on the cells out there in use and left for sale on the market. Or is it going to take someone getting killed and the company getting sued and put out of business before something is done about this.Also if you read a couple earlier posts in this thread the EP cells are exploding also , so they are obviously having issues too. So i guess my question to the manufacturers and matchers is what are our options?? They have fought tooth and nail to keep li-pos out of competition level r/c saying that their product is MUCH safer than li-pos, but if they cant get it right I dont really see any other option.


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