# lipo question



## NoMercyRC (Nov 2, 2010)

i was just wanting to know how much more power does a lipo battery put out compared to a standard 7.2v nimh battery. Cause im wanting to put a lipo in my rc18mt an i was wanting to know if i will get more speed an power from a lipo.


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## guver (Jul 31, 2002)

As a "type" of battery it puts out no more or less "power" than any other type of power supply that is supplying DC voltage. Power is a function of the voltage and the current of your power system and a battery simply has to maintain a voltage of your choice at a current of your choice.


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## 4ThePinkRacing (Apr 30, 2010)

lipos hold voltage steady longer like power curve i guess .. iam sure iam sayin it wrong so someone correct me ... but it stays smoother longer not a hard drop off X amount of mins into the pack ..

and last in life much longer like year to 2 to 3 years depending on useage as to the sub c cells or so .. they dont last as long in life


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## NoMercyRC (Nov 2, 2010)

ok thanks for the help an the answers.


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## markd5469 (Aug 24, 2008)

A "standard" (not some super-low IR, matched, zapped high-bucks set) 6-cell nihm is a nominal 7.2v. A standard 2S lipo is 7.4v. That means a lipo will have a slight voltage advantage over the first few minutes of the race. Since in DC applications higher voltage = higher power, that is an advantage. But not enough to make that the reason to buy one. 

Over the length of the race, the lipo holds its voltage near its maximum for a complete 4-5 minute race (if it is properly sized - see below). The nimh pack will be great on the first lap or two, and then start to taper off. By half way through the race, it's giving you less voltage on every lap. Therefore your fastest lap with a nimh will usually be in the first 1/3 of the race. With the lipo, it may be your last lap. I'd consider that an advantage.

Charge cycles - the info above is correct. You can get more charge cycles out of a lipo than a nimh (everything being done right). You also don't have to "rest" them between races. You can come off the track, and let them cool for a few minutes, and charge them back up and race them again. You can't do that with nimh packs. For racing you need at least 2 nimh packs for each class you race, but you'll only need one lipo. Another advantage.

Lipos cost more. But now days, not twice what nimh packs cost.

Lipos MUST have a lipo specific charger. NEVER charge a lipo with a nimh charger.

Lipos can not be run until they die completely, and should never be "fully discharged". Draining them below 3.0v per cell (some manufacture's say 2.8) will damage the chemistry, and they are often junk after that. So use an ESC with lipo-voltage cut-off circuitry, and make sure you set it the the cells in your lipo pack to protect it.

The lipo's mha rating is important, to make sure it matches your motor and usage. Too low, and it will drain the pack too far too quick, which can damage or destroy your new pack. Its better to have more mha than you need than less, within reason.

Lipos (most reasonably priced ones) cannot be charged at high amperage rates. Doing so can be dangerous. Don't be in a hurry to get it charged, and turn up the amps on your charger. That can ruin the pack, and damage your charging area.

Lipos should be monitored when they are being charged, and should be in a lipo-safe sack. While they are much safer than they were when they first came out, go on utube and search for lipo sack, and watch the videos of lipo fires. That's real, and I've had two soft-side packs get damaged racing and catch fire when I charged them the next week. Thank goodness for the lipo bag.

Overall, handled with proper care, maintained properly, they are an advantage. But like anything else that promises more power and more run-time, and shorter down-time between charges, there are trade-offs that should be considered before you make the move.


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## NoMercyRC (Nov 2, 2010)

thank u very much u were very help full.


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