I am currently using a brushed motor. No marks serial codes or anything. The battery it came with is a 40c 2200mAh LiPo. I have a Traxxas 25c 7600 mAh LiPo that i would like to use on it, but i'm not certain i can. Is this something i can do?

i wouldn't use a 25c lipo for anything.

You didn't mention what vehicle you're running. When Lipos first became affordable, most of them where 20-30c and they were definitely a step up from NiMH. And given the theoretical amp output of c is c x capacity, your 25c battery can put out more current than the 40c one.

Just be aware that brushed motors are less efficient than brushless and therefore will overheat quicker. It's quite common for people to have batteries that can run longer than the brushed motor can.

Normally those 2200mAh packs are designed for 1/18 cars, I have actually tested them in a 1/10 car hooked up in series to act as 4S for grins so it's possible to run them in 1/10 but don't expect very long run times:


the 7600mAh pack is definitely more suitable for 1/10 cars and what I would prefer, some of my very first LiPo packs were 20C and they performed perfectly fine for brushed and brushless applications for 1/10 cars back in the day:

A few thoughts -

A RTR with a unmarked brushed motor is probably a 550/540 silver can, or a smaller 380. These "silver can" motors don't generally draw much in the way of amps, so lower C rated packs can work for them fine.

Until the last few years, the vast majority of Lipos- regardless of how they were labeled or sold - were around 25C or less. A true 25c 5000mah pack is a pretty decent battery, good for most car applications until you get into some bigger amp hungry motors. Traxxas Id packs are not great for what they cost, but from what I can tell, (not a lot of info) they come pretty close to being a true 25c pack, so I doubt there are many brushed motors sold in RTR RC's that will stress one.

The Traxxas battery will probably work just fine and according to the c-rating, it is capable of much higher current than the 2200 that came with your car.

2.2A*40 = 88A

7.6*25 = 190A

All those c-ratings that you see above 50C are pretty much BS anyway. Even if the cells can handle that current, the wire and connecters used can't (50C, 5000 would be 250A, 12AWG would be really toasty really fast).

This is a great illustration where I like to call this reference "Rated Amps" or "Relative Amps" = rA

so the math in my head looks more like
2200mAh = 2.2Ah
7600mAh = 7.6Ah

2.2Ah * 40C = 88 rA
7.6Ah * 25C = 190 rA

Many years ago I used to study discharge graphs on my packs to help me understand the correlation between a packs C rating and performance, I also used this information to determine the validity of a brand of batteries claim for a given C rating and had found that the higher the rA the better the pack performed in general (when new):




What I found was that as packs aged it became impractical to determine the true rA and have since adopted the concept using IR instead, more info here on my thoughts around IR:
https://www.rcgroups.com/forums/show...0#post43510433

Yes, the IR, average voltage and runtime are the best way to evaluate packs of all ages. The "C" rating system has been BS for at least 10 years now. SMC also has their own system that has some merit to it.