Battery question

[Daniel C]

Hey everybody. I'm looking to get a new battery 7.4 2s lipo but there's also a c count number. I'm guessing that is a cell count but I'm not shure what would best a low count or a high count. I don't know if it matters but I'm installing it into a crawler with a 540 80t motor.

 

[Xraycer]

For a crawler, C rating really isn't important. A C rating of 25 would be fine. This also depends on your crawling driving style. If you're someone that likes to regularly punch it hard to pop over obstacles, then a higher C would be beneficial.
So, if you're looking for speed and power performance, such as for racing and bashing, then you would want at least 50.

 

[WVNed]

2s 3s 4s are the cell counts 2s would be 2 cells in series
C rating is how many amps the battery can dump to supply a load. so a 50c battery and a 25 c battery may be the same size in Mah but the higher C rating battery can supply a higher maximum current draw from the motor.
Batteries climb in cost as the C rating increases.

 

[WickedFog]

C rating basically represents the quality of the battery. The higher the C, the better the battery (as long as the manufacturer is honest )

To know what a battery is supposed to handle take the mAh divided by 1000 x the C rating. So a 5000mAh battery at 50C looks like this:

5000mAh ÷ 1000 = 5Ah
5Ah x 50C = 250A discharge.

Higher C rated batteries take less stress at higher loads. Say you had a 35C battery. If your electronics, cables, and connector were able to draw a 35C load throughout the charge of the pack, the pack would likely be toast. If you did the same with a 100C battery, it would be much less stress on the battery. That being said, the higher the C rating, the longer lifespan a battery will have if used under identical conditions. And by lifespan, I mean the overall life of the battery. Not the run time on a charge.

Your C rating will also degrade over time. LiPo batteries don't last forever. So it is good to have a charger that displays the resistance of your battery's cells, to keep an eye on things. Just because a battery said 50C when it was new, doesn't mean it is still 50C.

If you want to learn more, there is a really good writeup here with info on checking the actual C rating of your batteries...
https://www.rctech.net/forum/radio-electronics/1009300-warning-lipo-c-discharge-ratings-invalid.html

 

[Daniel C]

Ok cool thanks. I am the kind that likes pure power. Sometimes alittle speed but I have other rigs for that. I actually have to put the battery on hold because the rc is lagging. The truck will run just extremely slow. I tryed other motors but it's all the same. I think it's the ESC because the receiver looks to be working fine. Atleast the lights and stearing is. Oh well mabey super rooster ain't so super anymore. Well I was wondering how long it would hang in there. Lately it's been one thing after another. Well thank you for answering the question.

 

[WickedFog]

Ok cool thanks. I am the kind that likes pure power. Sometimes alittle speed but I have other rigs for that. I actually have to put the battery on hold because the rc is lagging. The truck will run just extremely slow. I tryed other motors but it's all the same. I think it's the ESC because the receiver looks to be working fine. Atleast the lights and stearing is. Oh well mabey super rooster ain't so super anymore. Well I was wondering how long it would hang in there. Lately it's been one thing after another. Well thank you for answering the question.

If you want a bit more speed, you can always put a bigger pinion gear in it.

 

[Daniel C]

If you want a bit more speed, you can always put a bigger pinion gear in it.

Speed is not what I'm looking for in my crawler. I just wasn't shure if the extra cells would last longer or give more amps or what kinda. I don't know just wondering since a 2s lipo and a 4s lipo is a big difference if the cells would be something like that.

 

[WickedFog]

Going to more cells increases the voltage, which will increase speed. You don't want to run more cells than your electronics can handle.

What crawler are you talking about here?

 

[Xraycer]

Speed is not what I'm looking for in my crawler. I just wasn't shure if the extra cells would last longer or give more amps or what kinda. I don't know just wondering since a 2s lipo and a 4s lipo is a big difference if the cells would be something like that.

How long a battery last is indicated by mAh. mAh also determines the actual overall physical size of a battery pack.

 

[Daniel C]

Going to more cells increases the voltage, which will increase speed. You don't want to run more cells than your electronics can handle.

What crawler are you talking about here?

One I kinda made. It was a wl toys trophy truck now completely modifyed. Basically only the chassis is what's left of that now.

 

[WickedFog]

One I kinda made. It was a wl toys trophy truck now completely modifyed. Basically only the chassis is what's left of that now. View attachment 129526

Oh, that is awesome!

 

[Daniel C]

Thanks I'm working with what I have around the house and I really like this she'll. Hey thank you again so much for all your help with my many questions. You have been a big help