Qs about batteries in a e-Revo

[loa]

Hello,

Trying to get my hands on a revo roller so that I can start my conversion.

I'm also looking at Lipos, and I'm getting confused with the Cs and mAh combination.

First question: am I getting this right?:

A 4s 8000 Lipo rated at 10C should be roughly equivalent to a 4s 4000 Lipo rated at 20C.

They should have roughly the same amount of power, but would the runtimes be different?

Second question: would a 4s 8000 TrueRC Lipo (rated at 10C) be decent in a e-Revo? (planning to use a 9XL).

Third question: would I get the same power using two 2s 8000 Lipos instead of one 4s 8000 Lipo?

(Reason I ask is that I could use those 2s Lipos in my Rustler, whereas I couldn't do that with the 4s pack.)

Thanks a lot,

Loa

[Sammus]

A pretty crude outline:

The mah (milliamp hours) rating is a measurement of the capacity of the battery - all other things equal this will pretty much determine your runtime eg a 8000mah battery can deliver 8000mA (=8A) for one hour. Roughly the C rating tells you how much current the battery is capable of delivering. So if its 10C battery, that means it can deliver 10x its rated capacity (the milliamp hours, except without the hours), so it can deliver 10 x 8000mA = 80A (in a burst or continuous or whatever the C rating is for.)

I this 4s 8000 is pretty popular in a revo, so you should be right.

And yes, two 2s batteries connected together in series is the same as a single 4s pack. This is exactly what I do, I have two 3s packs that I use in my rustler and my crt.5, then join them for 6s in my revo.

[loa]

Thanks Sammus!

So the 4s 4000 20C would have as much power but would have roughly half the runtime as the 4s 8000 10C.

Ok. Another related question: what range of speeds should I expect with a 80amps battery in a e-revo using MM and 9XL?

Nothing specific as I know it relate to the gearing, but I'd like to have a revo that reaches somewhere around 35mph.

Does anyone know if the 4s 8000 10C can achieve that?

Thanks,

Loa

Hello Loa! Take a look at this thread, that's what i've tell you yesterday on the quebecrc.org forum about my revo direct drive.
http://www.rc-monster.com/forum/showthread.php?t=10651

David

[loa]

Thanks David, I'll look it up.

Loa

[Sammus]

Originally Posted by loa

Thanks Sammus!

So the 4s 4000 20C would have as much power but would have roughly half the runtime as the 4s 8000 10C.

Ok. Another related question: what range of speeds should I expect with a 80amps battery in a e-revo using MM and 9XL?

Nothing specific as I know it relate to the gearing, but I'd like to have a revo that reaches somewhere around 35mph.

Does anyone know if the 4s 8000 10C can achieve that?

Thanks,

Loa

I think 80A wouldn't be enough to get it moving initially. Maybe if you were using the tekno clutch it would, but a big truck requires a bit of energy to get moving, and I suspect that spikes would be well over 100A if you floor it from a stand still. for 8000mah batts I would want at least 15C, preferably 20C. I think youll be able to get 35 out of it with that setup OK. I'm pretty sure I've seen some builds with nearly that exact combo, may want to have a look for them or something because this is all speculation for me now :)

[loa]

Thanks for your input Sammus. I think I'm gonna start another thread with that question. I'll check trueRC's site to make sure of their C ratings.

Loa

Flightpower 25C
That's the best.......

Originally Posted by Sammus

I think 80A wouldn't be enough to get it moving initially. Maybe if you were using the tekno clutch it would, but a big truck requires a bit of energy to get moving, and I suspect that spikes would be well over 100A if you floor it from a stand still. for 8000mah batts I would want at least 15C, preferably 20C. I think youll be able to get 35 out of it with that setup OK. I'm pretty sure I've seen some builds with nearly that exact combo, may want to have a look for them or something because this is all speculation for me now :)

Myself and several others are having good experience with the 8000mAh TrueRC packs. Although they are only rated at 10s, it seems they can do much better. They are a whole world better than the 20/30c maxamps 5000's I was running, all else the same. Somewhere around half the cost too :).


J.

[loa]

Thanks for the info 83gt!

You're probably going to save me a lot of cash! :-D

Loa