I just converted my 8ight t 2.0 to brush less. I was wondering what the difference would be running 2 2s 5000mah batts and one 4s 5000 battery. I know the 4s cost a lot more but why? Why would you run a 4s 5000 when you could just run 2 2s packs and have double the mah.? I'm sure there is a reason but I don't know and am hoping to find out.

Uh, you won't double the capacity using 2 2S packs unless you like the buggy to run at very low speeds.

You double the capacity by hooking them up in parallel but the voltage remains the same as a 2S.

You double the voltage by hooking them up in series but then the capacity is the same as a 2S.

The prices are about the same depending on the "name brand" you elect to use. Compare apples to apples. 2 Pro-Tek 2S is about $180 and 1 4S is about $180 for thesame capacity, less if you want lower capacity. The advantage to 1 4S is a small weight savings and only one pack to handle.

I run 2 5000 2s packs for 4 s total. 10000mah right? So one 4 s would give me less run time correct?

Sure you can do that and it will run forever but very slow, a little faster than walking, since you're only using half of the voltage a 4S would supply.

2 2S packs in parallel = 8.4V @ 10,000mah
2 2S packs in series = 16.8V @ 5,000mah

Which of the above would be faster in your opinion?

running a 8 scale esc and motor setup will hurt the batteries if you are to run them in parallel. Not enough voltage will cause the system to run very slow yes but you really need a minimum of a 3 cell voltage to run a 8 scale esc and motor...

Run time with a 6000mah 4 cell in a 8 scale buggy or truggy will be 20 minutes geared right and be really quick.So I dont really understand why your trying to chase more run time.

Fordy

oops

I run a mamba monster. What I was meaning is if I run 2 2s packs each 5000 mah in series is it still just 5000 mah or would it be 10000? Vs a 4s pack 5000. That's what I mean

Mate in series it is just doubling the voltage and doubling the amp rating but the mah will be 5000mah mate your right...

Hope that helps.
Fordy

Batteries in series doesn't double the amp rating. The amp rating and capacity (5000mAh) remain the same, only voltage increases.

I like to drive hiking trails in my trucks but I have to carry 20 lbs of batteries or carry my rigs home. I've seen 10,000 and 12,800 MaH batteries (Traxxas 7.4v 2s 25c). 1 amp per 1000MaH would be 10 amps, my charger only charges up to 5 amps, would it hurt to charge at that or just take longer? Is there anything else I should know before buying these at $130+??

That will be fine, just take longer to charge.

Thnx..

Forgot to mention many chargers have a timer limit for safety. Might need to turn that up, or restart the charge, to get a full charge when using lower than 1C charge rates.