battery size

[davosfam]

On six cell flat packs, whats the difference between 8.4 and 7.2 volt? Longer run time maybe? Also when changing the connecter ( from tamiya to deans ) you cut one wire at a time, cutting both at the same time can damage the battery correct?

[thomas]

a 6 cell battery is 7.2 volts, an 8.4 volt battery would be 7 cells so it would be a little bigger that the 6 cell .it wont damage the battery cutting both unless the wires touch each other.

[Greatscott]

The two main things you deal with in batteries are Voltage and Amperage...

Voltage is the power, the higher the voltage the faster your motor runs.

Amperage is the capacity, the higher the mha the longer the run-time.

NO... DO NOT CUT BOTH WIRES AT THE SAME TIME!!!!!!!! You'll short the (+) and (-) with the cutter and could shock you, damage the battery, and/or damage the cutter.

The best practice is to cut one wire off, tin, solder and heat-shrink, then do the same thing with the other connector. I know some people do both at once, but if you are new to playing with 'trons, this is the best methode to ensure you don't shock yourself or cause damage.

[davosfam]

Thanks for the info. Was looking at batteries on ebay and thought it ( 8.4 ) was a six cell.

whats the best method for charging a brand new battery pack? Also had a fairly new battery pack go bad, its been fully charged, but when I hooked it up to the truck it still acted like a dead battery. Only had maybe five runs on it. Do they just go bad sometimes?

[Greatscott]

You can figure out the voltage by counting the cells. Fully charged, each cell provides 1.2v, a 6 cell will be 7.2V, a 7 cell will be 8.4V. This is for NiCD and NiMH. LiPos are 3.7V per cell, a 2S will be 7.4v, and a 3S will be 11.1V. (A little help if my LiPos #'s aren't right, just getting started with Lipos).

I charge all sub-C (stick pack) batteries at the mha rating. So, if it is a 3300 mha battery I'll charge it at 3 amps, but you should be able to push it to 5 amps without a problem.

Are you running these batteries in a crawler, scaler, or a fast RC (Slash, E-Maxx, HPI...)?

Are you running the batteries until they dump, or are you running them until the RC can't move anymore? When a battery dumps you'll see a sudden drop in top speed, at this point you should stop running and change out the battery. Running a battery until the RC can't move anymore ruins the battery (it gets REALLY hot). I screwed up several sets of batteries when I first got my E-Maxx, I didn't know not to run them all the way down...

[davosfam]

I'm running them in a crawler, ax10 scorpion. Unfortunatley I've been running them until the truck stops or close to it. Won't be doing that anymore, thanks again for the advice!