I have a 2 cell Lipo 7.4 V 1200mA and a 3 cell Lipo 1.1 1500mA pack, ...can I connect them in parallel without messing up My esc? My 30A mini ESC tends to overheat , is this do to the fact that my Twin 600 demand too much?
This is my first electric and it's starting to make me go kookoo...
Thanks pier

No, you can't connect those two batteries in parallel. To connect batteries in parallel, three things must be true:

1. They must be the exact same voltage and capacity.
2. They must be in the exact same state of charge.
3. They must be roughly the same age.

If you connect those two batteries in parallel, the higher-voltage battery will overcharge the lower-voltage battery, causing it to get hot and possibly catch fire.

With the 30A ESC and two 600 motors, you're probably overloading it. Each of those motors is probably drawing 20-25 Amps. A little simple math will tell you that 40-50 is greater than 30...

Matt,

pigi412 had emailed me the same question and I guessed that the higher voltage battery would try to charge the lower voltage battery.

Just curious why you need batteries of the same age. Is it for capacity reasons (declines with age) and the danger over over discharging the older battery?

Thanks.

Thanks guys.....
I did have a feeling it didn't work....anyhow there is no hurry since I wrecked my dornier 228 this morning after a couple of runs...Fortunately it's nothing bad.
I agree we the overload theory since I had a series of overtemp shut offs....the last one during take off even if it was a cold cold morning.
Thanks again...it's all good experience and electrics have hooked me.
Ciao from Rimini, Italy

I've always thought it was a good idea that the packs be as similar as possible. Packs that have been subjected to different amounts and different types of use/abuse have different performance and charging characteristics. Being in parallel should mitigate some or most of that, but you never know.