Hey i got a question about running my lipos parallel in my mini revo. I have two common sense RC 2000 Mah 10C discharge lipos. It seems as when i run them in parallel it runs faster then when i run it with just 1 lipo. Also when i run in parallel each pack is much more cooler, when i run one at a time the temps are noticeably much warmer. I know parallel double the Mah but not the voltage. Does running it in parallel also double the discharge rate? I know 10C is low for the Mini Revo. Also would using a lipo with a higher discharge rate run faster?

The load of the motor will pull the voltage much lower than the batteries rated voltage. So when you run 2 in parallel the voltage to the motor will be higher than with 1 battery since the load is being shared by 2 batteries and not pulling the voltage as low. Also when running in parallel each battery is not working as hard, so the batteries run cooler.

There are a few different ways you can look at this issue. Think of voltage as something that gives your motor its speed. But current is what gives it the muscle. Think of the old axiom "Many hands make light work".

Your motor/prop combination seems to be telling you that your single LiPo's capacity (10C) doesn't have enough muscle (current) to spin the prop as fast as it could. With two LiPo's in parallel, your motor goes faster because it has more power to give to the prop. And yes, as you note, more capacity gives longer runs. If you were to run your motor without a prop (not recommended) you would see no difference in RPM whether you were running one, two or twenty batteries in parallel because the current draw is so low. I suspect that if you were to add a 3rd LiPo you would probably not see any additional increase.

You are right about higher voltage (i.e., running in series) making the motor run faster. If you were to increase the cell count but not the current, you would get more prop speed flights would be shorter.

A single higher discharge rate battery (with the same capacity) would also run the motor faster but again, the motor runs would be shorter.

Just remember not to exceed your motors power capacity, and make sure that your ESC is up to the task of more current

I hope I made things clearer and not cloudier with my rambling explanation.

Bob

Putting your batteries in parallel has the same effect as using a battery with only half the internal impedance. Result: cooler running and a higher current due to less voltage drop in internal impedance.

Ahh thanks for clearing that up, now it all makes sense [8D] So if i can, should always try to run them in parallel?

Not necessarily... the trick is to find a single battery that will suit your needs. I used to run two 4S 2100 mAh's in parallel but, as someone pointed out to me, what about when one pack starts to lose more capacity than the other as it ages? Then charging and running (discharge rates) could be a bit different. That's not to say that you shouldn't use them, just that in the future it would be better to buy a single battery rather than two in parallel.

I was able to switch to a 4S 4200 mAh and the setup is so much easier. Simple is better in this case.

See what your motor wants in terms of the number of cells and current.

Bob

Yeah i bought both packs at the same time and have ran them all the same amount of runs. My mini revo has two battery slot's, and many people run in parallel or run in series with an external lvc. The lvc is set at 3.6v on my stock esc and when i check the volts on both packs their always at 3.6v-3.57 depending on if i run it after the lvc kicks in.

1 pack for jumps, less weight.
2 packs for general driving lasts longer.
With 2 in parrallel the system can draw an extra volt, so it may seem a touch faster with 2 in parrallel.