Minimum battery discharge C rating

[Foamforce]

I’ve built a mini scout with an 1806 2280kv motor, a 12a ESC, and 6x4 prop. I’m planning to run a 2s battery. From what I gather online, this setup should use about 10a.

I have a little 350mah 25c battery. So I take 25x.35=8.75a right? So this battery can’t supply the full 10a, only 8.75a, right? So if I run this at WOT, will it ruin the battery first, or will it cause a failure in the ESC or motor somehow? For additional fun, the load wires on this battery look very thin, maybe 20ga. So maybe those would melt first? Will I have a flaming meteor plane?

So then the sanity question, if I were to run a 450mah battery on this plane, to calculate the discharge rate needed, would I take 12a / .45 = 26.66? Should I add 25% overhead to that as well, so maybe I should be looking for at least a 33C battery?

Thanks!

 

[XSrcing]

If you ran at WOT throttle for the entire flight you would puff the battery. If you are flying like a normal person it will be just fine.

You are way overthinking this part of the hobby. Yes, lipos can be dangerous, but this amount of worry over <2 amps is overkill.

 

[Tench745]

The closer your amp draw is to the C-rating, the more voltage-sag you will get and it is harder on the battery. You're trying to pull power out faster than the internal chemical reaction of the battery can provide it. This will limit the performance and flight times you get at full throttle and damage the battery over time. If you undersize the battery it won't hurt the motor or ESC in any way. If it's way undersized the voltage-sag could be enough to cause a brownout at full throttle, but I don't think you're risking that with your current setup.

XSrcing is right that it will only really matter when you're flying near full throttle, but if you want your battery to last, increasing size and/or C-rating is the way to go. As for how much you need, you have the math correct. In my opinion there is no need to add the extra 25% margin as you already factored in a safety margin by using the 12a draw instead of 10.

 

[XSrcing]

Don't let this be the excuse that stops you from flying!

 

[Foamforce]

Thanks for the help! I’ll go ahead and fly it. The battery is a cheapo $4 one, so it’s fine if I ruin it. I want to be able to fly the plane inside at a local event that has a 6oz limit, and I’m currently just over that at 6.2oz, so I’m figuring out where I can skimp without actually turning it into a flaming wreck. It’s good to know that I’m not likely to do much worse than kill a cheap battery.