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Battery discharges very fast

#1
I'm having trouble with a battery discharging way too fast on my tricopter. It flies for a few seconds but then doesn't have enough thrust to stay in the air. The battery goes from 4.2 volts per cell to 4 volts per cell very quickly. I'm pretty sure it's just one battery. I've marked it to make sure the problem is just with one battery and not all of them. My question is, could this be due to a short somewhere in my wiring, or just a dead battery? I did just recently switch flight controllers and the problem started the first time I tried my new Flip32+. However, when I switch to a different battery, the problem seems to go away.

Is there any quick way to check for shorts without re-wiring and desoldering the whole thing?
 
#2
It could just be a bad one from the factory. What brand is it? Some brands are just lower quality in general. Have you ever charged it at high than 1c or over discharged it?
 

ZoomNBoom

Senior Member
#3
The battery goes from 4.2 volts per cell to 4 volts per cell very quickly.
Which shouldnt come as a surprise. Here is a chart I pulled from google:

FVG29GEHY12L22N.LARGE.jpg

Notice how, if you pull any non trivial amount of amps from the battery, say 10C in the above example, it pretty much instantly drops to 4v (and well below 4v if you pull more amps). That doesnt mean there is a problem, thats just how lipo's work.

With a higher C rated battery (or larger capacity), the drop may be less pronounced, but it will always be there, and from 4.2 to 4v will always represent only a marginal percentage of the battery capacity. And voltage will drop under load, if it doesnt, you have a too high C rated, ie, too heavy, battery.