Electriceddie

Hi Guys,

I am a long time RC’er with Glow but I am new to electrics. I have a New (but small) Great Planes Electric Evader Jet with an 14.volt 2200mAh ElectricFly battery powering up the motor & the radio. I noticed that the sides of the battery are puffed out just slightly. Kind of like there was a little air pumped into the opposite sides of the battery. The battery is only about 8 months old and never used in flight and works fine when I run up the motor. I charged it and discharged it maybe 3 or 4 times it the last month or so and it seems to work fine. In fact I took the plane out this past weekend for its maiden flight and it flew very well after I got it trimmed out. I flew it for about 5 or 6 mins and brought her in. I made a trim adjustment and a Throw Rate adjustment and went back up again. After about 4 mins of flight while running at wide open throttle the motor abruptly pulled back on its own. I raised the throttle and it took off again and it happened about 45 seconds later. If I am correct this is the electronic speed controller kicking in and warning me that the battery is getting low? Is this correct? And is the slight puffiness on the sides of the battery anything to worry about?


Thanks

Ed

Rob2160

Hi Ed,

There are a few things you can do to ensure good battery life from your LiPo.

1. Never store them fully charged,
2. Don't discharge them beyond 20% capacity (That means you should only be putting back around 1800 Mah into your 2200 Mah battery after a flight)

Puffiness is not a good sign - if the battery is 8 months old and puffing I would suggest replacing it.

Also best practice is to fly to a timer that prevents the ESC Low voltage protection from kicking in.

It depends on the the low voltage setting in the ESC but generally if you fly until the motor powers down you have already drained the battery too much and this will ruin it very quickly.

For example - I have a plane that will fly for 8 minutes at full throttle before the ESC low voltage protection activates - I always fly that plane to a 6 minute timer and land - this gives me plenty of buffer and the battery is never discharged too much.

RustyUs

I would increase the C rating on you next battery pack so that the battery won't have to "work" as hard; thus reducing the chance of "puffing". I have used (2) 2S 4000mah 25C in a 1/8 scale truggy and they were always hot and the case(s) were always swelled. After ruining 4 packs, due to cracked opened hard cased LiPo batteries ("puffing"), I switched to 40C packs and the LiPo batteries temperatures went way down to normal (barely warm).