do Li Poly batteries self discharge
 

I started to fly my electric plane a few weeks ago and decided to pack up and go home. The wind started gusting up to 25 mph and I didn't want my 1st flight using electric equipment to be done in a hurricane. I am an experience flyer but didn't know the actual power of the electric gear I have since i've never flow with electric before. The battery pack I'm talking about is a Zippy 20C , three cell 2650 Mah. Its been about 5 weeks since that happened. Will the battery still have its full charge or will I have to re-charge it? If in the event I do have to re-charge it, will I have to cycle it down or what is the procedure?

RE: do Li Poly batteries self discharge
 

They do not self discharge, but topping it off can never hurt. You do not have to discharge a lipo to top it off.

RE: do Li Poly batteries self discharge
 

Do not cycle lipos.

As said, Lipos discharge very little, but a top up charge jsut before you fly is always a good idea.

RE: do Li Poly batteries self discharge
 

Yes, they do self discharge but at a very low rate. Since man has not yet invented a perfect insulator, all batteries will self discharge with the rate determined by the quality of the insulation between the plates and contamination between the two poles.

RE: do Li Poly batteries self discharge
 

Thanks for all the quick responses to my question. I appreciate very much the ones that took the time to answer my questions. As I've said before, theres a wealth of information on batteries all over the internet, but digging out the information as it pretains to me can mean hours of scouring the posts and threads trying to find my specific inquiry. Thanks Rodney,Aeajr and Barracudahockey.

RE: do Li Poly batteries self discharge
 

Answers something I've pondered over. I find a day after balance charging to 4.2 per cell a day later they will measure in the range of 4.16 to 4.18 per cell. They appear to level off at that range at least for a few days. Topping them off only puts 30 - 40mah back in a 3 cell 2200mah pack in my case, so hardly worth it IMO.

RE: do Li Poly batteries self discharge
 

I believe that the lower resting voltage after charge is due to higher internal resistance. As the battery ages, IR goes up and you can see this during the charge cycle where you reach CV much quicker. Since the charger will not exceed 4.2v per cell, and part of that potential is dissipated by the IR, it stands to reason (at least to me!) that the battery will come off the charger at a slightly lower voltage.

My tired 10S packs will be 41.7v after resting off the charger but the lower cycle batteries will maintain 42v.