Time Pilot

I have a 7C Cheap Battery Packs 1150 mah 2/3 A Nimh with Ultra Deans connectors that looks like is on its way out after 80 flights. Would this be considered a poor, average or good lifespan for a flight pack?

I log my flights so I know that it:

Has 80 flights on it averaging 16 minutes,
therefore has been discharging for for just over 21 hours at approximately 4 - 5 amps.
It's been charged at 200mA on a Great Planes AC Park Flyer charger.

Thanks.

JoeAirPort

My Feedback: (41)

I was waiting for people who knew more about batteries to answer this. But since nobody did I'd say it is not normal. Especially since you charged it at such a low rate. Now if you discharged at a higher rate than it can handle that might be a reason. If the battery is selected and used properly it should last you years.

Time Pilot

Thanks for taking a crack at it, JoeAirPort. I actually have two of these packs and the other one, bought at the same time, is tired too.

With this one particular pack though, I took off and landed right away because I thought I had put a discharged pack in it. Not the case. I took it home and charged it. I put 130 mAh into it even though this pack was fully charged 4 hours earlier.

Anyone else?

BillS

I think you will find that battery packs are good for 500 plus discharge cycles. Packs go bad for all sorts of mysterious other reasons than discharge cycles.

Bill

Time Pilot

BillS,

I have 4 of the same pack. The two I bought first are both tired compared to the new ones. I thought I'd get more cycles out of them too. Makes me think maybe I should have spent the extra few dollars and got the GP cells rather than the house brand.

BillS

Cells without a manufacturer’s name and capacity are likely rejects from a production run. The rejects get into the black market and the unscrupulous sell them as good product. You might want to check for name and capacity. The packs that I have made from unmarked cells always measured less mah than rated capacity. Makes me uncomfortable.

Bill

Time Pilot

Thanks, BillS.

If cycling my battery doesn't revive it, I'll take off the shrink wrap and look at what's under the wrap.

I will update this thread in a few days after the cycling. Takes a while with a 1150mah pack at .2A discharge and .1A charge!

marcellus

Buy cheap - buy twice they say. In 20 years flying nearly all my unmarked/unlabelled cells have failed faster than those labelled Sanyo and so on. There is a major UK Distributor whom supply unmarked cells and they are just not worth having...

Time Pilot

Test results are in.

After cycling the battery 4 times (200mA discharge, 100mA charge), it is performing a bit better than it was before, but not great either.

I’m wondering if I could have done something to make them happier. I did usually fly them in my Estarter until they were showing signs of tiredness. I may have hit LVC a couple of times with a GWS ESC with a cutoff of 4.2V. I’ve always been nice to them charging. Never at 1C, a couple of times at C/2 and mostly at C/5….

Never-the-less, I think I'll be taking Marcellus' advice, Buy cheap - buy twice, and get a name brand cell next time.