Lithium Polymer Troubles

Blacksails

Blacksails

Member
So like an idiot I accidentally flew a set of storage charged batteries and not my fully charged ones (dont ask how).

The packs are 5s Gens Ace 5500mah 25C. And I've depleted them to 16.6v..........unloaded!

They were only very slightly warm, and were instantly put in a fridge when I realised my mistake.
The charger (Cellpro powerlab 8) is charging them at 1C OK, and the resistance in each cell seems to be as they normally are (around 3 ohms). They haven't finished charging yet, so I don't know if they're still taking full capacity.

Have I been lucky and are they OK? I was always told damage occurs in lipos in the form of higher resistance, and my resistance readings haven't changed.

Blacksails.
 

kloner

kloner

Aerial DP
Generally speaking, this is like running a a car out of oil. it may still seem right, but i'd be vary cautious over the next few cycles. i might even run those cycles on the charger and just let it take the abuse if something is wrong then re-read the ir. if it's damaged what you should notice is a rapidly increasing ir and less and less mah going back in. if you fly past that line because it las less volume than expected, that's usually a 100 ohm ir a cell immediately after, smokin hot, puff, not square corners anymore

usually after a cycle on the charger it'll tell you how many mah it took last and note that number each time. You should see 100's of mah reduction a cycle if done on a charger with a few amp load. i've seen up to thousands of mah reduction on 5000 mah packs before but i also thought it was going to combust
 
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Blacksails

Blacksails

Member
Thanks Kloner

Balls, looks like they're knackered.

Charger is reading 47% capacity and its only put 1700mah in. 47% should be around 2450-2500mah
 

kloner

kloner

Aerial DP
try a few cycles but there not self healing. They may still work, but you might want to use em around ground equipment that's not vital if theres such a thing. Starters, tv's, lighting, etc
 

Lanzar

Lanzar

Member
16.6 is above 3.3v per cell so u did not damage them, they shoul be fine.
dont worry, just do 3 cycles on charger and back on.
 


Blacksails

Blacksails

Member
So, after a few cycles these batteries are still averaging around 1.3 ohms per cell on a full charge, have no puffing, and are still taking 95-100% of their capacity. Can I deduce that they are safe to use as normal?

I was sure I had damaged them as they were 16.3-16.6v after I landed, and right as the craft was about to touch down there was a loss of power.
 

kloner

kloner

Aerial DP
try em, but be aware your "testing" something so keep it low, close, etc. Run them a few cycles and note any changes tow hat you just mentioned. starts heading south, you know what you got. nothing worse than ignoring it then to later crash because of it. Been there done that
 


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