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What capacity would you expect from a brand new lipo battery?

#1
Hi,

I have just bought zippy 1800mah/40c and a 1000mah/25c battery from hobbyking in the uk. I used my charger/discharger to take the batteries down to 3v then balancing both charging at C, neither battery balanced fully in 2 hours. The 1800mah showed 1650ma charge and the 1000mah showed a charge of 850ma. The same charger using the same process gives other packs that I have getting within 50ma of the stated capacity.

I'm wondering about sending them back! But it has made me wonder what capacity (or margins) would you exepct with brand new packs?

Thanks

nick
 

FastCrash45

Well-known member
#2
Hi,

I have just bought zippy 1800mah/40c and a 1000mah/25c battery from hobbyking in the uk. I used my charger/discharger to take the batteries down to 3v then balancing both charging at C, neither battery balanced fully in 2 hours. The 1800mah showed 1650ma charge and the 1000mah showed a charge of 850ma. The same charger using the same process gives other packs that I have getting within 50ma of the stated capacity.

I'm wondering about sending them back! But it has made me wonder what capacity (or margins) would you exepct with brand new packs?

Thanks

nick
It's telling you what you put into the battery. You can't get the capacity rating because there is always a partial charge unless the battery is at absolute zero. If your lipo ever gets to absolute zero it will be dead forever. Shouldnt discharge them lower than 3.2 volts. It's VERY hard on them
 

FDS

Well-known member
#3
If you went down to 3v per cell then the battery is now dead. At best you shortened its lifespan, at worst it’s permanently bricked. NEVER go below 3.3v per cell.
When you get lipo it is shipped at about 30-45% charge with a cell voltage of 3.6-3.7V per cell, this is usual for STORAGE settings on chargers or as sent by the factory. When you wish to use them you should BALANCE CHARGE at capacity in Mah divided by 1000. So an 850Mah battery should be balance charged at a rate of 0.85A. I am sure you have done this part correctly.
You should only keep packs fully charged for a max of a couple of days, so if the weather changes and you can’t fly, use STORAGE program or discharge to 3.6-3.7V per cell to keep them safe.
With the cells maxed (4.2-4.3v per cell) you should get full capacity at full charge. It’s likely that the smaller pack with lower rated cells in is damaged or now has a bad cell, you probably got away with it on the bigger packs.
The easy measure of how well a pack is performing is how closely balanced the cells are, you should be +/- 0.1v ideally, across all cells. If your charger allows you to read internal resistance then that’s worth knowing as cells age.
I don’t know where you are getting your lipo care info from, please stop listening to that source and DO NOT mess with the charger again until you have figured this all out.
The problem you will have in sending those packs back is that no UK postal service except I think UPS will take pouch cell lipo. I had two packs that I got wrong from HK, I just threw them away, it was cheaper than posting them back for a refund.
 
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