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HobbyKing: LiFEPO batteries not showing


#21

I have just ordered one of these (certified genuine) to go with the new LifePo batteries also just ordered. I will take care to test the cells before doing anything else after unpacking them.

The old LiPos have swollen and the cells no longer balance nicely. They don’t seem to have lasted very long. I suppose they have done a couple of hundred activations between four of them so that is only 50 each :frowning_face:

73,
Rod
Thanks for helpful comments above.


#22

It’s not yet Advent but an order to Santa for a LiFePO cell and genuine IMAX B6 has been placed.


#23

Well my swag arrived sooner than expected and everything seems to work. I do feel a little overwhelmed having gone from a simple fixed balance charger that no options (connect it, light flashes till battery is charged) to an IMAX B6 which has lots and lots.

My question is simple: for a 4200mAh LiFePO cell, what charging current should I use?


#24

I have an iMAX B6AC and 4S2P LiFePo4 batteries and I set charge voltage at 13.2V and current at 1.0A
Never had an issue with that.
Good luck!
73,

Guru


#25

I always use 2A. I can’t remember exactly why I chose that value when my battery and charger arrived from HobbyKing, but a couple of years on and the battery seems to be happy with it…


#26

My packs have occasionally suffered from stuck cells on both charge and discharge cycles at higher charging current. I sorted it out by letting them rest and reducing the charge current. Just something to bear in mind.
73 de OE6FEG M0FEU
Matt


#27

Hi Andy,

Most manufacturer’s data sheets recommend 0.5C (ie about 2A for your 4200mAh battery) for the constant current part of the charge, with a maximum of 1C .

HTH :slight_smile:


#28

I always do a balanced charge for the LiFePO4 batteries, but occasionally one cell will not reach full charge at the same time as the others. What I do then is discharge them down to 3.3v each and then charge them again. This seems to occur when the battery has not been used for a while, but I find this usually cures the problem.

Although my charge current is set at 2.0A initially it drops as the cells reach their end voltage, sometimes to as low as 0.1A. When the charge current is as low as this it takes a long time to bring up any cells that are lagging.

73’s
David


#29

Hi to all,

While viewing this thread, I checked out the Hobbyking UK site.
I bought the ZIPPY Flightmax 4200mAh 4S1P 30C LiFePo4 Pack a couple of years ago.
There are 2 versions of the ZIPPY Flightmax 4200mAh battery, the 4S1P 30C (1 Piece) and the 4200mAh 4S2P (2 Piece). I bought the 4S1P 30C as it weighed slightly less at 512g versus 558g of the 4200mAh 4S2P.

However, the 4200mAh 4S2P version is on offer at the minute with a discount of £13.98, may be of interest to anybody making a purchase.

Here are the links :


Regards,
Martin


#30

I spotted the reduction in price on that pack the day my box of new swag arrived :frowning:

I consoled myself over the £14 saving by thinking that a 4S2P has twice as many cells as a 4S1P so is twice as likely to fail :slight_smile:


#31

And its 46g heavier!


#32

The 2p versions have parallel cells. Thats fine while they track well but once a cell deteriorates, it seems to me the good cell will always be charging the bad one and that surely signals the early end of the pack.

For this reason I have avoided the 2p format.

Andrew VK1DA/VK2UH


#33

I read somewhere that the charge current should be less than or equal to 1C. I usually use between 0.5C and 1C.