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A123 26650 Lifepo4 charging
#1
I made a 14S charger using 14 tp4065 with 14 isolated power supplies. This will top balance a 14s Li ion battery pack using the balance connector.

I tested a 26650 Lifepo4 cell on a single tp4056 charger with a diode in line on the + output. The diode is dropping .6 volts measured.

The cell charges to 3.6v then the blue charged led lights up.  The tp4056 still keeps supplying a very small ramping wave that keeps the red charging light flashing rapidly. The ramping voltage is trying to start a charge but goes off due to no current flow as the cell is at 3.6 volts. The ramping voltage is maybe 2% pulse width and .1 volt above 3.6v at that power level a 10ah group of cells will take a year to charge to 3.7v.

Anyone using a modified tp4056 to charge 3.6v cells?

Started off building a 18650 battery for scooter, then changed to a 26650 lifepo4 build so had a charger already made for the 18650"s.
The discharge current of the 26650 is a crazy 50a per cell, I won't need more then 30amps. But it's nice to have extra if needed.
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#2
Have you verified that each of the TP boards cut in/out at the same exact voltage? Those boards have about 1% variance, so they could be as low as 4.242V - 4.158V. It would not be good if 2 of them are at the extreme of that range.
I would recommend possibly changing to TP5100 as they are more energy efficient and they can take a higher input voltage. This means that you can use 12V instead of 5V to power them. This makes them more efficient as they are a buck type converter, not a linear regulator. They don't get very hot when operating at full charge.
However, don't 2s those boards without the necessary update changes to them, if though they are supposed to be 2s capable.
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#3
Korishan Wrote:Have you verified that each of the TP boards cut in/out at the same exact voltage? Those boards have about 1% variance, so they could be as low as 4.242V - 4.158V. It would not be good if 2 of them are at the extreme of that range.
I would recommend possibly changing to TP5100 as they are more energy efficient and they can take a higher input voltage. This means that you can use 12V instead of 5V to power them. This makes them more efficient as they are a buck type converter, not a linear regulator. They don't get very hot when operating at full charge.
However, don't 2s those boards without the necessary update changes to them, if though they are supposed to be 2s capable.

Yes each board cuts off at same voltage. I had a few that over charged and under charged but were culled from the batch.
I wanted a balanced charge so I figured to charge each bank with its own charger, but I have a active 1.2a 16s balance board and a 16s bms on the way. I will charge with a 58v charger and monitor the cells to see how balanced they are. If I don't like the results then I will proceed with the single bank charger. May go with the tp5000 or tp5100 for the lifepo4 charge voltage, but I already had the tp4056 on hand.
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#4
Queen Battery QB26650 2300mAh should be marked as a 2800mAh one. It's a fantastic cell! It costs twice less than the 2500mAh model and 3 times less than ANR26650M1B. Queen Battery warns that these cells should not be connected in series of more than 4 cells and the total number of cells in the pack should not exceed 60 but i don't know the reason of such a warning. QB26650-2300's IR is very stable and there won't be problems with extreme disbalancing. Whatever, I'd highly recommend this cell as a very low-price LiFePO4 cell with excellent performance!

cps test
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