ProtoDAC TDA1387 X8 project

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There is a chance of cell imbalance in a 2S series configuration during discharge, so it is best not to push them to a near discharge state without a balancer circuit. The voltage will drop rapidly below 6.0V for the 2S. When charged, the cells will rebalance.

A BMS will turn off the entire 2S battery when one of the cells reaches the low voltage threshold. I do plan to add the BMS, and see if there is an audible difference with the added resistance of the switching MOSFETs.

Some data: Freshly charged batteries at 3.52V Time 0: 6.95V with Kali/ProtoDAC. About 6 hours later it was still in the plateau region at 6.53V. Each cell 3.28V. 11 hours 6.41V (6.45V unloaded = 3.22V and 3.23V).

Note: I have previously run RPi2/Kali/ProtoDAC on 1200mAh LiPO with LT1963. Based entirely on a seat of the pants comparison with the LiPO, I don't think these 2.0Ah labeled LifePO4 have that actual capacity.


                                 Typical LifePO4 state of charge profile