My lipo battery is hard-wired into my circuit. The battery itself has a DW01A battery protection IC on it. Here's what I see happen.

* The circuit running on battery power (no USB) runs its voltage down to 2.4 V when the overdischarge protection kicks in. The BAT+ and GND in my schematic at that point read 0V because the DW01A mounted on the battery itself opened the circuit
* I then plug in USB power, supplying the TP4056 with power which I expect to start the battery charging process
* The battery charging doesn't start

One of my question is why? I think it's one of two things or both:
Idea 1: The circuit to the battery is still open because the battery itself hasn't recovered back to the overdischarge release voltage of 2.9-3.1V. Chemically speaking it just may not which is concerning because then the battery itself couldn't ever recover given its hardwired in.
Idea 2: The TP4056 can't recover a battery that is < 3.0 which is the trickle charge threshold voltage.

So what do I do to resolve this? I only have a few ideas:
1) Implement an over-discharge circuit myself that interrupts at 3.1V which is greater than 3.0 which is the claimed maximum of the trickle charge threshold voltage of the TP4056. Further voltage drop below 3.1 would be minimal (DW01A and other IC leakage currents), when plugged in the TP4056 would have a closed circuit to work with since the DW01A wouldn't be in overdischarge mode, and the TP4056 will begin charging since it's higher than its trickle charge threshold voltage.

2) I have no other ideas lol.

What should I do here?
Any example circuits I can look at for this problem?

 

I learned a few things.

The DW01A CE pin which is connected in the on-battery protection circuit is for "charger detect" according to the datasheet. Indeed when I manually gave that pin 5v from the power supply the overprotection circuit disengaged. By that point the battery had naturally recovered from 2.4V when it engaged to about 2.88V so it stayed disengaged.

However, the TP4056 still did not begin charging. Probably because it's not at the trickle charge voltage which is expected to be 2.9V or could be as low as 2.8 and as high as 3.0. I suspect if the battery recovers enough to get to 3.0V the TP4056 will start charging it.

So a TP4056 and a DW01A are just not a good fit together. That's surprising to me. Many many lipo batteries come with a DW01A battery protection and the TP4056 is (as far as I can tell) the most common lipo charging IC there is.

To then provide my own battery protection that turns off the lipo battery at 3.0V I think I need to look for an IC like the DW01A just with an undervoltage protection at 3.0V instead of 2.4V. Also I'll likely need the dual channel mosfet also for it to provide circuit interrupt.

Any thoughts are welcome.

 

Well I found the reason. The TP4056 was either dead on arrival or died somewhere along the way. The issue here is that the TP4056 won't charge at all lol.

If I switch to another board, well everything works fine. Yes the DW01A goes into lockout at 2.4 V, but the undercharge lockout unlocks as soon as the power is applied to it.