I've put together the following circuit, it's just a rechargable LED torch, just to try load sharing:
BAT1 is a LiPo battery, 5.2 V comes from the AC adapter when the thing is being charged. There's a charging circuit connected, but I'm using a module, so I couldn't include that in the schematic, but I think it should be irrelevant as the battery is basically disconnected in this configuration.
The voltage drop on D1 was around 0.2 V, but the voltage between V1 and ground was around 3.9. The battery was at 3.7-3.8 V at the time, but like I said, it should be irrelevant.
- What am I missing? Where could that additional 1 V voltage drop come from?
- Is my battery safe, and completely disconnected from the load?
- Can you recommend a test setup so I can check this without actually using a LiPo battery?
It is entirely possible that I've messed up assembling the circuit, I'll probably build another later anyway.