For a project of mine, I'm making a battery pack that disconnects the internal battery after switching to an external battery.
I'm a bit worried about parallel charging lead-acid batteries that are at different voltages.
Doesn't it create big currents between the batteries without the diode? I don't want to waste battery energy charging the internal battery with the external one.
Here below is the schematic. A charger and two batteries automatically switch between each other when external battery is plugged in.
Should I be worried about the currents between the batteries or are there things I'm missing?
EDIT:I've made a newer schematic and added a relay to bypass diode D2, we run on the internal battery until the external one is plugged in. Whenever the charger is plugged in it bypasses D2 and can charge both batteries battery. imgur.com/a/RQGyYy5
