I was searching for something like that ereyesterday. Couldn’t find anything aside from maybe Xtar BC4 which is a battery charger with power bank function, but even if that works properly, it’s going to be not very useful capacity-wise.
I have one of those 4xAA power banks from AliExpress, but it quickly drops voltage way too far. It’s fine for USB LED lights and running my USB fan for 5 hours (with some old NI-MH batteries I have), but it won’t charge most things due to the voltage drop. One more problem is the series connection. Weaker cells can get reverse-charged and damaged during discharge.
I was searching for something like that ereyesterday. Couldn’t find anything aside from maybe Xtar BC4 which is a battery charger with power bank function, but even if that works properly, it’s going to be not very useful capacity-wise.
I have one of those 4xAA power banks from AliExpress, but it quickly drops voltage way too far. It’s fine for USB LED lights and running my USB fan for 5 hours (with some old NI-MH batteries I have), but it won’t charge most things due to the voltage drop. One more problem is the series connection. Weaker cells can get reverse-charged and damaged during discharge.