Today I made a battery top-up bank for all my rechargeable batteries, because that way I always have a number of charged batteries available.
First I use the Bm110 charger to refresh NimH and NiCad batteries and the BT-C3400-Battery charger to prepare the Li-Ion batteries to about 50% and then keep the topped up with this battery charging bank.
I wonder if there's something like that somewhere available? Although, since my knowledge of electronics is only at hobby level, maybe you got some better ideas on how I could improve it.
Topping up Li-Ion batteries:
Li-Ion batteries last longer on a max. 60% charge I read. That's why I BT-C3400-Battery charger measure their capacity, then charge them to about 50% and use a timer to keep them at 50-60% charged.
Topping up AA +AAA NimH and NiCad batteries:
I bought a number of these Universal chargers and leave the batteries in there, because when they are charged the charger turn off and when the voltage drops they automatically top-up the batteries.
Topping ul NimH and NiCad batteries packs (= 3V6 to 10V8 packs):
First I fully empty the battery pack via a lamp or resistor and then, use a 12V/1A power supply to fully charge the pack until it gets quite a bit warm and then use the top-up battery bank to keep the batteries topped up via a 12/1A + 5V/3A power supply and the timer. Each connection to each battery pack feeds some 200mA current via a diode and a selected resistor. I guess with daily 10Min charging time I should keep them all topped up.