Its a pelican style case, with a 1000w charger that can charge the chemistries i listed above. I built a nice charge case that I use all the time. If you buy a hobby grade charger, (the ones for rc cars, and helicopters) you can make tons of different connectors and charge all kinds of batteries (pb, NiMH, NiCd, Lipo, Life, Li-ion) not alkaline because it's generally not safe and if you charge them with a charger for alkaline (one that pulses the battery hundreds of times a second at about an 80% duty cycle) they only charge a handful of times. Most button cell (cr2015, cr2030 i think those are their designations) are lithium, and 3v per cell. On the output, I have added a PWM circuit with 80% duty cycle. I use my lab current source adjusted to 40 mA. I have found recently this possibility to charge alkaline batteries. Charging will last few days, but you will lower a risk to damage a battery.
So if you use a serial diode, apply resistor closest to 37 Ohm. Calculate a resistor to limit current to 40mA as, R=1.5V/40mA = 37Ohm. So calculate voltage difference as V=3.7V-1.5V-0.7V = 1.5V. In that case, we have additional voltage drop on a diode of 0,7 V. You can add serial diode to protect reverse current. Limit your current to 40mA, so calculate serial resistor as R = 2.2V/40mA = 55 Ohm. To charge one battery from 3.7V, calculate voltage difference as V = 3.7V-1.5V = 2.2V. So possibly it will charge your battery with 1A and that is bad. It means at >300mA it will overload, overheat, and output voltage will drop. If adapter is rated 3.7V 300mA, it does not mean it will limit current to 300 mA. With a better circuit, you could automate the on/off cycles to charge them up.ĭo not used adapter directly connected to a battery. I've just started experimenting, but I was able to get enough charge in two completely dead batteries to start up my power-hungry Canon digital camera and take a few pictures (with screen and flash) and turn it off without it dying on me (died the next time I turned it on). Repeat this a bunch of times to get the charge up. After they have leveled off (usually around 1.5V) put it back on the adapter for another minute or so. Because of this, you have to disconnect the batteries frequently to let them "cool down" (though they usually don't even get warm, the voltage will quickly drop down to around 1.5 V after disconnecting). The voltage on the batteries will go up quickly, but the actual amount of charge will not. With that sort of current, you shouldn't leave the batteries connected very long at a time. Many people have developed fancy charging circuits, but I was able to get charge into some Alkaline batteries with just an old cellphone plug. Did you know that you can recharge alkaline batteries? Well, they're not perfect (don't have very good recharge capacity, few recharge cycles, etc) but you can recharge them to an extent.