Introduction: Aa Battery Charger
This charger can charge rechargeable AND alkaline aa battery's. (If you want to charge other batteries you can but the have to be 1.2-1.5 volts each, you can charge a total voltage of 4.5 volts max! If you charge higher voltage you may damage the charger!)
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Step 1: Warnings!
1. If you try to charge over 4.5 volts with this charger you may damage the charger and/or your battery's!
2. If you use a charger over 800 mA you may damage your battery's!
3. If you try to charge battery's using a linear charger/wall wart, the battery's may explode or leak and/or cause damage to the battery's, wall wart, yourself or pets! Do NOT use a linear wall wart!
Step 2: Finding a Wall Wart
When looking for a wall wart, look for a SMPS or switching mode power supply. They are really common so it should be easy to find.
Step 3: Find Battery's
You can charge a wide range of battery's as long as the total voltage doesn't exceed 4.5 volts. If you want to charge battery's from 9.0 volts to 11.5 volts you would need a 12.0 volt SMPS wall wart. Note: if you use a 12.0 volt charger you will NOT be able to charge batteries below 9.0 volts! Do at your own risk! May result in injury or extreme pain! In my case I just want to charge AA battery's so I'm using a 5.0 volt charger.
Step 4: Voltmeter
This is optional but if you have a multimeter or voltmeter use it. This is to check the battery voltage before and after.
Step 5: Find Battery Holder
You can use any holder that will hold your battery's and you must be able to solder to the terminals. I got mine from a push on light from the dollar store.
Step 6: Solder Together
Solder the wall charger to the battery holder, note polarity!
Step 7: Insert Battery's and Test!
Insert the battery's. Then plug in and test. Charge time may vary from 30 minutes to 6 hours, depending on what battery's you charge, the capacity of the battery's, the number of battery's, and how dead the battery's are. Enjoy and be patient even though you think the battery's May not charge. :-)