# Aa Battery Charger

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## 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. :-)

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## 7 Discussions

I'm using a battery pack from a Xbox controller
And a USB cable I got the red wire on the positive spring and the black wire on the negative spring....my question is do I need to flip my batteries so that the positive side touches the red wire or vice versa?

What would be the power requirements for charging 6 Rechargeable (1.2v) batteries.

Never is a word that should "never" be used on here. A warning, precaution, or "be freaking careful" is much more appropriate on instructables. "Never" suggests something may impossible. You may have started a fire but you learned that the way "you" did it was wrong and your comment should be....don't do it this way because this may happen and explain. Clearly there are ways to recharge AA 1.5V batteries and to do so safely. Even your "failed" method may be safe if done outside in a ventilated and cooled location so if it did catch fire it wouldn't cause damage. Charge them under a charcoal starter so if they burn up you don't need a match and paper. To everyone..."We need people to tinker and fail because failures lead to solutions." Fail safely though because as a paramedic and a "tinker" I've seen repeatedly what stupid is and what stupid does. Stay safe and fail often.

Alkaline batteries even on switching mode tend to pop, the chemical makeup does not like to be recharged. In the early 90's tomy came up with a battery charger that did pulse switching and a rudimentary feedback to tell when the battery would no longer hold a charge. These would work on alkaline as well as ni-cad. Battery manufacturers threw a hissy fit stating that they would be put out of business. Tomy quietly dsicontinued making these, they are now worth their weight in gold. But switching mode is still wonky for recharging alkiline's though.

The SMPS I used was modified, I installed a smd timer chip to charge for 30 min at a time and cool for 1 hour and the battery's charge to 1.5 volts just fine just barely getting warm. :-)

I try to avoid being critical, but I will say that it is NEVER a good idea to try to recharge alkaline batteries. They can leak acid, explode, or start fires. There is a reason that all of them say "Do not attempt to recharge". They do not recharge effectively, and are incredibly dangerous. Even rechargeable batteries should always use a proper charger. LiPo batteries will start on fire if overcharged, lead acids leak hydrogen and oxygen gas (I've had one pop a cell while charging before. It's not a good thing to be around). I almost set my basement on fire once by voltage going back into some alkalines. They leaked, smoked and melted the container to slag.

I try to avoid being critical, but I will say that it is NEVER a good idea to try to recharge alkaline batteries. They can leak acid, explode, or start fires. There is a reason that all of them say "Do not attempt to recharge". They do not recharge effectively, and are incredibly dangerous. Even rechargeable batteries should always use a proper charger. LiPo batteries will start on fire if overcharged, lead acids leak hydrogen and oxygen gas (I've had one pop a cell while charging before. It's not a good thing to be around). I almost set my basement on fire once by voltage going back into some alkalines. They leaked, smoked and melted the container to slag.
"Injury or extreme pain" isn't an overstatement. Don't "recharge" alkaline batteries.