# COMMUNITY : FORUMS : TECH

## Alkaline Charger

So, I want to try and build a charger for alkaline batteries with an Arduino.
I'll be using it to recharge 9v batteries.
What I want to know is:

What would the optimum charge current/voltage be?
Should I pulse the charge current?
How do I detect the state of charge?
How can I get ~1.6v from the arduino to charge an AA? Can I use PWM 5v?
And any other useful info you may want to add.

I have a ton of parts/shields/etc for arduino as well as components.
LCD's, IC's, LEDs, diodes, resistors, crystals, etc.

Would also like to do a battery diagnostic utility to test health, resistance, charge, etc.
Can anyone help?

EDIT: So I made a quick circuit and sketch to charge an AA battery to 1.6v, using an LM317 adjustable voltage regulator. As os so far, it is working.

Now I need to figure out how to make a voltage doubler. I'm thinking something like 40-50 mA output at 10v.
I have an LM324N quad op amp chip as well as one of these. How could I make a doubler circuit?

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masterleo3 years ago

I saw a Video on youtube from 'incroyables experience" chanel who did this project !
and here on

http://en.wikipedia.org/wiki/Recharging_alkaline_b...

you can learn how charge Alkaline COMMON batteries SO,
we may use low current 10 mA and 1,5 V an a pause during 30 % of the time

Orngrimm4 years ago
I once also tryed that... Was a terrible mess... If they didnt got warm, they leaked... Acid or something alike... Stained my container (Metal) quite fast...

Best thing i was able to achieve was to top up the battery a bit if i used it some time... Lets say from 60% full a charge to maybe 70%... But recharge a dead battery to full: Nope. Or at least in my long trys i wasnt able to do that.

Whats the method of charge? CC? CV? Pulsating? Intermittent pulse with relieve-discharge?
How do you want to sense if the battery doesnt accept more chatge? DeltaU? I-sens with trigger?
LiquidLightning (author)  Orngrimm4 years ago
I charged up some batteries and finished with this project lol. I used an LM317 adjustable voltage regulator with a series resistor for a 60mA charge current, and used an Arduino to monitor and terminate the charge. So CC/CV. Arduino just checked if the voltage was at the alkaline full voltage, I think it was 1.55v and it would terminate the charge.
LiquidLightning (author)  LiquidLightning4 years ago
OH, and I used a transistor switch to pulse the charge current at 150Hz.
mpilchfamily4 years ago
Are you trying to recharge regular alkaline batteries or ones that are actually made to be rechargeable?

If your looking to charge the non-rechargable kind then stop right there. While you may be able to get some to charge, most will overheat and burst open on you. It's really not worth the trouble.
LiquidLightning (author)  mpilchfamily4 years ago
The batteries will be in an enclosed container with a thermal fuse to prevent overheating.
steveastrouk4 years ago
What has your detailed research so far yielded you ?