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Hey Guys,

I have this schematic for a AA battery USB charger I built. I am wondering what I need to do to put rechargeable in the unit, and charge them in the unit.

Thank you in advance,

Robert

https://www.circuitlab.com/circuit/2b2c3z/aa-switching-charger/

@rjojjr91,

You have already asked this question and had some feedback:

https://www.circuitlab.com/forums/power-electronics/topic/j377fm95/aa-powered-usb-charger/#comment_4720

This may not have answered your questions but similarly you have not provided any further information on which to base any more helpful responses.

In your two postings you have said:

"I am putting together a USB charger powered by 8 AA batteries ... what would I need to integrate to charge the AA's if they were rechargeable?"

"I have this schematic for a AA battery USB charger ... what I need to do to put rechargeable in the unit, and charge them in the unit."

You need to clarify these statements.

If your charger is powered by 8xAA batteries how do you expect it to be of any use to charge AA batteries? You might as well just buy/make a mains charger and charge the AA batteries that you're then going to use in your USB charger that runs off 8xAA batteries.

Except that 8xAA primary cell batteries = 12V but that would require 10xAA NiMh rechargables @ 1.2V/battery.

Also, your circuit claims to be a USB charger.

So what exactly is it charging?

Your questions seem to be circular and may imply that you are attempting to build a perpetual motion machine ...

... using rechargable batteries to charge rechargable batteries to drive your charger that runs off rechargable batteries ....

BTW: the link you have posted to your circuit does not work.

it will work on 12v input but can you explain How does goes to the Output.

@Geoffry,

The link you have posted to your circuit now works but shows a basic 12V to 5V step down switch mode PSU circuit using an LM2575 "simple switcher" from TI.

It appears to run from 8*AA rechargable batteries and drives an unspecified load.

This is not an AA battery charger circuit nor is it suitable for use as such.

Attempting to use this circuit to charge NiMh batteries could result in serious damage to the batteries and injury to the user.

I suggest you read up about:

charging NiMh batteries:

http://en.wikipedia.org/wiki/Nickel%E2%80%93metal_hydride_battery

and the LM2575 device:

http://www.ti.com/product/lm2575

@Geoffry,

Sorry about the confusing post above: I tried to delete it. CL went through all the steps of deleting it but then didn't actually do it.

:(

This is how I should have introduced the above post ...

The link @rjojjr91 posted now works but shows a basic 12V to 5V step down switch mode PSU circuit using an LM2575 "simple switcher" from TI.

:)