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Charging batteries via a 5v USB connection

I am working on a project that requires 4 AA batteries. I would like to discuss if it is possible to create a charger that would charge the batteries (rechargeable AA's of course) via a 5V USB cable. The unit itself would not need to use the 5V USB power to operate, just to recharge the batteries when not in use. Does anybody know if this is possible? Please let me know if this a vague question, as I am in no means a professional in this area. Thanks in advance to any insightful comments!

honduhridr (author) 9 years ago
well, time for charging is not an issue. Thanks for the comment. I have a friend who is an electrical genius, so I will pass this on to him. See if he understands it. Thanks again! Another possibility is to use the power from Playstation 2 controller as this is for a Playstation 2 project. By an off chance, nobody happens to know how much power the Playstation 2 unit is providing the controller do they?
http://www.hardwarebook.info/Sony_Playstation_Controller_Port

heres a pinout of psx, might be the same for PS2 since you can interchange controllers. I suggest putting a voltmeter to it, it sould be 3 or 5 volts. If your really new to electronics you put the black end on pin 4, the red end on pin 5.
honduhridr (author)  guyfrom7up9 years ago
yeah, saw that already. I have been doing my homework on this and come to find out, the PSX controller port also has a 9V pin that is usually not used for the regular controllers. According to the pinout that i found and the pinout from the link you provided, the 9V pin is #3. I actually tested it with my voltmeter and it is indeed the same with the PS2. 9V. I have been thinking about it though. When the unit is not being used the PS2 will be turned off, so no current will be present in either the controller port or the USB port. I think i might just gut a standard 120V wall battery charger and somehow work it into what i am using. I don't want to overuse your knowledge, but do you happen to know how a battery charger works? I am pretty sure i cannot just connect the battery terminals on the charger to the battery terminals on my unit, or can i? I guess what i am saying is, am i able to connect the ends of the charger (the guts from a standard 120V AA battery charger) to the same connections as the unit draws its power from? (god i hope that makes sense, it does to me, but I am the newby here. :-) ) Thanks again guyfrom7up!
guyfrom7up9 years ago
you could charge 4 AA's by USB, but it wouldn't be a beginners type of circuit, and it would take possiably almost 24 hours to fully charge. So yeah... I'm just getting my figures from a 2400mAh battery, 500mAh usb port, you have to step up the voltage, so lets say 300 or 400 ma, 2400 x 4 = 9600, 9600/400 = 24