Hello,
I wish to install a rechargeable system on my arduino project. I have 4xAA case and i would like to bridge it to a USB outlet that can feed and recharge those 4 batteries.
Any advises on how to do it ? may be a scheme or an already experienced ?
Please .. send me your ideas
May be I will direct the question differently :
What about soldering an USB outlet ( 4.75 / 5.25 V.) straight to the +/- of the case containing 4xAA rechargeable. Will this function ?
thank you
Don't solder directly between the USB and the battery case as you will probably damage the batteries and maybe the USB.
What type of batteries are you using (NiCd, NiMH, LiFePO etc) this will determine what charging system to use.
It is not easy to charge 6 volts of batteries from a 5 volt supply. It can be done but it is challenging.
Perhaps your batteries are closer to 1.2 volts each instead of 1.5 volts each. Perhaps your battery case allows access to two batteries at a time. Perhaps you are capable of building a buck-boost power supply.
More information is needed.
Okay, so we know your using NiMH batteries now, so the next question is do you want to plug the thing into power when discharged, charge the batteries as fast as safely possible and then disconnect it from power or do you want to keep the thing connected to power all/most of the time so it acks as a backup power supply.
If you want to plug in, fast charge & unplug then you will really need to use a proper charging device (or build one) as you will destroy the batteries if you overcharge them with high currents.
If your thing will be plugged into power most/all of the time then you can probably use a simple current limiting (constant current) circuit to keep the charge current down below a level that wont destroy the batteries if left charging for a long time but it will take a lot lot longer to charge the batteries when they are flat.