I have an Arduino developed AVR circuit inside a project box that is going to be battery powered (DSLR intervalometer) and i want to put 4 x AA rechargeable batteries (2700mAh or something like that) inside the box to power the AVR and the LCD.
I am looking for a schematic for a simple battery charger circuit that I can use to plug into my project box, via a jack plug, to charge the batteries inside.
Simple question, before worrying about recharging those batteries - have you successfully run the project assembly from 4x rechargeable AAs
Generally 4x NiMH AAs are likely to deliver less than 5v ...
Recently, I was reading ladyada's description of getting a regulated 5v supply
out of 2x AAs. For more battery duration, I suppose you could do that stuff with 2x2 AAs (two parallel stacks of two batteries in series). I like the way she brings her unit to a usb socket, making it easy to power (or recharge) anything that expects to plug into usb. Hmmm.
She describes the whys and wherefores here http://www.ladyada.net/make/mintyboost/process.html
As an alternative to AAs, though Mike justifiably says Lithiums have been
difficult, I believe there are now fairly economical ICs that will look after their charging process. (And Lithium cells do provide more stored energy in less weight.
Lithium charger chip example http://www.sparkfun.com/commerce/product_info.php?products_id=674
And breakout board http://www.sparkfun.com/commerce/product_info.php?products_id=726
And there is even a compact Arduino-compatible board that has the facility already on-board. Just directly plug in the (lithium) battery. Recharge via usb or a charger that looks like usb... And using such a board could make economic sense rather than adding a separate charger. http://www.sparkfun.com/commerce/product_info.php?products_id=8957