Re: Case mod feasible
Dear Breakable, The "Minty power" links at the bottom of http://wiki.openmoko.org/wiki/Battery demonstrates that building a 2 AAA battery pack USB charger is feasible. As 1.2 * 4 is almost 5, building a 4-pack would probably be simpler. You will probably want to connect a 47.5 kOhms resistor between the "ID" pin and the "GND" pin in the USB connector to identify it as a FreeRunner compatible charger. -- Minh HA DUONG, Chargé de Recherche, CNRS CIRED, Centre International de Recherches sur l'Environnement et le Développement http://minh.haduong.com ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Case mod feasible?
On Monday, September 22, 2008 15:39:24 Andy Selby wrote: > AAA batteries are 1.5 volts, so 4x1.5=6volts, if you find a diode that > has a voltage drop of 1 volt you won't need any voltage regulation > circuitry. > Actually, most AAA (and AA) rechargeable batteries are about 1.2 volts when full. -- Kelvie Wong ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: Case mod feasible?
> Basically what I want is to add 4 rechargable AAA batteries and plug that > into usb port. > That gives me about 1200ma at 4.8v, which should comply with the USB > specification (5v), AAA batteries are 1.5 volts, so 4x1.5=6volts, if you find a diode that has a voltage drop of 1 volt you won't need any voltage regulation circuitry. > This should avoid the requirement for sophisticated electronics, Voltage regulators aren't sophisticated, its just a VR chip and one, maybe two resistors for calibration. >Anybody thinks that this is not feasible or not worth doing for some reason? See my post here on batteries http://lists.openmoko.org/pipermail/community/2008-September/029965.html I got a battery and charger for under £8 ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Case mod feasible?
Hi, I am just thinking to do a casemod for Freerunner. Basically what I want is to add 4 rechargable AAA batteries and plug that into usb port. That gives me about 1200ma at 4.8v, which should comply with the USB specification (5v), would it not? This should avoid the requirement for sophisticated electronics, and extend the battery life to max 4x + 1 (the original battery). While not overloading the form factor too much. It could address the biggest issue in freerunner now - battery life. Anybody thinks that this is not feasible or not worth doing for some reason? PS:Waiting for the software to mature does not seem like a solution to me, I would wait for the technological utopia to materialize instead ;) Regards, Breakable ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
