Cordless phone batteries to power tracker

[ericw]

Has anybody experimented with the replacement cordless phone batteries at Radioshack? They seem like a cheap way to place rechargeable power into the tracker to power the micro controller and gps... 10$ to 25$

Here is what I'd like to build:
12VDC from vehicle -> 12-14VDC converter to about 5V -> Rechargeable cordless phone battery -> Tracker power inputs
12VDC from vehicle -> Car power adapter for C168i phone -> C168i phone

What are the intricacies of attaching a rechargeable battery to a constant power source? Will it burn it out? Do I need some electronics in place to charge these batteries (an oscillation of current or charge/discharge cycles or something)? I've never worked with batteries like this but I know it can't be this easy.

Eric

[Mike]

Yes it will ruin the battery if you don't have a charge controller.

You can wire the tracker into the cellphone battery.

The tracker battery lasts months unless you leave it in continuous tracking a lot of the time.

Mike

[ericw]

So you're saying run wires from the power terminals of the cell phone's battery to the tracker power input and then just use the car charger to keep constant power to the whole setup?

That seems like a great and simple solution, I'm going to try that out.

Eric

[ericw]

My car chargers for the c168i phones just came in the mail today.
They were a dollar a piece and contain all of the charging circuitry/battery saving hardware.

Not very professional looking to glue onto a circuit board, but cheap and great for hobby purposes...

Cheap phone, cheap charger, cheap micro controller.... the only expensive part of this is the GPS chip and antenna!

Anybody know of a cheap GPS product that could be cannibalized?

Eric