Arduino with Lithium/Solar

Background:

I call it the security bot. Its a Arduino with a camera and motor shield. It will be controlled via a website so I can remotely roam the house. Maybe in the future it will roam by itself and add more sensors to it.

I am using a XBee connected to my computer to control it since WiFi uses to many pins.

Currently using serproxy(tinker's version) and PHP to control it via a basic page. The camera is being served with Activewebcam.

Using the Adafruit motorshield connected to 2 hobby motors.

Currently testing with 4 AA 2650mAh batteries. I need to come up with a solution to power it as long as possible.

Was thinking of a 6Ah battery and using solar to continually charge it during the day from a window.

Parts List: Battery: http://www.sparkfun.com/products/8484 Charger: http://www.sparkfun.com/products/726 or http://www.sparkfun.com/products/8293

They have 2 solar panels I could use or some from dealextreme.com

The idea is for me to remote control it when I am away whenever and not worry about charging and such. Granted most of the time it will be idle.

Question:

I know I need to figure out what my current requirements are but is there a better way for longer term power or will this work?

I am thinking to use 2 step up dc-dc to take the batteries 3.7 to 5-6v for the motor shield and another step up on the same battery to 8v for the Arduino and camera(camera is 5v but has IR which don't turn on at 5v needs 8v or maybe my current isn't enough). I am pretty sure I will be under 1A, right now though the motor cause the 5v+ to drop below 5 which causes the camera to turn off.

I know that I could have 2 power supplies but with the limited space and charging requirements I don't see how I can do that.

I have a transistor to control the power to the camera so that it isn't on all the time unless someone is connected and turns it on or could be based on battery level or motion. I have the Arduino sleep after 5 secs of no serial activity.

I was thinking I could even shutdown the XBee if the voltage gets low and wait for it to charge up.

A friend was thinking to use a inductive coil to charge on a pad. Or a dock of some kind that you can drive up to charge.

Any ideas? This is my first Arduino project, probably a little big for a first, but I learn fast.

Maybe in the future it will roam by itself and add more sensors to it.

It'll be able to use a soldering iron? Impressive.

Have you checked out how much current your solar panels are producing and how long your battery takes to charge at that current? You find that data in the data-sheets provided with both. If you have troubles interpreting them, make a sub-project to learn to read and understand data-sheets. Without that skill, you project is doomed to fail.

Also, if you happen to live in a place that isn't as sunny as California or Nevada, better check how many hours per day your solar cells are going to produce power for you.

It's the small details that foil cunning plans.

Korman

Thanks I have been looking at datasheets. I actually live in CA but I am thinking that it still will take to long to charge. I did find a 6v 330mAh solar panel at adafruit, but for 6Ah it still will take forever.

So looking at inductive charging or some kind of dock. The dock is probably more efficient.