I recently purchased the freeduino and have been wanted to do a project.
Project points:
test solar charging efficiency.
Read the voltage and current of a charging small battery (like in an ipod).
store these values and display them.
make this as mobile as possible. as i would like to record/test while walking (messing around with solar panels).
I have been doing some research online and what I have come across were mainly voltmeters on different microcontrollers an nothing on what im exactly trying to do, I was wondering if anyone knew of the best way to go about setting up the arduino as a voltage/current reader be able to store or print the results. Any guidance in the right direction for this project would be greatly appreciated.
If you want to measure current, you need some sort of sense resistor in the path. This could be a challenge if you have lots of systems you want to monitor: you need to either install one permanently, or disconnect the source and interpose one whenever you want to monitor.
These are rather nice (though a bit pricey) if you have a medium-to-large solar charging system to monitor. But note that they're unipolar, so you need separate sensors to monitor charging and discharging. phidgets.com has some bipolar ones, but they're even more expensive, and you have to have an analog input that can read negative voltages. There are less-expensive sensors available from Sparkfun (and, doubtless, others) for checking lower voltages and currents.
One thing you might consider is adding a "test port" to your systems, with a 3-pin connector for "source", "load", and "ground". You would normally put a "dummy" plug in it that shorted the source and load contacts, but pull that and plug in a "test" connector wired to your sensor(s) when you wanted to check on the system.