[Soekris] Sanity check a solar/battery setup

[Christopher Hoover]

> So the question is:
> Is the 18w solar panel (it's mounted on top of the vehicle and sits in 
> a full sun area) going to be enough to power the CarNetrix, the GPS 
> module, and the 4521-receiving EVDO and pumping WiFi, without dropping 
> the main battery below 11V figuring avg 10 hours "on" for five days at 
> a time?

The back of the envelope math is pretty easy on this.  You have a 
certain amount of charge in the battery.  You are going to draw a 
certain amount out at some rate (charge/time => amps).  You will replace 
a certain amount at some other rate.   Typically you do battery 
calculations in units of A*h (equivalent to 3600 coulombs, the SI unit 
of charge). 

-ch