6 volt solar panel linking

First off, props to Ken for holding down the forum while I was visiting home for the holiday.  Ken is right on the money on this one. 

Like he said, it is easiest to turn everything into watt-hours.  That way your equation uses the same units all the way through.  If you know how much you use per day, you can then figure how much you need to produce and store. 

1. To figure out loads, use a kill-a-watt meter to measure power and energy, and input data into a load calculator sheet.
http://store.altenergystore.com/Meters-Communications/Meters-Battery-Monitors/Power-Meters/P3-International-P4400-Kill-A-Watt-Power-Meter/p932/
http://shop.altenergystore.com/Calculators/OffGridCalculator.html#

End up with watt-hours per day figure

2.  To figure out average daily solar production, take rated watts by the sun hours in your area.  For example a 100w module in a place with 4 sun-hours per day would make 400 watt-hours per average day, wink-wink.  we usually take off 25% for inefficiencies, so I would count on 300 watt-hours.

Daily solar production MUST meet or exceed daily energy usage if you are only using solar, and you want your system to work.

3.  To size battery bank, turn batteries into watt-hour values.  For your case, 2 batteries in series makes for double the voltage (12v) and the same current.  So, at 216ah, times 12v = 2592 watt-hours of storage.  But you can only use half without hurting them. 1300 watt-hours.  This number must meet or exceed your usage total.  you then increase the battery bank based on how many days of storage you want without sunshine.

I've reached my typing patience limit, but check this out if you want to learn more in depth.

http://store.altenergystore.com/Books-Seminars-Videos/Solar/Photovoltaics-Design-Install-Manual/p481/

hope that helps

- james Alt-E staff