link to a pic of a case like i allready have:

www.richmondcamera.com/v/vspf...-2T.jpg

hey zippy thanks for the input, i have not pulled the trigger on lead acid batteries yet but it looks like i can buy 12v 7ah batteries shipped for 14.00 on ebay, i was leaning toward either 4 or more of them to use in my setup. they weigh about 2.5lbs each. cost is part of the reason, do you know where i can get liion batteries for this project? i also need to know how much power my 20 watts of solar will generate so i can determine how many amp hours to make my battery bank.

HI DAN!
ok let me start over,
i have 2 of these:

High efficiency module---17.25% Mono-crystalline Silicon
Low iron tempered glass
Suitable for prolonged outdoor use, water proof
EVA laminate and TPT backsheet
Anodize aluminum frame
Bypass diode minimizes power drop by shade
10 years limited warranty of 90% power output and 25 year limited warranty of 80% power output.

Specifications:

Maximum Power: 10.3W watt
Maximum-power Voltage: 17.8 volt
Maximum-power current: 0.58 Ampere
Open-circuit voltage: 22.1 volt
Short-circuit current: 0.69 Ampere
Size: 350 x 285 x 18 mm ( 13.8" x 11.2" x 0.7" )
Weight: 1.25 KG (2.8 pounds )
Surface of the cell: 125 x 125 mm
Temperature: -40 ° C / +80 ° C
Temperature coefficient of Pm (%): -0.47 / ° C
Temperature coefficient of Im (%): +0.1 / ° C
Temperature coefficient of Vm (%): -0.38 / ° C
Tolerance: + / -5%

mostly for form factor (they fit in the openings i want to mount them in nicely). I only use a few usb run gadgets 5v 2a or less amperage each so no worry on the power needed, basically my question is this: because i own 2 of these panels allready and they fit my project form factor nicely, what is the most appropreate sized battery bank for 2 of these panels. i only want to discharge what i can pay back on a sunny day AND i want to only discharge the reccommended amount, what is it like 40%?