Goal is to be under commercial price and last 20+ years.
AFAIK the low end commercial price for a low weight foldable 50-60 W panel with charging electronics combined is near $300.
AFAIK other flexible panels can be bought for cheaper (e.g. >100 W for <$150) but they are much heavier and will only roll up into what appears to be a 4-6" diameter cylinder. DC-DC converters not included.
Thus, this project aims to be under $150, not counting labor (or fun) of course.
breakdown of expenses:
- $49 – 10x 6.2 W amorphous silicon solar cells (total 3 pounds)
- $75 – encapsulating polymer materials: FEP front sheet film ($40), EVA encapsulant ($15, but TPU or TPO might be better if you can find them), TPE back sheet ($20)
- $17 – voltage conversion parts, misc electronic bits and pieces (under a pound)
- $15 – 12V 5A-hr sealed lead acid battery (60 W-hr, 3 pounds)
- $25 – tarp and contractor's clipboard (to store the solar panel)
total cost: $181, but the tarp and contractor's clipboard could fairly easily be replaced with free or nearly free parts, bringing the total cost down to only $156. This compares very favorably to commercial options ($300+) if you have the time to spend on this kind of project.
total weight: well under 10 pounds? not so bad!