So I decided I had to use polycarbonate or acrylic sheet for the job. I heard stories about acrylic sheets melting in heat, solar cells getting destroyed by moisture etc. But I still decided to go ahead with it because it was the simplest, strongest and safest encapsulation I could think of.
The panel cost me around $35 to pack 22 3"x6" cells (.5V x 3A x 22 = 33W). The whole setup can be folded and connected in different ways to charge Li-Ion, SLA or NiMH Battery packs.
Step 1: Things needed
Optix Acrylic sheet: $28 (32x44inch sheet) cut into 4 - 16x8 sheet and one 1 16x12 sheet. Picked this one up from Lowes and they were kind enough to cut it for free. Thanks Lowes!
Silicone sealant - $6 (This one is from GE and is flexible, clear and cures in 24 hrs)
Rubber electrical tape (optional).
Small 3/8" tile spacers ($2 for a pack of 100).