Robot Solar Power

Doing some research at Arizona Wind and Sun... ( on 6 Jan 2002

Looks like generally, $5/watt for the usual panels. The flex panels from Solarex are as low as $4.39/watt, but the Unisolar ones are $12/watt. Output is around 120 W/square meter for the fixed panels, 47W/square meter for the flex panels (a heck of a lot less efficient!)

The real problem seems to be that the bigger panels (75W plus), are all 1.2 meters long or bigger. No problem when bolting it to your roof, a big problem on a 1 meter long rover....

I wonder if you can redesign the panels a bit.....

Make/Model Price dimensions Mass
Rated I Rated V Voc Isc
Siemens SP75(single crystal solar electric panel with 36 cells) 409

(thickness includes junction box)

7.6 75 4.41 17 21.7 4.8
Siemens SP100 (discontinued!) 478 1498x594x56 10.9 100 5.9 17.0 21.6 6.5
UnisolarUSF32 Flexible 298 1430x424 2.14 32 1.94 16.5 27.1 2.4
Unisolar USF11 149, 2/280 554x424 0.91 11 0.62 16.5 27.1 0.78
Solarex Millenia 43W 189 ? ? 43 ? ? ? ?
Kyocera KC80 389 976x652x52 9.6 80 4.73 16.9 21.5 4.96
Kyocera KC120 598 1425x652x52 11.9 120 7.1 16.9 21.5 7.45
BP/Solarex SX-120 598 1456x731x50 12.8 120 3.56 33.7 42.1 3.87


Individual Cells

Astropower ( has a eval kit for $185 that has 20 AP105 cells (5" single crystal, 2.1 W) which is: 40W, or about $4.60/watt (pretty high, considering you can get a whole panel already assembled for about the same..)

The Solar Cell Company ( sells 4" cells, 0.9W for $1.95, or 36/$64.75 (which is about $2/Watt). Kind of a cheesy web site, but heck, they're in the business of selling solar cells, not web design. (114W/square meter of cell area) has some interesting analysis and a handy calculator showing that All Electronics cells SPL-22, which are 10 for $5 are not such a bad deal. 20mm square, .45Voc 100mA Isc (the catalog shows V@I (simultaneous), but hah, we know better). ANyway, they're up in the big 0.12 mW/mm2 clump (120W/m2..), and give 90mW/$. Interestingly, this is $10/W... The SolarCell company selling the $2/0.9W cells is a much better deal on a W/$ basis,


There's a fair amount of literature on the web about using a concentrator with a cell. Even a flat plate mirror can increase the output (never as much as the whole area), especially when you have a fixed orientation panel. And, mirrors are a heck of a lot cheaper than cells.

robot/solar.htm - 6 Jan 2002 - Jim Lux
robot main page - Jim home page