View Single Post
  #4  
Old March 19th 12, 07:16 PM posted to rec.aviation.soaring
Darryl Ramm
external usenet poster
 
Posts: 2,403
Default Glare shield solar cel

On Sunday, March 18, 2012 6:41:32 AM UTC-7, N2 wrote:
Anyone have a source for flexible solar cel that would fit on /over a glare

shield?
Al


What is it you are hoping to do with this?

The thin film/flexible/amorphous solar panels typically have significantly lower efficiency than crystalline silicon based panels (e.g. as used in Strobl panels for mounting on gliders - even factoring in the low fill factors of Strobl type panels). And that is before mounting them behind a canopy where they will be less efficient (maybe as low as 10% reduction up to much higher numbers just from absorption by the plastic, but good luck finding spectral efficiency specs for commercial solar panels, and the efficiency is also reduced from the solar panels getting warmer then they might if outside the cockpit as Bumper points out). A significant factor in reducing the practical power available is just simply the solar panel is not oriented towards/tracking the sun, resulting in the panel providing a lot less power than the specs might imply. Solar panels mounted on the glider have the same issue - but at least those panels can be relatively large and usually have fairly high efficiency.

I've seen small solar panels mounted over a glareshield, they are typically just not enough power to be significant in flight and sometimes the goal appears to be to trickle charge the ship batteries for gliders that are left tied down out in the open... but VRLA batteries have such low self-discharge rates they don't need to be left on a trickle charger, and as far as re-charging batteries goes its usually better (to avoid sulfation damage to the battery) for VRLA batteries to get them fairly quickly back to a significantly charged state than leave them out hoping they will trickle charge say over a week or two off a small solar panel. and for glider left tied down, you are probalby better off protecting the cockpit interior and/or canopy with either internal or external canopy covers.

Darryl