On 19 May 2015 at 04:23, Jason White <whitewaterssoftwareinfo@gmail.com>
wrote:

> The DIY way of providing an well isolated power supply would be a
> small solar cell and a bank of high intensity LED lights.
>

Highly inefficient - but

of course efficiency is not too important if massive isolation is achieved.

The very best LED's are over 50% efficient (light energy out)/(electrical
energy in)
Assume 25% is practical.
Module output efficiency of readily available PV is say 15%. (Usefully more
with Sunpower rear contact cells but 'annoying' to work with)

So IF you can get all LED energy onto the panel and evenly enough
distributed that differential effects are minimal you get
0.25 x 0.15 ~+ 4%.
If the insolation on individual cell surfaces is uneven then the lowest
current output cell sets the string current.
Getting all the light evenly on the whole active PV surface is
'challenging' at least.
50% of best case should be doable so say 2% overall.

So you can expect ~=3D 20 mW of output per Watt of LED input with good
quality components and careful implementation.

Leading edge single cell crystalline silicon PV (still "off the shelf) and
top LEDS (off the shelf but top flux bin and you'll have to twst their arm
or cherry pick them yourself from a mixed bin batch) and very careful
optical design may get you 10% overall or 100 mW per Watt. In most cases 20
mW/W will be acceptable.


            Russell
--=20
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