I found a little dump-load / charge controller on Ebay.
UNIVERSAL RELAY DIVERSION CHARGE CONTROLLER REGULATOR - eBay (item 130409810996 end time Jul-20-10 04:14:47 PDT)
It seems to be made to monitor a 12V battery (tied to PV or wind) and if the battery
gets up to the 14.3v 'Charged' state,
User Settable Dump/Diversion/On-Off Voltage Set-point (13.1 to 15.1 Volts)
It will turn on a load relay or SSR to discharge the battery a little.
See Solar hookup diagram here:
http://www.windandsunpower.com/Downl...RDC_Manual.pdf
Anyways, I was brainstorming
and came up with the idea that I could
put four or five 12V batteries in Series. To be fed by my 65-70 volt PV..
70v of PV / 5 batts = 14volts each..
AND, the little Ebay board could monitor
just one of those series batteries!
But, when it switched on a fat SSR, it would be connecting not just 12v,
but the whole series string of batteries to the load!
The board could be adjusted to trigger at 13.5 (67.5v of PV w/ 5 batteries),
which should be near the sweet spot and maybe give a quick 455w
jolt to the 10 ohm load.
And then, I snapped out of it and said, 'I can't afford 5 batteries right now'!
Then, I started thinking about 5 big capacitors in series!!
If they were matched, wouldn't they act like a voltage divider-battery string??
Then, I said.. Do I really need 5 caps? Wouldn't one big cap work?
If I put a pot across it? With the output tap set to 13.5v, when the cap
was at 67.5v?
I'm liking this idea, because caps will charge up Faster than batts..
And, the SSR will be cycling faster, delivering the jolts of watts/BTUs,
as fast as the PV can supply them. (Depending on the clouds)..
So, what do you guys think of my crazy ideas?
Cheers,
Rich