"Walt" wrote in message ...
Im not sure the MPPT controller allows for higher voltage/smaller wires.
PV arrays are to some
extent constant current and a "12 volt" array will put out its maximum
power at a voltage
typically higher than the battery. So if you hook the array up to a
battery with a "cheap"
controller, it is basically a direct connection and the PV current stays
about the same but the PV
array voltage drops to the battery voltage so you can lose a fair amount
of delivered power. The
MPPT controller allows the array voltage to operate for maxiimun power
while supplying current to
the battery at the batteries charge current. I have a 160 watt pannel
(2x80w Kyocera) and
typically I might have 8 amps comming out of the panel and maybe 10.5
going into the battery (the
currents will of course vary all over depending on how much sunlight,
angle, ect).

Also, the MPPT charger I have (Blue Sky - company used to be called RV) is
intelegent about
properly charging the batteries which can make them last longer. Ive only
had this product for
several months but think it was a good investment.

wh

Blue sky was the make my installer (svhorizon.com, KISS US distributor)
recommended. It was his suggestion that I go to the higher voltage panels in
order to make for smaller wires possible with the same voltage drop (thus
the need for MPPT). As much wattage as we'll have, and as far as it has to
run to the ER, after the trip down the (tall) arch, drop is of concern.

Unfortunately, they're driving to the Oakland show and won't be available to
start on the project for nearly a month. Then, I hope to get the electrical
stuff buttoned up quickly, as I have what is now a very short window to get
the boat finished before my surgery.

L8R

Skip


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Morgan 461 #2
SV Flying Pig
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