Hi, Y'all,

I'm getting a little out of my depth, my last physics classes having been
nearly 40 years ago, but...


"Ken Heaton" wrote in message
news:xh05e.4996$VF5.1702@edtnps89...
Hi Skip, I'm looking at your math and trying to work out how you came up
with 170-125AH/day generated by your solar panels.

I'm not so much doing that as passing on the conventional and experienced
(that is, by folks who have SPs installed) wisdom that one may take the
wattage of current technology solar panels and divide by 3 (typical) to 4
(cloudy, etc.) for a real-world daily AH result. Not having same installed
on our boat (where there will be minimal or no shading), I can't do more
than speculate.


Will this 500 watt panel array ever actually put out 500watts? Or, as you
said above, will it really be only a quarter to a third of this ? If so,
how many hours a day will this panel put out this kind of wattage?
Perhaps
a couple of hours on either side of noon with diminished output before and
after this time?

500 watt panel /14.5 volt supply = 35 amps of current.

Ah - but I'm going with the higher voltages, for a couple of reasons.

One is easier transmission - smaller wires - for the same voltage drop.

The other is for more flexibility when tied to an MPPT. Typical peak
voltage would be in the 30s. So, presumably, at least, more amps result.

A third of this is only about 12 amps or so. For about 4 hours is 4 hours
x
12 amps = 48 AH per day. Perhaps you will get some useful power out of
the
rest of the available daylight, perhaps another 22 AH or so, that still
only
gives you 60 AH per day or so, no? Which doesn't seem to come close to
filling your anticipated daily power budget, let alone leave anything to
replenish the batteries from the drawdown on cloudy days.

Agreed. However, that (your scenario above) would make for a very small
output. I believe the 3 or 4 divider isn't at any given minute - else, why
would they be rated at any given wattage? - but, rather, a full-day
experience, ameliorated by darkness, clouds, shadows, and other impedimentia
to a 24-hour, full output, result.


Perhaps I've missed somthing here?

I dunno - perhaps *I've* missed something in all the research I've done. I
could swear that various posters to these fora have provided real-world
experiences on which I base my assumptions, backed up by various vendor
claims (as taken with the requisite grain of salt).

That I'll be in the Caribbean has got to help, too, but it's not the
presumption with which I started.

L8R

Skip, home for a couple more days before - this time - a 4 week working
visit to the boat-on-the-hard

--
Morgan 461 #2
SV Flying Pig
http://tinyurl.com/384p2

"And then again, when you sit at the helm of your little ship on a clear
night, and gaze at the countless stars overhead, and realize that you are
quite alone on a wide, empty sea, it is apt to occur to you that in the
general scheme of things you are merely an insignificant speck on the
surface of the ocean; and are not nearly so important or as self-sufficient
as you thought you were. Which is an exceedingly wholesome thought, and one
that may effect a permanent change in your deportment that will be greatly
appreciated by your friends."- James S. Pitkin