L-16s like higher voltages [RE-wrenches]

[Allan Sindelar]

----- Original Message -----
From: "Ray Walters" <remotech at taosnm.com>
> I found 2 major problems with the Sandia study:

I appreciate that Sandia is trying to provide usable technical information
to the public. But I sometimes find their information incomplete,
impractical, and sometimes incorrect.

Incomplete: several years ago they compared the effectiveness of small
charge controllers. The results indicated that some CCs did a better job
than others--but as a government agency, they couldn't or didn't publish
which ones worked better. Now they suggest that some batteries work better
than others, too ("Results vary significantly for different manufacturers.")
"Gee, thanks, folks, I'll go right out and buy some of the better or worse
ones today!"

Impractical: 3-6 hours/week of generator finish charging. 'Nuf said.

Incorrect: A few years ago I was talking with an engineer at Morningstar
(John Doty, I believe--no longer there) about ways to improve the Prostar.
(The Prostars we sell are usually installed by the user as a replacement for
something that died.) I was complaining about the automatic default to gel
setpoints on any power-down, and suggesting a jumper (a la SunSaver) or a
switch on the back. I told him that virtually all of our small home systems
used flooded batteries (golf carts), not gelled. He said that this was news
to him, as he thought most off-grid home systems used sealed batteries. I
asked him where he got the information that led to that conclusion, and he
said it came from a Sandia study some years back on battery types in home
systems.
Then a couple of years ago, at a Dankoff dealer training, the author of that
study was a speaker. I asked about that conclusion re sealed batteries.
Turns out he had sent a questionnaire to PV distributors, asking them what
types of batteries they sold. Bingo--considering that PV distributors sell
sealed batteries that can ship, and battery distributors have truck delivery
routes to deliver flooded batteries that can't ship, we all saw immediately
how the man from Sandia reached his conclusion. Ask the right question if
you want the right answer. Or, as I recall from the early days of computers,
GIGO--garbage in, garbage out.
Allan at Pos En

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