Self Regulating micro PV system [RE-wrenches]

[Allan Sindelar]

My 1991 Siemens product line spec sheets include the M65 and M35 as 30-cell
modules with square cells. The M65 is 18.0 voc, 14.6 vmp at 25C. "With 30
cells in series, the high efficiency Siemens M65 is a 43 watt self
regulating solar electric module. Self regulation eliminates the need for
separate charge control devices, resulting in a simple, reliable and
economical power generating system." NOT!

The Arco Solar cut sheet from 1985 is worse: "The M65 is engineered to take
advantage of the natural compatibility between the electrical
characteristics of solar modules and specific storage batteries. Like a
finely tuned charge controller, the high efficiency M65 regulates its
electrical output to the needs of the battery being charged."

Allan at Positive Energy

----- Original Message ----- 
From: <joeldavidson at earthlink.net>


> Summer 1982, at the request of Arco Solar I tested their 30-cell modules
> and reported that the M61 did not charge batteries in summer due to low
> voltage and, without a charge controller, could over-charged batteries in
> winter. Unfortunately, Arco marketing had already decided to roll out the
> 30-cell module. Some of you may remember this was the same time that Arco
> pushed the Delco 12-5000 15% d.o.d. battery as the right battery for
> off-grid systems. Several other PV techs reported that the 30-cell module
> and 12-5000 battery were bad ideas, but Arco management and their in-house
> techs toed the party line to the bitter end. A few years later, the same
> Arco people claimed that they developed the "improved" 36-cell module.
>
> Original Message:
> -----------------
> From: Bob-O Schultze, Electron Connection econnect at snowcrest.net
>
> Dan and All,
> So called self regulating PVs were and are a cruel joke. Less than 36
> cells just means the power levels roll off sooner and hardly work at
> all in lower light levels. Yet, a 33 cell module still has enough
> voltage to overcharge a full battery. That's probably why nobody
> makes the culls anymore. I don't believe I've ever seen a 30 cell PV.
> Use a CC.
> Bob-O
>
> >I saw this in an old Siemens installation instructions, If you wish
> >to use a pv module on a wet lead -acid ( I am para-phrasing now),
> >they recommended  a panel with now more than 30 cells in series -
> >lower rated voltage - and to make sure that the maximum charge rate
> >for the panel to the ampere-hour rating of the battery bank in
> >question was a C/200 rate or less
> > In R. Perez's classic "Complete Battery Book", (TAB Books), I
> >also believe he says something similar, that's where I  1rst saw a
> >rule of thumb guide for self regulating batteries with a PV module.

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