On Tue, 27 Jan 2009 00:41:37 -0800 (PST), 377
wrote:

On Jan 26, 4:21 am, BruceinBangkok wrote:
Larry, if you read this.

Am embroiled in a discussion about solar panel controllers.

Aside from the fact that smaller arrays of panes don't put out enough
amperage to over charge a medium bank of batteries, can you comment on
what type of regulator is usually best. I have seen both shunt
regulators and others that simply open either the positive or negative
leg between the panel and the battery, which seems a simpler method. I
have also seen a home-brew regulator the shorted the legs together,
but that seems sort of brutal to me.

It appears to me that a simple voltage sensor and a solid state switch
is all that is needed, but perhaps I can't see the forest for the
trees as regulators, over here, cost a hundred bucks, or more.

Cheers,

Bruce

My 2 cents worth, skip the regulator. Costly and in my experience,
unnecessary if your panel power output capability is small compared to
your battery AH. I use a 2 amp panel on 8D diesel starting batteries,
no regulator, zero problems. If you are getting into bigger panels why
pay $70-100 for a regulator? Just use an IC voltage regulator. Sure,
you'll lose some power in heat, but you wont over charge if you keep
the voltage below about 13.8 VDC or so. You can rig these ICs to
control external power transistors if you are dealing with current in
excess of the IC ratings.

Some top end solar panel regulators are very sophisticated and can
actually boost voltage to eek out a tiny charge during a sunset, but
thats not needed in my application.

Mark
SF CA

I thought I mentioned that small arrays of panels couldn't over charge
a bank of batteries :-)

I was asking about the preferred type of regulator, i.e., shunt, open-
close circuit, short circuit.

My own boat has three panels charging a medium size bank and never
gets above 13.5 V. On the other hand it will only run a DC fridge if
the sun shines all day, every day.
Cheers,

Bruce