Re: (ET) Solar charging, part 2

["harry landis" <hlandis hotmail com>]

I think my controller would work fine with a DC solid state relay instead of 
the AC one. As it happens, I have some DC SSRs available. So if anyone wants 
a controller with a DC SSR (30 amps, I think) just ask. Same price ($40 
including shipping). Note: this control scheme won't work on a normal solar 
installation. It only works in applications like the ET where there is 
essentially no power drain on the batteries while charging. If there is 
significant current being taken from the batteries, the battery voltage is 
no longer the rest voltage, but is lower due to the drain. So the controller 
thinks the battery is always low, and ends up overcharging it.

Harry Landis





From: Jeremy Gagliardi com
To: elec-trak cosmos phy tufts edu
Subject: Re: (ET) Solar charging, part 2
Date: Tue, 22 Apr 2003 16:04:28 -0400 (EDT)

On Tue, 22 Apr 2003 16:00:07 -0400, "SteveS" wrote:
> Yes, at the relatively low currents that we are talking about (5A or so),
> there are inexpensive controllers one could make or buy. Now, where do we
> buy cheap (err, inexpensive) solar panels?
> SteveS
> E12Ss
> E20

Okay, now the next question is who can build one (Harry Landis, are you up 
to
the task)?  I haven't dabbled in electronics since I took a required course 
in
college for my CompSci degree.  That was 11 years ago, and I don't remember 
a
lick of it.  Although, if someone drew up a schematic, I might be able to 
follow
it.

--
Jeremy
E20

> > This makes me wonder if it would be simpler to build a simple DC
> controller,
> > similar to the Landis model.  The Landis Controller is a solid state AC
> relay
> > with a simple DC monitor (when batteries go below 38V it turns on the 
AC
> relay
> > to the charger).  Can't a similar controller be built that monitors the
> > batteries in the same exact way, but opens up a DC relay from the solar
> panels?
> > The Landis Controller is only about $40.



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