[RE-wrenches]

[sunwise]

Greetings Nick,

I was interested in your take on the Modified Square Wave vs. SW
inverter and differences in their ability to provide robust charge
rates.  I have always felt that it was the lack of peak voltage from the
gen-set that limited the charge current, not squarish/v/sine at the
inverter end.  Unless it is a switching type inverter/charger, the
device is using a transformer as the primary means to change voltage.
To use a 12 volt inverter as an example, there is essentially a 10 to 1
winding in the transformer.  You put 12 volts in, you get 120 out.  On
the charger end, you put 120 in and you get 12 volts out.  Based on
this, if all you put in was 120 volts, you couldn't charge the battery
above 12 volts, and as battery voltage approached 12VDC charge current
would fall off.  Peak power is where the real ability to charge comes
from and cheaper or smaller gen-sets don't deliver.  I have always
thought this was true of modified square wave as well as sine, if they
are both transformer based.

I have also heard about "developing" the plates, although I always
wondered if this wasn't just battery manufacturer gibberish when a new
battery doesn't seem to be living up to its stated capacity.  

In any case, I still like to use Mods in some system designs, and when
properly matched to a gen-set they can provide decent charge current.

Kurt Nelson
SOLutions

-----Original Message-----
From: paul wilkins [mailto:inkings at swcp.com] 
Sent: Tuesday, September 17, 2002 1:51 AM
To: RE-wrenches at topica.com
Subject: Re: [RE-wrenches]

John, I think Nicks right. Paul Wilkins

Nick Houser wrote:
> 
> John----My guess is that you will see an increase in charge current
after a
> few cycles and the batteries are broken in properly.  I have been told
by
> battery manufacturers that the smooth surface of the positive plates
in the
> new cells limits the charge capability. AS the cells "break in", the
surface
> of the plates gets "etched" effectively increasing the affective
surface
> area and allowing a higher charge rate. If the inverter was a square
wave
> unit, you might suspect that the problem was the generator output wave
form
> limiting the charge capability, and loading the generator  might help,
but
> with the SW, I suspect the brand-new batteries are the culprits. My
two
> cents worth.  Nick Houser   Off Grid Power.
> 
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