Inverter for home + recording studio [RE-wrenches]

[James Lamb, Middle Fork Engineering]

I found the power star to be a good inverter. A friend of mine is using it
on a 10 amp 12 volt hydroelectric plant. It runs the TV computer and stereo
fine with little interference.

One thing I did notice was when I was running an AC Refrigerator load using
my weak Nicads, the inverter would turn off when batteries were at 10.5
volts, then turn on when the batteries were at 12 volts (The inverter is
specified to should turn on at 13 Volts which it would not). This on and off
cycle would occur a few times per second. What was happening, the nicads
were recovering from the solar input rather quickly and when the inverter
turned on in a short time the refrigerator compressor would lock ( electric
motor would not turn because of the pressure of the refrigerant in the
compressor cylinder) increasing the load on the inverter causing the voltage
of the batteries to go below 10.5 volts shutting down the inverter. The
voltage would recover to 12 volts in less than a second turning the inverter
on then it would shut down in a fraction of a second. The self setting
overload circuit breaker in the refrigerator compressor would not get hot
enough to shut down the compressor. Not a good situation since I don't know
what would happen long term. I had Powerstar modify the on off voltage set
points with a wide range of 11 volts to 14.5 volts. This solved the on off
problem. The system has since been upgraded and the Powerstar has found good
use for AC loads in a small hydro plant installation where the refrigerator
is operated on 12 V DC.  

Has anybody ever ran into this situation with the Powerstar or other
inverters ? 
It was an unexpected learning experience of long ago and we should all be
aware of it since in can happen when battery capacity gets low due to age
and use.	
To bad Powerstar has not further developed their inverter with options.

Jim Lamb	
Middlefork Engineering 
Northbrook, IL. 60062
middleforke at yahoo.com

     

> ----------
> From: 	John Blittersdorf, Cent. VT Solar &
> Wind[SMTP:cvsolar at aol.com]
> Reply To: 	RE-wrenches at topica.com
> Sent: 	Friday, September 01, 2000 4:23 AM
> To: 	RE-wrenches at topica.com
> Subject: 	Re: Inverter for home + recording studio [RE-wrenches]
> 
> Kurt,
>    I used a PowerStar 1300 watt in my home for several years and didn.t 
> notice a problem with my stereo.  However I sold it to someone with a
> small 
> 12v cabin system and while working there later noticed it affected their
> FM 
> Radio boom box.  I'm not sure what the difference was except for being in
> a 
> different building.  I wired both homes and had similar grounding etc.
> There 
> is a very long inverter feed line from the batteries though. (about 12' of
> 
> 2/0 THHN)  it may be the radiating antenna.
> 
> John
> CVSolar
> 
> 

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