refrigerator start surge

 

My old 3000 watt Vector inverter finally died so I replaced it with a
new 3000 watt Vector. The new one works well but is has a hard time
starting my tiny 3.7 CF Sanyo refrigerator. When the battery bank is
above 13.5 volts, the inverter shuts down when the refrigerator
compressor kicks on. This happens even when there is nothing else
plugged into the inverter.

The refer works fine on my 400 watt, and my 1000 watt inverters.
The old 3000 watt Vector (different model) ran the refer just fine.
The Vector runs the washer and other large loads just fine.
The vector starts and runs the refer if the voltage is below 13.5.

Any ideas why this might be happening?

Q

 



     Look at your supply cables.  Even a fraction of an ohm of cable resistance
and/or contact resistance could be sufficient to make the voltage on the input
terminals of the big inverter momentarily drop below the point where it
automatically shuts down.   Does it shut down with any other loads?

Vaughn

 

Vaughn,

The cables are huge welding cables, under 3' long, and terminals are
clean. The inverter runs the washing machine and other big loads just
fine. The washer is at least 10 times the start surge of the little
refrigerator.

Q

Vaughn Simon wrote:


resistance

 



Just a wild guess, but I'd say the new inverter has a protective
current limiting cutout that also looks at the voltage.  The float
charge on a pure lead battery is 13.5 volts, and lead - antimony, and
lead calcium are less than that.  I know you can get a surface charge
higher than 13.5 vts, but in general, a voltage above 13.5 vts means
you are charging in some fashion, or have just recently charged.

I think it is Black and Decker that bought out Vector.  You might try
contacting them and seeing if the cutout point can be adjusted.

 



I had a problem with voltage loss on a 12 volt DC system on starting
something.

I used a big capacitor to get over it, so if you have a big capacitor of
sufficient voltage kicking around somewhere, then you might try it, from
memory I used something like a 30 volt DC capacitor and 1/2 a farad straight
across the battery.

Mind you my problem was in a car, so I had the genny voltage to help boost
it a bit.

I had a voltage booster to run a video camera and equipment, and it had
problems starting when the car was at idle, and so the capacitor helped
boosted the input voltage during this startup to get over this problem, not
sure if it would work in your case, but as I said if you have a big cap
lying around, you could try it, as your problem seems to be when you try and
start the compressor, and the battery voltage drops.