Fridge quit cooling in the deep cold

[Pete Masterson]

Watts divided by volts = amps so 1000 watts (1 kW)/120 volts = 8.33 amps.

Since that is used over a period of 1 day (24 hours), that's an average of about .35 amps per hour.

Figure in some loss due to the inverter, so about .5 amps per hour is the use at 120 VAC.

Then converting the 120 v amps to 12 v amps, you get an average of about 5 amps per hour from the battery. Actual consumption at a point in time may be higher -- so you also need to check the peak draw. What is the refrigerator's nominal power rating (amps or watts) when it is running? The battery will 'feel' the actual draw, so it may draw down more quickly than it would if the average draw was the actual draw due to the physics of batteries.

Check Consumer's Reports -- the energy calculation on _some_ refrigerators is bogus (you use much more than they claim) but on others it is OK. So, check the energy use as calculated by CR before you commit to buying a particular unit.

Having an all-electric coach with a standard 22 cu ft side-by-side door home-style refrigerator, I can assure you that's it's practical to not have an LP gas refrigerator. I would suggest using a true sine wave inverter (if possible) to get better efficiency from the refrigerator motor. The modified sine wave inverters cause the motor to run hotter, using more electricity (than spec) and probably diminishing the eventual life span of the refrigerator compressor motor.

Pete Masterson

'95 Blue Bird Wanderlodge WBDA 42 (For Sale)

<http://www.aeonix.biz/BBforsale.html>

El Sobrante CA

"aeonix1@mac.com"

On Dec 24, 2008, at 8:27 AM, timvasqz wrote:

Glenn if it is possible to do the trade with minimal effort, I think 

I would revisit the inverter use of a modern green midsize refer to 

replace the amonia setup in my bus.  I was looking at putting a mid 

size compressor style refer/refridge in the area I park our bus to 

transfer refer goods when docked because electric to run the boiler 

on the ammonia system seems high. Our rate for 200% of allotment is 

around $0.35 per kilowatt hour in Romoland. 

the mid size combos have tags that claim they cost only $43 per the 

year to run at$0.16 per kilowatt. The math???? 

4300 / 16 = 269 Kilowatts per year.  269 KW / 365 days = .7363 

Kilowatts per the day to run. 

Does anyone know of  conversion math necessry to calc the battery 

needed to invert 1 kw per the day??GregoryO'Connor ofTim&Greg

94ptCa