120 VAC/LP absorption to 12 VDC compressor

[Want a B]

Dometic RM3762 refrigerator converted from 120 VAC/LP absorption to 12 VDC compressor. Conversion done by JC Refrigeration, Shipshewana, Indiana.

Battery: Two lead acid. Deka Marine Grade. 575 CC each.

Electrical monitoring: Victron BMV-712. Victron programed for 575 amps.

Test. Batteries were 100% charged. Compressor refrigerator was ran for 25 hours. No other electrical load. Victron indicated batteries could power the converted refrigerator for 10 days (50% capacity).

Am I understanding this correctly?

P.S. I have no financial interest, family or friends working for nor received any compensation from Dometic, JC Refrigeration, Deka or Victron.

[GeorgeRa]

Originally Posted by Want a B

Dometic RM3762 refrigerator converted from 120 VAC/LP absorption to 12 VDC compressor. Conversion done by JC Refrigeration, Shipshewana, Indiana.

Battery: Two lead acid. Deka Marine Grade. 575 CC each.

Electrical monitoring: Victron BMV-712. Victron programed for 575 amps.

Test. Batteries were 100% charged. Compressor refrigerator was ran for 25 hours. No other electrical load. Victron indicated batteries could power the converted refrigerator for 10 days (50% capacity).

Am I understanding this correctly?

P.S. I have no financial interest, family or friends working for nor received any compensation from Dometic, JC Refrigeration, Deka or Victron.

Your post is a prime example that numbers must have correct units otherwise it is gibberish. You are mixing CC with amps. I think you meant Amphours in lieu of CC and Amphours in lieu of amps.

If you used 50% of 575 Amphours [Ah] your fridge consumed about 30 Ah per day, seems feasible.

[booster]

On edit



If it is this one,


https://labatteries.com/product/00/d...CCA175-Res-Cap


It is only 90 amp hours each so used 42% of your capacity of 180 AH. You would get about 2 days of run time if you took them to 80% discharged and didn't use any other power.

We are back to the old mix up between amps and amp hours. CC is cold cranking amps, not amp hours which is what you program into the monitor. If they are really marine grade batteries, you should be able to get the 20 hour rated amp hour rating, and that is what you would put in the Victron.


You probably are looking at somewhere in the 200-220 amp hours of capacity. Do you have the model number of the batteries?


If the consumed amp hours shown on the display is correct for 25 hours, you used a lot quite a lot of power at 76 amp hours, unless it was started warm. You would use about 35% of the capacity of the batteries if they are really only 220ah which is typical in class b's.

[booster]

Originally Posted by GeorgeRa

Your post is a prime example that numbers must have correct units otherwise it is gibberish. You are mixing CC with amps. I think you meant Amphours in lieu of CC and Amphours in lieu of amps.

If you used 50% of 575 Amphours [Ah] your fridge consumed about 30 Ah per day, seems feasible.

I wonder about the 1.14 amps in the display as that is very low for any compressor frig if it is using a Danfoss compressor, and this appears to be a 7.0cf frig.

[Want a B]

Originally Posted by booster

.... Do you have the model number of the batteries?...

Model DC27

[Want a B]

Originally Posted by GeorgeRa

... You are mixing CC with amps. ....

You are 100% correct, 80 AH per battery for a total AH of 160. Victron has been reprogrammed accordingly.

[mkguitar]

what is the current draw ( amps) when the fridge is running please


( I want to understand that part of the equation)



Mike

[Want a B]

Originally Posted by mkguitar

what is the current draw ( amps) when the fridge is running please


( I want to understand that part of the equation)



Mike

Victron screen capture attached to OP. 1.14 amps

[booster]

Originally Posted by Want a B

Victron screen capture attached to OP. 1.14 amps

Was there any solar running or other charge source going on? I doesn't seem right as it is so low and it also doesn't add up to the 76ah used on the monitor.

[GeorgeRa]

Originally Posted by booster

Was there any solar running or other charge source going on? I doesn't seem right as it is so low and it also doesn't add up to the 76ah used on the monitor.

Indeed, 25 hrs * 1.14 A = 30 Ah.

[GeorgeRa]

Originally Posted by Want a B

Victron screen capture attached to OP. 1.14 amps

Going back to the original question, did screen capture current while the fridge was running?

[Want a B]

Originally Posted by GeorgeRa

Going back to the original question, did screen capture current while the fridge was running?

I thought it was.

No solar.

No other energy use.

[themexicandoctor]

My 2 cents.

I recently converted to a Novakool DC Fridge, JC Refrigeration do not offer a conversion for smaller 3 way units.

As it is, my unit when cyclying pulls no more than 2.2amps.

Here are 2 snapshots of my Novakool when it is;

#1 Cycling ie; compressor is running to cool the unit

#2 Not Cycling.

Please note that any other draw you are seeing may be an accessory fan in the rear lounge, the Fantastic Fan, LED Lighting, etc or a combination thereof.

[themexicandoctor]

By golly, I hope I got those terms correct this time ...

[themexicandoctor]

I now have 2 x Lifeline 6 volt 225ah batteries.

Does this mean that I do NOT NEED change my Amp Hour Capacity on my Victron BMV712 because;

2 x 225ah = 550ah (6 volt) which means

I divide that figure by 50% to convert it to 12 volts = 225ah

Which means my system should be configured for 50% of 225ah for a calibration of 112ah total capacity?

Or leave it?

[Jim86301]

Am I correct in thinking that the 2 x Lifeline 6 volt 225ah batteries would be connected in series to get 12 volts. With a series connection voltages are added up, amp-hours are not so you have 12 volts at 225ah.

[booster]

Originally Posted by Jim86301

Am I correct in thinking that the 2 x Lifeline 6 volt 225ah batteries would be connected in series to get 12 volts. With a series connection voltages are added up, amp-hours are not so you have 12 volts at 225ah.

You are correct.