Norcold 30 on batteries

DCN082162

We are planning a trip soon with our T@G so I wanted to test systems out before we leave. Particularly how long the fridge will run on batteries alone. Our T@G has 2 12V Deka Marine batteries wired in parallel I think they are group 24 size Jan 2019 date code. The Amp Hours (20 Hr Rate) is 105. My Norcold draws about 4.3 amps@12V per specs. I disconnected the T@G from shore power the batteries showed 13.8V and the fridge was running set at 32, after about 24 hours the fridge would not keep temp and my batteries were down to 12.4V. I would have thought that with 2 batteries it would have been about 48hrs runtime, as 105X2/4.3=48.8
So are my batteries in need of replacement? is my math wrong?

beaky

Norcolds not the most efficient 12v fridge, put beer or pop cans in the bottom and run it at 38 degrees. if you don't have solar panels you will not go long off grid

SueBHunny

@beaky said:
Norcolds not the most efficient 12v fridge, put beer or pop cans in the bottom and run it at 38 degrees. if you don't have solar panels you will not go long off grid

But WITH solar it's a godsend! 100 Watts of solar keeps mine running great!

beaky

yup, solar is all you need to cool the beer forever

JamesDow

When I had one deep cycle battery, I could squeeze a weekend with the norcold running. I would hope you would get more than 24 hours from your batteries. A lot of factors at play. Depending on how the batteries have been charged and discharged over the last two and a half years would make a great difference as to the life span of the batteries.
I would look at replacing them with two matched batteries. Make sure you get true deep cycle batteries. A lot of marine batteries such as the Deka DP31DT is a deep cycle/starting battery. They work fine, but may not be optimized for your trailer needs. They are at the right price point.

How long is your planned trip? As for your calculations, the draw of the Norcold would not be a constant 4.3 amps (the compressor is not always running).

WilliamA

2 each 105 AH batteries = 210 amps. Assume 50% load capacity = 105 AH available. Divide by 3 amps (that's the 24 hour average I use for the Norcold) and you get 35 hours "assuming there's nothing else running". Turn on some lights, a fan, radio...charge a phone and laptop etc and that brings you to about 24 hours run time on your 2 batteries. Sounds about right to me. Remember: As the batteries lose voltage, amperage needed goes UP.

WilliamA

WilliamA

I tested my Norcold once, running straight off the battery with nothing else hooked up to the battery, Norcold set to 40 degrees with outside temp at @75°. Battery tapped out (Norcold quit at battery threshold. 10.5V) at about 13 hours.

WilliamA

DCN082162

Thanks for the input guys. I do have a 100 watt solar panel on the trailer so that will come into play. But I wanted to test worst case. I did get lazy and only checked the date code on one battery. So a mismatch situation is a possibility.
The planned trip is about 8 days, we have a 2200 watt generator that can be used as well. But we will be in State Parks for a few days and the gennie can't be run during quiet hours, but we usually don't need it. We are testing out a new old Tow Vehicle on this trip so I am trying to eliminate variables. The new old TV is 2004 Grand Cherokee Overland, that I recently had an engine put in. It does have several thousand miles on the new engine so its broken in OK.
William why 50% load capacity?

JamesDow

A typical lead acid battery, as you have should only be discharged up to fifty percent before damage to the battery occurs.

ClarkGriswold

Did you test with the Norcold full or empty? It makes a HUGE difference in energy consumption. With my ARB and my Norcold I always bring water bottles or other beverages in a separate cooler (hard or soft bag with an ice pack) to replenish the space in the fridge to keep it full. My installed solar is almost always able to keep up with demand and recharge the rolling day.

Sharon_is_SAM

@DCN082162 - just want to make sure you precooled on shorepower. And, ClarkGriswold has a good point about keeping the chest frig cool. We have an ARB and keeping a full frig and a frozen quart bottle of water helps to maintain the temperature and reduces cycling and battery use.

DCN082162

The cooler was not precooled, and had several water bottles. In normal use we do precool the unit with frozen water bottles.
James I get your point about charge capacity vs voltage I had forgotten to account for that.

beaky

we have gone out for weeks in Az and Utah in August with a 100w flex panel on the roof and run the Norcold at 38 with no problems off the Centennial deep cycle. Precool and keep cans of cold Tecate in it and you will do well

GigHarborTom

All we had is a new 12 Marine RV battery. Survived three days and nights. Cooled the Reefer before takeoff. One frozen gallon of water in the bottom at takeoff. Set reefer at 35 ( I think). Used CPAP at night, minimized light usage, Hatch open all day. No TV, No Ac ran well entire time. Recharged the battery at home with charger twice. Followed by same usage. Twice ran fine for three days and nights. Testing to see how long I can get way with this before I might upgrade. While these trials were boondocking, we usually set up with power and water available. Just find it painful to spend big bucks to upgrade. Made that expensive adventure restoring 3 vintage trailers. Upgrading to more than we really needed for our usage. But it was fun.

Somemedic

Dont run 2 12v in parallel.

Get 2 6v golf cart bats in series. Theyre longer lasting.

Then get solar. Like a 200+ watt flexible panel and renogy controller.

You'll never have to plug in again unless ypu want AC.

mgreen2

We can use the Norcold indefinitely with 100 watt Renogy Solar suitcase if we set it as a refrigerator. If we know we will have shore power we use it as a freezer and bring an ice chest for drinks and fresh food. We use 4 ice packs in the ice chest and keep 2 in the freezer to rotate 2 each day.