Norcold fridge and DC power....

Lindy

Hello, we have a Norcold NR740BB AC/DC fridge in our 2014 T@B Max CSS. We installed 2 Trojan T105 6v batteries in series, instead of the default 12v deep cycle. Recently we have noticed the fridge has been cycling endlessly without cooling after about 2-3 days of dry camping with occasional 1-2 hour a day generator runs through the shoreline plug. When the endless cycling starts, the current charge on the batteries is around 12.0-12.06 on a voltmeter 12v plugin through the galley. I do see in the manual that the fridge has a cut in
has a Restart (cut -in) min. voltage req. of 12.2. I can only assume this is why it endlessly cycles, because it is below that req. voltage. The problem is I don't remember this being an issue last year when we used it. When the batteries come off a couple days charging via the shoreline my voltage on that same plug in meter reads 12.68, after unplugging,and 13.23 while the shoreline is powered. Any thoughts or ideas? The local RV place told me that with the draw that fridge has that 2-3 days is about all I should get with those batteries.

Thank you in advance.

Ratkity

Do you just have the 2-way Norcold so you don't have the propane option? I know the 2-way is more efficient on battery power, but it's still an energy hog. What else are you running inside? Have you checked the water level in your batteries lately?

irvingj

The Norcold 740 is an AC/DC only (no propane) unit. Amp draw @ 12VDC is 3.6, according to their literature. Doubt it would go for more than a couple of days on batteries without back-up. Lindy, your battery voltage sounds good both during & after charge, but have you had their amp-hour capacity checked?

jkjenn

3.6ah (assuming constant use, over 24 hours is 86.4ah. If you add in parasite draw, you are looking at over 91ah in a 24 hour period. Your battery capacity is 225ah. You will have used almost half of your battery capacity within 24 hours if you use nothing but the fridge and the parasitic drain. In other words, unless you are recharging, somehow (solar, generator, or shore power), you will get one day's use of batteries with constant fridge use.

You could turn it off for a few hours at a time to extend this, but solar seems like a good solution.

jcfaber1

We have a 2007 DM t@b with the 2 way fridge.  My experience is that it runs 20-25% of the day.  At that rate you would use 22 AH a day.  If you are fully charged, does it still cycle frequently on and off?  How about on AC?  It would work fine on AC. Ours would cycle frequently with out cooling and I replaced the convertor.  Problem solved.
John