Forum Discussion

imgoin4it's avatar
imgoin4it
Explorer
Sep 05, 2019

Residential refrigerators

Installing a residential refer in my coach replacing the non working Norcold. I believe new RV’s with residential refrigerators are operating with pure sine wave inverters. My existing inverter is a modified sine wave. It works fine on the existing, but can I expect longer range problems with the old inverter, or should I “bite the bullet” and spring for a pure sine wave inverter ?
  • I am not an electronics guy but suspect there is a difference between cheap msw and pricier msw inverters.

    A long time ago I was being wooed my the Thou Shalt buy a PSW inverter or the world will end crowd. The old guys rolled their eyes and did not say much.

    I put in a Trace 3624 and used it for 10 years with Flat Screen TV, satellite dish, charging cell phone batteries, power tool batterys, computer, printer, house hold refrigerator, microwave, on and on. The only problem I had was the clock on the microwave would go berserk, but the micro wave functioned just fine.

    So me personally I would not run out and buy a new inverter. PSW is way cheaper now than it was, so I might buy one at replacement time.
  • My GE 22 CF side-by-side ice/water through door, auto defrost, auto ice maker, etc. has run perfectly on a MSW inverter since 1999.
  • I’m thinking I am ok with the modified inverter. Have a 2000 watt inverter, four good house batteries that charge on shore power or the engine and operating the refer over last 3 or 4 days it works great. Refer is an 18 cf counter top depth by GE. GE engineering section says they do not test their refers on any inverter, “ however having said that” recommend pure sign rather than modified. Knowing the difference, I think that is the only answer they can or will give. Am aware of the advantages of pure sine over modified,starting load etc, etc, got it all covered. Just do not know how refer might perform over the long run. Knocking at 80 years old not even sure what the long run is, but I’m still RVing and plan to keep on .
  • imgoin4it wrote:
    It works fine on the existing, but can I expect longer range problems with the old inverter, or should I “bite the bullet” and spring for a pure sine wave inverter ?

    Electric motors (including the compressor inside your refrigerator) run more efficiently and cooler on a PSW inverter.
  • I've been running my residential frig on my MSW inverter since 2015.
  • Depends on the brand of fridge. Some are fine with MSW and others are not. Some manufactures will tell you what their units require
    Typically, 120VAC motors run cooler and last longer on PSW.
  • The res fridge 120v does not need to be from a PSW inverter. BTDT. MSW works just fine with that. What counts is that the inverter, whichever type, has the surge allowance for the fridge.

    From posts on this topic in this forum, it seems you will need about a "1000w " inverter, properly wired with fat gauges and a decent set of batteries for it. Not to speak of a way to recharge the batteries off-grid!