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Small Cabin Forum / Off-Grid Living / Refrigerators and inverters
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Atlincabin
Member
# Posted: 29 Jun 2017 01:02
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So, I have been using a Vissani refrigerator at the cabin for the past 4 summers, and running it from my solar/battery system. I have noticed that in the manual it states that this refrigerator is "not for use with inverters" but it has seemed to work fine until.....this past week we were gone for several days, and it quit running (didn't lose much stuff, fortunately). I reset the defrost timer and it came back on fine and has been running fine for a couple days now.

So, a couple of questions:
1) why would a refrigerator be incompatible with an inverter system, since most inverter systems are pretty clean? Perhaps they state this because of the surge power draw when the motor kicks in? Perhaps because of issues with non-sine-wave inverters? Any insights appreciated.

2) why would the refrigerator appear to quit (symptoms of a failed defrost timer) but is really ok? My pet theory right now is that it has something to do with no other loads on the inverter, so the inverter goes into sleep mode and without an external load other than the refrigerator timer, the timer load is insufficient to wake up the inverter, thus the timer gets effectively stalled and never kicks the fridge on. The obvious solution (if this is indeed the problem) would be to leave some small load on all the time to keep the timer running properly.

Thanks for any insights.

Steve_S
Member
# Posted: 29 Jun 2017 07:59
Reply 


I know that Inverter's which are not "Pure Sine" can cause a wide assortment of problems with electronics and some motor types. The inverter also has to be able to handle the full surge on start because if it's borderline, the inverter could be damaged over time which would result on more failures...

It would be helpful if you included the Make & Model of both the Inverter & the Fridge you have, links if you got'em for web docs on the products... You'll get better and hopefully more helpful feedback to your query.

ICC
Member
# Posted: 29 Jun 2017 09:44
Reply 


Modified sine wave inverters make all motors run hot, some may run hotter than others, but they all run hotter. They run hotter than designed and that kills them sooner or later. Was it mod wave?

Atlincabin
Member
# Posted: 29 Jun 2017 09:46
Reply 


Refrigerator: Vissani HMDR1030WE (~10 cu ft) - manual is basically useless with regard to this sort of problem
Defrost timer: Beijing Haitailong DBYC1408BL - may be obsolete as I can find no info on this online but lots of very similar models
Inverter: Magnum MS4024 (4kw, pure sine wave inverter) - more than sufficient to handle the surge power requirements

Steve_S
Member
# Posted: 29 Jun 2017 10:28
Reply 


That's a good inverter and has a good rep (minimal troubles & problems reported) and Pure Sine should have no issues. It can certainly handle the surge from the small fridge as it's rated for 5000 watt momentary surge from what I can find.

I did see some writing on the CGFI outlets on some models could be a problem and cause some failures in attached equipment but somehow I don't think that applies to your model.

Not kidding about poor info on that fridge... Geez that's pretty sad, lack of info that is... And this is a product sold by Sears as well, so it's not a fly by night company made by garden gnomes. That "do not use with inverters" line does pop up though, so they seem to have a known issue but I could not find a detailed discussion on what the particular issue is.

Atlincabin
Member
# Posted: 29 Jun 2017 12:43
Reply 


Steve, I suspect the "do not use with inverters" line is there to warn folks who might be using square wave or modified sine wave inverters, but don't know for certain. It has been pretty trouble-free for the past 4 summers, running full-time. It just happened to shut down while we were gone for several days, otherwise I probably would have noticed the problem earlier. I'm still suspecting the timer somehow is the problem, although it has been doing ok since we returned from our trip. Just a bit of a head-scratcher.

creeky
Member
# Posted: 29 Jun 2017 14:09
Reply 


The defrost timer is one reason you can't run fridges on MSW. Why you'd have trouble with a pure sine. Doesn't make sense.

The inverters I've been testing are actually smoother than the grid. Well. Go figure.

Hopefully it was a anomaly never to be repeated. Or its the timer itself that's at fault.

Willie1959
Member
# Posted: 29 Jun 2017 16:01
Reply 


Have been running fridges off of inverters for 17 years no problems . Current inverter is a 2500 watt outback 24 volt . Have 2400 watts solar and 600 amphr battery bank, to it running when I am not there. I use an old pallet truck battery charger to recharge battery bank when needed. Its used on auto start for the generator 4500 watt onan . It rarely starts as I check the hour meter.

Willie1959
Member
# Posted: 29 Jun 2017 16:01 - Edited by: Willie1959
Reply 


Have been running fridges off of inverters for 17 years no problems . Current inverter is a 2500 watt outback 24 volt . Have 2400 watts solar and 600 amphr battery bank, to it running when I am not there. I use an old pallet truck battery charger to recharge battery bank when needed. Its used on auto start for the generator 4500 watt onan . It rarely starts as I check the hour meter.

Cowracer
Member
# Posted: 29 Jun 2017 16:03
Reply 


Not for nothing, but many new campers have the option of a full-size residential fridge. With those, you loose the ability to run on propane while travelling, so they set them up to run on inverters off the house batteries.

And if I know my camper manufacturers, they use the cheapest inverter you can get.

Tim

Willie1959
Member
# Posted: 29 Jun 2017 16:23
Reply 


http://www.ebay.ca/itm/AC-110V-220V-Digital-100A-watt-power-meter-volt-amp-Ammeter-Vo ltmeter-80-260V-/221755573148?hash=item33a1a9839c

Get this for your system typical fridge uses 1.2 KW per day defrost cycle not included.

Atlincabin
Member
# Posted: 1 Jul 2017 09:38
Reply 


Thanks all for the comments. Seems that the culprit is likely the timer about to fail, so I think I'll have a spare on hand to replace it if/when necessary.

CabinBuilder
Admin
# Posted: 1 Jul 2017 12:31
Reply 


Consider 12V refrigerators, like ones for RVs and boats.

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