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solarcalc_fyi
Member
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# Posted: 4 Oct 2026 08:07am
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For cabins that keep a compressor fridge running between visits, have you measured the electricity used during an unoccupied day, separately from a normal occupied day? I am interested in the always-on loads that are easy to miss: inverter overhead, networking, controllers and the fridge itself.
One useful comparison would be a full 24-hour fridge reading at its AC plug versus the same period's total energy drawn from the battery. The difference is not automatically all inverter loss: other loads may be included, and a battery monitor that reports net charge/discharge can hide daytime consumption while solar is charging. The measurement boundary matters.
For a hypothetical example, an inverter drawing 20 W continuously with no load would use 0.48 kWh in 24 hours. That is only an illustration, not a specification for any product. It should not be added again if the battery-side measurement already includes it, nor assumed to remain an extra constant 20 W under every load. Search/standby modes may behave differently and may not work with every fridge.
If you have compared occupied and unoccupied days, what stayed powered, where was the energy measured, and what was the approximate cabin temperature? Did the difference change how you planned winter visits or cloudy-day reserves? No need to change wiring or switch off equipment that needs to stay on just to collect a reading.
Disclosure: I maintain a solar-planning website. I do not have my own cabin measurements to claim here; I am interested in understanding real operating conditions. This is not a product recommendation, and there are no sales links.
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Brettny
Member
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# Posted: 5 Oct 2026 06:04am - Edited by: Brettny
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When i leave the inverter goes off and the DC USB plugs get turned off. This just leaves the charge controler on. Everything i go there the batteries are full. I see no reason to kill a battery or risk a fire just to have a cold fridge.
We have a wood stove and have arrived to a 15*f cabin. In about 2-3hrs the place was up to 70*. In October we winterize all water and use a jug under the sink and foot pump for winter water. Takes aboit 30sec to winterize when we leave. I have many military water jugs that have survived being frozen solid all winter.
I almost forgot about solar conditions in the lake effect snow area of NY. There it can be sunny and snow all in 5min time. This means even near vertical pannels get a layer of ice on them the next wave of sun can't melt. Theres many weeks we dont see a bluebird sky or even the sun...until the lake freezes. Also when your cabin is 15f many inverters have a low temp shutdown at 32f. There are only a few inverter companies that have a low operating temp. Victron and xantrax are two.
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FishHog
Member
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# Posted: 5 Oct 2026 07:16am
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Absolutely everything is powered off when we leave
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gcrank1
Moderator
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# Posted: 5 Oct 2026 12:20pm
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For me the overhead of leaving anything hooked up has bit me 2x so now all on output side is disconnected from bat bank.
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Atlincabin
Member
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# Posted: 5 Oct 2026 02:24pm
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Really depends on a lot of variables, as you noted. I will leave my system running if gone for a few days at a time, but shut down over long absences. Although I have not specifically measured fridge use vs. inverter+fridge use, I suspect that there is not much difference between real world and the reported usages for the fridge and for the inverter idle. One thing I will note is that my experience has been that for my fridge, if it is the only thing running over maybe 24 hours, that sometimes the inverter (Magnum) doesn't get triggered to come on when the fridge tries to start. Not sure why that has happened, but I have learned to leave something else minor running (like a night light) continuously so that the inverter will come up when the fridge kicks in.
Hope that gives you some useful info.
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paulz
Member
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# Posted: 5 Oct 2026 03:52pm
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SCC, hopefully making power, and trail cam
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philpom
Member
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# Posted: 5 Oct 2026 07:01pm
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We unplug everything, turn it all off except the fridge and outdoor motion lighting. Costs us around 3$ a month. We do have grid power we had run in a number of years ago. We like to leave certain basics up there and put everything in the fridge like pancake mix, coffee, condiments, etc to keep it fresh.
Well worth it.
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solarcalc_fyi
Member
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# Posted: 5 Oct 2026 09:07pm
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Atlincabin, your distinction between a few days away and a long absence is useful. Those are separate operating cases. The missed restart matters too: saving idle energy only helps if the inverter reliably wakes for the appliance. What are the exact Magnum inverter and fridge models, and was search/standby mode enabled? I would check their manuals before treating an added night light as a general solution; it adds a continuous load and the cause may be model-specific. No need to repeat a test that could leave stored food without cooling. For future energy readings, noting continuous-on versus search mode would help interpret the result. Thanks for identifying this constraint.
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gcrank1
Moderator
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# Posted: 5 Oct 2026 10:29pm
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Why not cut the chat and give us the link
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solarcalc_fyi
Member
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# Posted: 6 Oct 2026 09:03am
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gcrank1, fair point. The site I maintain is https://solarcalc.fyi/ and the fridge-specific page is https://solarcalc.fyi/solar-calculator/refrigerator . The calculator is free and does not require an email address. Some equipment pages contain Amazon affiliate links; I may earn a commission from qualifying purchases. The estimates are planning aids, not a substitute for measured consumption or a checked installation design. Thanks for asking directly.
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gcrank1
Moderator
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# Posted: 6 Oct 2026 10:14am
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Ah, now we know......
That will do, we dont need any more info
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Atlincabin
Member
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# Posted: 10 Oct 2026 05:38pm
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Inverter is a Magnum MS4024 (4kW, 24V). Refrigerator is a Vissani 10 c.f. model, top freezer.
This was a number of years ago, so I do not recall whether the search mode was on - probably was on, but I cannot say for absolute certain. I believe that the inverter will stay on as long as there is a small draw of a few watts, but I don't recall the exact threshold. I now have enough stuff that runs enough of the time (and sufficient panels to accommodate that) that such a shutdown is not a problem.
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Brettny
Member
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# Posted: 11 Oct 2026 08:58am
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My inverter was in power save mode also and I found that a fridge didn't run enough or wasn't enough load for it to work right.
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