Long Term Refrigerator Use

[Harrysea]

I haven’t had my Marlin for long and I don’t regularly use the DC refrigerator, but we’ll be making a coastal trip soon and will be living dockside for several days and want to keep the fridge running constantly. I assume that it’s fine to keep the fridge running off batteries while hooked up to shore power with the battery charger operating. Does that sound about right?

 

[wspitler]

Most of the newer refrigerators are AC and DC capable and they use AC if both are available. My 2007 330 has one and there is a switch/breaker on the AC panel and I run the refrigerator off AC power when it is available. Are you sure yours is DC only? DC power should be fine if you have a good battery charger that runs off shore power to keep the batteries up in port.

 

[Fishtales]

I think they are DC only. But if connected to an AC source, the battery charger will work fine. I keep mine on at the dock all the time.

 

[Legend]

I had to replace mine last year. The new Isotherms automatically connect to AC if there is power is present and converts to DC after 30 seconds when power shifts to DC. AS stated if you are on shore power the battery charger will keep the batteries charged so you can run the refrigerator without draining them.

 

[family affair]

So how long can you run the fridge only running from the batteries? I know it is a loaded question. I have 2 group 27 batteries on the circuit that feeds the fridge. My concern is battery damage from discharging too far resulting in frequent battery replacement. I'm trying to get a ballpark idea. Is it 2 hours, 8, 12, etc?
A lithium (non-ion) based battery that can handle starting and charging from the engine would be amazing.

 

[seasick]

Some better models of fridges when on DC, monitor the battery voltage and if it goes below a set voltage, shuts off. So your beers might get warm but your battery won't get totally discharged.

 

[family affair]

Some better models of fridges when on DC, monitor the battery voltage and if it goes below a set voltage, shuts off. So your beers might get warm but your battery won't get totally discharged.

I'll have to check details on my model to see if that is the case.
I know most newer Mercs use alternators to charge batteries and I have read that high current draw causes them to die relatively quickly compared to the life of the engine. I know Yamaha doesn't use alternators. Will the charging system on an f150 handle charging these batteries without issue?

 

[wspitler]

At Anchor, I run my refrigerator all night on a bank of two group 31 dual purpose batteries and can still start the engines the next morning. Could run the generator but wife likes it quieter. It may vary a bit depending on ambient temperature, but the specs on the refrigerator can provide the amperage draw. Your F150 Yamaha can handle those batteries with no problem.

 

[Hookup1]

I run mine constantly for months without a problem on both AC and battery power. I recently converted my DC only refrigerator to AC/DC. Easy cheap conversion.

Converting refrigerator from dc to ac/dc

How difficult is it to convert refrigerator from 12vdc to 110vac/12vdc. I have a 2007 marlin I run the refrigerator all summer. While at the dock I am plugged in and would rather not have battery charger on 24/7

www.greatgrady.com

The Yamaha alternator produces plenty of charging current at low rpm’s to keep batteries charged.

 

[wahoo33417]

Harrysea: I don't know the year and model of your battery charger or the style of batteries you run. So I'll just add that it may be worth checking that your battery charger puts out the voltage that your style (lead acid, AGM, etc.) batteries require.

When I recently went with all AGM batteries, I stopped using the 14-year-old charger, not that I had much occasion to use it anyway. A new charger is on the list of things to do, but the old one, and all the wiring, is so dang hard to get to, it keeps slipping down the list.

 

[seasick]

I think that the OP's concern was not so much about whether the motor can charge the batteries but rather can the motor provide more current than the fridge will draw. The answer is of course it can. Most of the smaller to medium marine fridges draw 3 amps or less as an average. Many models draw a lot less on average.

 

[DennisG01]

Harry, just like a fridge at home, it can run year round if you so choose.

Family, fridges (the dorm sized ones) actually draw very little power once "down" to temp. The more food you keep in it, the less power it draws, too, since whenever you open it (try to limit that), you lose the cold air. With more cold food in there, it doesn't have to work as hard.

You should really have deep cycle batteries, or at least dual purpose for this use (extended use with no charging). However, I once ran the fridge (this was on my Sea Ray) for 3 days and nights (one, group 27 DC) and only ran the engine for about an hour or so the whole time. I also had some stereo use, lights at night and Vacuflush use. On the last day, I was able to start the V8 stern drive just fine. I used only that particular battery just as a "test".

 

[magicalbill]

Redundancy here, but I have a DC/only fridge on my 2018 Marlin.

I have run it (the fridge) on long trips, Pt Charlotte FL to the Keys... 180-odd miles and the batteries were never compromised. I have F350's.

Dockside with access to 30-amp shorepower, I run the battery charger all the time. It allows me to use whatever A/C and D/C options I want and the batteries remained charged.

At anchor, I run my Fischer-Panda diesel generator without exception. Reasons are it's best to use the generators as often as is practical and I can run the battery charger and keep the batts charged while we run whatever we want below. (Obviously, we practice Load Management and don't turn everything on at once, but I like to load the generator up more than with shorepower, as it works best under load.)

I've maintained the practices I've outlined above for the 3 years I've owned the boat and it's worked perfectly.

 

[Harrysea]

Thanks for all the advice. between shore power and the Panda, I don’t think there will be any problem keeping the drinks cold and the batteries charged.

 

[Legend]

When running I have never been concerned about the the frig draining the batteries, however if I am fishing and running live wells and wash down with engines off I will just shut off frig with on off knob just to be safe. The frig stay cold for quite a while.

 

[drbatts]

On my previous Grady the fridge was 12v. It stayed on all the time from when the boat went into the water in April until it came out at the end of November. The boat was plugged into shorepower at the dock and when off the dock the fridge always stayed on. The only time it ever got shut off was when we lost power at the dock. This created a problem as when this happens it will drain the house battery all the way down and the freezer will defrost. For this reason I would never keep bait in the freezer. I did have 2 klondike bars melt once which created a mess.