Thoughts on fridges on small boats for long distance cruising

Posted by BeeseChurgerMkII@reddit | sailing | View on Reddit | 27 comments

I’ve found this online and I’m debating whether I invest in a fridge or make do with a cool box for a westward circumnavigation from the UK.

I’m about to mould a new fibreglass cool box with room to allow 3 or 4 inch celotex and I can’t decide wether to make do with a well insulated box and have a grid in the bottom which I can put ice under.

Or I invest in this decent price fridge unit and install in the new Insulated box.

I know I could probably get by with ice when I’m around places with people and shops but it concerns me that I’ll have no way to cool down the box when on passage or in places like French Polynesia.

I’m only thinking I could run it on low just so it’s better than room temperature.

Will have 150ah of usable battery capacity and decent solar.

Anyone have any suggestions or experiences cruising without a fridge and how you got by long term?

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DogtariousVanDog@reddit

Regardless of the frigde (which is great, very efficient, effective, doesn‘t draw a lot of power) your battery setup is way too small. 150Ah is nothing in my opinion. I have 150 in my 33 foot weekend cruiser and it‘s not enough. What other power consumers do you plan apart from the fridge?

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Sea-Oven-7560@reddit

You can get a 600ah battery for about $600, if you have the money I'd buy two. Of course there's everything else, the solar, the upgraded alternator, all the charging controllers so there's more than just adding a bigger battery but 150ah total power is just not enough in my book -I'm a big fan of 2 is better than one and the big bag is better than the small bag.

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RedBeardWrasse@reddit

Doesn't the amount of solar matter more? I guess at 150Ah of battery you'd only have a day or two if you have overcast conditions, depending on other draws.

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DogtariousVanDog@reddit

And when it‘s not overcast, where does the solar power go if you have only 150Ah?

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1aranzant@reddit

it's wasted

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Groot_Calrissian@reddit

150ah will run a small refrigerator for ~12-36 hours depending on use and insulation. If you are eating and drinking out of it, you'll be opening it and losing some efficiency.

For planning you should have at least 3 days of energy independence from your batteries, and be capable of charging to full within 1 good sun day. You can expect to see around 70% of your nominal power output rating from solar panels, and depending on where you are and the weather, maybe 6 hours of nominal charging time in a day. You lose a lot of your 'ratings' to losses and inefficiencies. You'll also have other loads, leakage and overhead, and safety margin considerations in your planning process.

futurebigconcept@reddit

Mine looks similar, but I think it draws only about half an amp at 12 volts, so that would be 6 watts. I also have 150 ah house bank, lead acid. We make it work for a week by loading up block ice in the fridge, charging the batteries with the diesel 2-3 x per day, and mostly running the fridge when the diesel is running.

This is not a long-term solution for more than a week or so.

millijuna@reddit

We have a dometic icebox conversion on our Ericson 27. It’s great to have real refrigeration. Nothing quite like a cold G&T for happy hour.

Small_Dog_8699@reddit

Look into aerogel blankets - super efficient insulation without a ton of volume.

I put in a pair of Engel fridge drawers, separating the compressor/heat exchanger from the box as far as possible and wrapping them in aerogel blankets. They can each freeze or fridge. Its not a ton of power draw because of the extra insulation, gives me ice cubes and keeps perishables cool, and the install was dead easy, wrap em in aerogel, slide em into a drawer cabinet, strap em down, and wire em up.

Are you saying wrap the drawers? or are you lining the drawers with aerogel or just laying a blanket on top. This sounds cool I'm just trying to understand what you are doing.

Dorfbulle80@reddit

Depending on your batteries 150ah is a bit short for something that alone draws around 70w....

Fabricensis@reddit

150 Ah on a lead 12 V will run 70 W for 15 h with no other draws

Pretend_Cheek308@reddit

I've got 225ah of battery and run a similar 12v compressor setup no problem. If the weather is overcast for two days I do need to motor some to get through the tight spots. That being said my batteries are lead acid, if they were lithium I would probably go 4 days without a recharge. I have 500 watts of solar.

Scooter87942@reddit

Aplay1@reddit

Dometic makes small DC fridge/freezers. It’s a cheap option compared to a hard install.

Better price for good equipment with Iceco, and even better price with ok hardware from BougeRV.

The biggest concern I would have other than power budget (which you are not prepared for yet) is the acceptable angle during operation. If your refrigeration system is leaned over too far the liquid refrigerant will not gather in the sump and result in compressor over heating and burnout.

Otherwise, refrigeration is much nicer than ice. And if it breaks you'll still have an insulated ice box.

Western-Stock-1023@reddit

I have a 1987 Catalina 36. I have 200w of solar and 4 6V AGM batteries (wired in parallel and series to make two big 12v). I keep my boat in central CA (telling you for climate reasons) and I can tell you that it works well, but at the end of the night my batteries are low. If I keep a bag of ice in there as well, it works much better. The fridge keeps the ice longer, and the ice saves the battery. But it does draw about 6.5 amp hours when it’s on. Easily the thirstiest thing I run.

fuzzy_spanner@reddit

Great little fridge unit altgough depending on weather conditions your battery bank may be a bit small to run it full time

ManWhoIsDrunk@reddit

Do you have an onboard engine you could run to recharge in situations where the solar is not generating enough power?

Have you considered a wind generator in addition to solar?

70W at 12V is just under 6A, that could kill your battery in just over a day and a night if you don't manage to recharge.

Am I wrong in thinking the fridge only draws that power when it runs? Which it hopefully won't have to run 24/7 with a decently insulated fridge box?

Ok, let's say it is only running the compression cycle half the time, then it's roughly two and a half days before the battery dies without recharge.

Whole-Quick@reddit

OP, lots of naysayers here, but it could very well work out beautifully for you. And the price is amazing, that is a huge discount.

The manual for this compressor ( have a look!) isn't clear about actual operating current but claims power consumption in the range of 35 to 50 Watts depending on the evaporator, etc. So let's say 4 Amps at 12 Vdc.

You're building a well insulated box, so let's estimate the compressor runs 50% of the time. That works out to 48 Amp-hours per day, which isn't at all unreasonable for a basic solar+battery setup.

Now we don't know much about your electrical system other than 150 Ah of "usable capacity" which I would guess means about 200 Ah of lithium or 400 Ah of lead acid batteries.

You need to estimate your other electric loads and your generation capacity, then see if you have an energy budget for this fridge.

I cruise the Great Lakes in summer with 440 Watts of Solar and 170 Ah gross lithium battery capacity. Our little 4 Amp fridge compressor fits so well within our energy budget that we added a second one in a portable cooler style product.

Your situation is your situation, and some energy budget math will go a long way.

ICreditReddit@reddit

Personally I'd get a drawer freezer, and fill it exactly with plastic icepacks. The freezers don't need drain holes, so no through-holes to worry about. Get a highly insulated cool-box like a Yeti, put one icepack in it and the food. Swap the packs when the cool-box warms up, about every 3-7 days. The freezer will remain frozen without power for a long time if it's jam-packed full of frozen icepacks, and every time you're in port you hook up to shorepower and re-freeze everything. This means the warming/freezing cycle is only on inedible stuff not the food itself.

If you're on a long passage without shore-power, wait until you're under engine, or making excess solar etc, and turn the freezer on.

Fingers_of_fury@reddit

150 ah is too small for long distance cruising. I have 840 ah and it’s not enough in my opinion. I’m in the South Pacific and it’s not nearly as sunny as you would think. I have two of those dometic compressors on my boat. They are great. Keep in mind once you get to warm places like French polynesia the fridge will be running non stop and your power consumption will be much higher. Insulate the hell out of that box

NSAscanner@reddit

How much solar do you mean by decent? These fridges are great, but plan for it to use 60 Wh on average.

You may get lucky and use less than that - but you’ll need enough power generation for that load and whatever else you have

erikwarm@reddit

Maybe cheaper and better to but a camping fridge that can run on mains, 12V and gas (limited options for gas)

https://www.vevor.nl/auto-koelkast-c_10723/portable-refrigerator-1-94cu-ft-12v-110v-lg-compressor-12-24v-dc-vehicular-removable-handles-p_010396450836

https://www.jacksonsleisure.com/thetford/n4090/caravan/motorhome/fridge/freezer/wheel/arch/

Particular-Grab-2495@reddit

Fridges that can use gas are not compressor units but absorption type fridges. Efficiency is horrible compared to compressor type fridge.