Inverter to handle Refrigeration

[BoatandBeach]

So I've searched, but most of the threads that I find are 5+ years old.

I'm looking for recommendations for an inverter.

I need to power a residential (small house, not apartment sized) fridge/freezer combo, and a dedicated chest style
6 cu ft deep freezer. We're a big boat. I recognize this is more than your average cruising boat.

I'm installing 1000-1400Ah house bank this summer (golf cart batteries) and I have (2x) 120A Leese Neville alternators on each of my main engines. We're a power boat, so figure 3 days a week 6 hours a day motoring is a very conservative outlook.

Per a Kill-a+watt, the fridge/freezer consumes 150ah/24-hr period. The fridge on the Kill-a+watt is 17 years old, the chest freezer is 1 year old. A safe assumption is 250Ah per 24hr for both.

I had a Magnum Energy 2812 on a prior boat and liked it, but it was both inverter and charger for a much smaller
electrical load. I want a complete stand alone inverter for this boat, and I need pure sine for a very light load of computers for our work requirements.

Thanks!

[Chuck34]

My suggestion, since the fridge is 17 years old, it is probably inefficient. I'd replace it with a new, much more efficient 120/12 volt model leaving you with only one device to worry about and that can take a smaller, less expensive inverter. I've always heard that there is a fair amount of power loss using an inverter and this will lessen that loss.

Computer usage will be minimal.

[gonesail]

Originally Posted by Chuck34

My suggestion, since the fridge is 17 years old, it is probably inefficient.

what he said. so much better to have something that runs off 12 volts.

[john61ct]

Since you don't need to care about efficiency, just get another Magnum, bigger or multiples.

Or Victron, MasterVolt, Sterling, ProMariner

Xantrex is good but terrible CS attitude.

Vanner, Outback, Morningstar, Samlex and Tripplite also but not marine specific?

[hellosailor]

I see some confusion about perhaps just the laptop needs sine wave, but motors prefer it. Which would mean sine wave for everything.

There are a lot of inverters out there, few with stellar reputations, a few that seem to have problems crossing borders, and many Chinese clones that appear in different colors and brand names. Since "stellar" seems to be an illusive goal, one might suggest getting TWO inverters, so that when one inevitably does fail, at least you'll be able to run one of those (the fridge or the freezer) while the other is down. Yes, there will be some additional loss that way, but if the inverters are anywhere near load, that's not much.

If you knew the actual maximum inrush current for each box, that would help properly size the inverters. 24-hour averages aren't quite enough.

[44'cruisingcat]

On the fridge specs you should be able to find the power rating. It's probably something like 60 - 100 Watts.

Allow for 10 times that in your inverter sizing.

[Fore and Aft]

We live of the grid and have used a Latronics 2000 watt pure sine wave inverter to power our house for the last 12 years. Thats including a full size fridge/freezer and washing machine.
Chuck34 is right in saying the old fridge should be replaced. Here in Australia all our electrical apliances have an energy rating. Our fridge and washing machine are both 4 star out of 6 star on energy consumption.
If your boat is big enough have you thought about using 2 volt batteries wired into 12 volt like our solar system. The footprint is similar but the batteries are around 900mm high.

Cheers

[BoatandBeach]

Thanks for the replies.

The fridge isn't going anywhere until it dies, as removal requires a crane or gantry hoist and cutting a hole in the cabintop. I'm putting that job off as long as I can.
I've got a 20kw diesel gen set and a Honda 2000 suitcase gen onboard, so sticking with 120v fridge via inverter isn't a concern from a reliability standpoint. I just don't want to be burning diesel/gas 24/7 when away from the dock.

My 5 year old 30A ProMariner 30A charger died on me a couple days ago, and all it's ever been asked to do is float charge. So that brand is out.

I'll check out some of the others, thanks

[Palarran]

I guarantee that I can remove that refrigerator with a sawzall in less than one day and in chunks that will fit through a hatch.

I just installed a new one in my cat and it's been awesome. You will burn more power than you expect though. But what are you doing now to power it?

[janaconda]

The motor yacht next to me runs two new Samsung Digital Inverter Technology, 6 feet tall, 220 volt household refrigerators, both with separate freezers in top. They run only on solar energy with a single 1000 watt SNADI Pure Sine inverter. House bank is 600 watt solar batteries and he has 4 x 350 watt solar panels. Runs fine 24/7.
My setup is almost the same, 3 x 350 watt solar panels, house bank 900 watt and one Samsung Digital Inverter Technology fridge/freezer and same 1000 watt SNADI Inverter, that cost 110 USD here in the Philippines. I converted the 110 volt system on the boat to 220 volt. Everything 220 volt runs on this Inverter 24/7.

[Lepke]

I use Magnum a PAE-MS inverter/charger and run a large double door reefer, 2 small freezers, all lights except emergency and nav, tv and so on. But it takes enough batteries. Mine is 48v and I have 3 banks. I can go 2-3 days depending on how many aboard. Solo about a week, but make water and run a generator for an hour about every other day. No AC needs.

[mako]

Originally Posted by BoatandBeach

Per a Kill-a+watt, the fridge/freezer consumes 150ah/24-hr period. The fridge on the Kill-a+watt is 17 years old, the chest freezer is 1 year old. A safe assumption is 250Ah per 24hr for both.

Have you measured your chest freezer with the Kill-A-watt? I have a 5.3cf junkie unit and measured it at 900 watts daily (75 amps at 12vdc). Perhaps yours is more efficient.

You could likely cut the refrigerator energy use in half with a modern unit, maybe even less. It might be worth figuring out how to chop it up and dispose of it without cutting a hole in your deck.

[john61ct]

For those who **are** more concerned with efficiency, the fridge / freezer models by top makers for the Aus / NZ and Euro markets, are much much less thirsty than those sold to consumers in NA.

To the point that many Aussie forums have documented **greater** efficiency

Ah / 24hrs per volume capacity

using household 220V fridges than with 12V compressor portables, even with inverter losses.

I bet insulation has a lot do do with that.

[smac999]

With a 1400ah house bank and a 20k gen. You want about 300a of charging.

So get a marine inverter charger. Forget the inverter only. You need the charging. . Plus 2 more 100a chargers. Ideally running at 240v to help balance the phases.

Yiu will need to measure / read the draw of the fridge and freezer. I’m guessing you’ll want. 3000w do you can also run other things while the fridges are running.

Magnum and victron are both good.

[Seman]

I have installed a 110V mini bar fridge,92W at 110V running.
The dedicated 750W/1500W modified sine wave inverter would trip the overload during start up.
bought a 1500W/3000W inverter, starting and running well now.