Best option to power 15CF 120v Refrigerator for a few hours

[Zeus]

Boat does not currently have a generator and some of my upcoming passages may be upwards of 8 hours. What are the best temporary options to power the refrigerator while underway? I have seen some of these portable LiFePo4 options but I don't know the actual draw of said refrigerator. Thanks for any help.


EDIT: Its actually 17.5CF. There is a Xantrex charging system in the boat but I don't think its wired to invert power from the batteries. Boat only has two 8 D's for port and starboard starting and also act as house batteries.

 

[DavidM]

A 15 cu ft, 120V fridge will draw a lot of power. You will need an inverter to power it with DC and supply it with at least 5 amps DC on average.

While underway the alternator on your propulsion engine can supply that DC, but preferably if it is a high output type with an external regulator. But even with little alternator charging, a 100 Ah house battery will definitely last 8 hours while supplying DC to your fridge.

Some Li based power packs can do it for 8 hrs if they have at least 500 watt hours of capacity.

David

 

[Mako]

OP is this boat new to you, how has the previous owner used the refrig when sailing previously?

 

[Zeus]

OP is this boat new to you, how has the previous owner used the refrig when sailing previously?

Yes, new to me and I don't think the previous owner used it much in the absence of the genset. Its an old Bertram which were notorious for deck leakage on top of the gen. Until I can take the time to remedy that, its not worth installing a new gen.

 

[CharlieO.]

I have been thinking about this also, I was wondering about just hooking an inverter to my alternator charged bank. I don't have a fancy alternator though and only 1 battery bank of 2 batteries for my start/house supply.

 

[O C Diver]

You need to know the 120VAC amperage draw of the refrigerator. My guess is that the refrigerator (if made in this century) will probably draw less than 4 amps but may have long duty cycles. A Victron inverter would be my choice. In a worse case scenario, the inverter would cost around $300 and consume about 40 amps 12VDC (assuming it draws 4 amps at 120VAC). Until we know the amperage draw, it's difficult to go further.

Ted

 

[Zeus]

You need to know the 120VAC amperage draw of the refrigerator. My guess is that the refrigerator (if made in this century) will probably draw less than 4 amps but may have long duty cycles. A Victron inverter would be my choice. In a worse case scenario, the inverter would cost around $300 and consume about 40 amps 12VDC (assuming it draws 4 amps at 120VAC). Until we know the amperage draw, it's difficult to go further.

Ted

Here is the badge from the inside. Doesn't say much.

 

[Gdavid]

Keep in mind that the energy consumption estimates for that household fridge assume it is in a climate controlled environment ~72 Degrees. On a boat, the fridge is frequently working in a much warmer environment, so the insulation is at an disadvantage as well as the condensor coils. This is excacerbated if you leave the boat closed up while you go ashore. Do everything you can to help the fridge out like providing plenty of circulation space around it and keeping the cabin ventilated.

Boaters frequently complain about poor fridge performance without paying much attention to the tortured environment onboard. I still think you are money ahead by sticking with a 120V fridge and inverter/battery or integrated mobile power supply (as long as it is a stable chemistry). The savings compared to a 12V fridge will pay for most of the inverter and it is much easier to replace a standard 120V fridge if necessary. If you were doing a lot of off grid cruising with extended time at anchor, a build in ice box with cold plates and a sea water cooled condenser setup would eventually pay for itself but for most coastal cruising practices, the setup you are headed towards is a reasonable solution.

 

[Portage_Bay]

To find the AC power draw you could use a Kill-a-watt meter. It will tell you instantaneous power draw at any moment in time as well as total consumption over time. Then to estimate DC power requirement multiply the AC power required by 110% and you'll be pretty close.

 

[O C Diver]

Here is the badge from the inside. Doesn't say much.

Part of the badge was clipped from the bottom. Is there more information. As mentioned, the Kill-O-Watt meter would be a more precise method to measure watts over a day or day or two and will probably also give you maximum amperage draw also. I would run it for a week or so in case there is an intermittent maximum amperage draw such as a defrost cycle.

Ted

 

[Zeus]

Part of the badge was clipped from the bottom. Is there more information. As mentioned, the Kill-O-Watt meter would be a more precise method to measure watts over a day or day or two and will probably also give you maximum amperage draw also. I would run it for a week or so in case there is an intermittent maximum amperage draw such as a defrost cycle.

Ted

It only adds that it wants a 120v/20amp circuit. No other details. Measuring it precisely with the device you mentioned is probably the best bet.

 

[ofer]

a cheap 2000 watt portable generator running outdoors with a gas tank is what i would do.

also there are some that will run on propane.

 

[Don L]

It only adds that it wants a 120v/20amp circuit. No other details. Measuring it precisely with the device you mentioned is probably the best bet.

You sure your boat doesn't already have a main ships inverter??? If it does, turn it on and while you are traveling it will be powered from your alternators.

 

[Zeus]

You sure your boat doesn't already have a main ships inverter??? If it does, turn it on and while you are traveling it will be powered from your alternators.

Its possible that the newer battery charger is also an inverter. I'll have to check.

 

[O C Diver]

It only adds that it wants a 120v/20amp circuit. No other details. Measuring it precisely with the device you mentioned is probably the best bet.

There's probably another sticker that look like the one below. The Kill-O-Watt meter would give you the consumption though.



The electric information on this refrigerator sticker is on the left side about half way down.

Amps- 3.30
Volts- 115
Hertz- 60

Ted

 

[tiltrider1]

I have been reluctant to chime in. I personally find it unacceptable to have two 8D’s act as starting and house Bank.

However, this being a new to OP boat, I fear that OP might not correctly understand the electrical set up.

Assuming he is correct, I wouldn’t even leave the dock without changing the set up to a starting baNk and a house bank. One 8d is more than adequate to start both engines. This would leave the seconD 8d as a house bank. In an effort to save money I would wire onE alternator to each bank.

I would then move the battery charger to the house bank. For the refrigerator I would get an inexpensive 1500 watt inverter and wire it to the battery, don’t forget to add circuit protection. Now the fridge will always be powered either by the charger, alternator or battery.

Now I offer this as a temporary solution as a way to get the boat home were a proper permanent solution could be installed.

 

[Pete Meisinger]

I know I'll say it wrong but you can figure it out. There is a new "gadget" on the market. It is called a "Jack-O" or jackamo or something similar. It is basically a battery pack with Lithium batteries. When I say gadget, I am tongue in cheek, it will cost you about $3,000.

I supposedly will basically run nearly a whole house in the event of power failure for a day.

It is light, like under 30 pounds and small, like a small cooler size.

I often switch off my refrigerator at anchor to preserve the batteries. As long as it stays closed there is pretty small temp increase.

pete

 

[Zeus]

I have been reluctant to chime in. I personally find it unacceptable to have two 8D’s act as starting and house Bank.

However, this being a new to OP boat, I fear that OP might not correctly understand the electrical set up.

Assuming he is correct, I wouldn’t even leave the dock without changing the set up to a starting baNk and a house bank. One 8d is more than adequate to start both engines. This would leave the seconD 8d as a house bank. In an effort to save money I would wire onE alternator to each bank.

I would then move the battery charger to the house bank. For the refrigerator I would get an inexpensive 1500 watt inverter and wire it to the battery, don’t forget to add circuit protection. Now the fridge will always be powered either by the charger, alternator or battery.

Now I offer this as a temporary solution as a way to get the boat home were a proper permanent solution could be installed.

While I wholly agree, this setup is more common than you think. My last Marine Trader was the same way with the exception of a 3rd 8D as the generator starting battery. House was still the starting 8Ds. I don't like it either and it will get a full overhaul to my liking once berthed here in Florida rather than Virginia Beach.

 

[Zeus]

I know I'll say it wrong but you can figure it out. There is a new "gadget" on the market. It is called a "Jack-O" or jackamo or something similar. It is basically a battery pack with Lithium batteries. When I say gadget, I am tongue in cheek, it will cost you about $3,000.

I supposedly will basically run nearly a whole house in the event of power failure for a day.

It is light, like under 30 pounds and small, like a small cooler size.

I often switch off my refrigerator at anchor to preserve the batteries. As long as it stays closed there is pretty small temp increase.

pete

I looked at several of these. They are portable and pricey, but I'd rather something more elegant eventually rather than $3k right now. I really like the server-rack style LiFePo4 stuff + inverter. (I know, more than $3k, but a nicer setup in the long)

 

[Zeus]

There's probably another sticker that look like the one below. The Kill-O-Watt meter would give you the consumption though.

View attachment 139587

The electric information on this refrigerator sticker is on the left side about half way down.

Amps- 3.30
Volts- 115
Hertz- 60

Ted

Thanks, I'll look for it.

 

[Zeus]

Thanks everyone for all the responses and input.

 

[Jeff F]

You don't need extra battery power if you're underway. Use an inverter. The extra load will easily be covered by the alternators.

It's only at anchor that batteries matter. I didn't take that to be the OP's challenge.

 

[Zeus]

You don't need extra battery power if you're underway. Use an inverter. The extra load will easily be covered by the alternators.

It's only at anchor that batteries matter. I didn't take that to be the OP's challenge.

Its marina-to-marina travel for us as transient. No anchoring is planned.

 

[mvweebles]

Pure sine wave inverters are relatively inexpensive. The GoPower ones are very good and carry appropriate UL Listing for grounding.

Here's a 1500w model, though even a 600w model would cover your fridge. There are less expensive PSW Inverters than

https://invertersrus.com/product/gopower-gp-sw1500-12/

Here's a 600w version for a bit less
https://invertersrus.com/product/gopower-gp-sw600-12/

GoPower, but GoPower is rated to continuously produce full output for 24-hours. I have a Wagan 1500W inverter in my camper van which is also pretty good, and a bit less. I only have a small 120VAC panel so was able to easily wire a rotary selector switch to select between shore and inverter. Kisae inverters also have a decent reputation. In my opinion, avoid Renogy at all costs (and they are attractively priced). Their failure rate is relatively high, and their RMA support especially awful.

Simple install would be to wire to battery bank (with circuit protection on positive lead from inverter to battery) and just use an extension cord from fridge to the inverter. Achilles Heel would be if you anchor - depending on your battery capacity and setup, would be possible to drain batteries without knowing it. A Victron SmartShunt for around $130 gives very valuable use/state-of-charge information.

If your use case is really limited to underway between shore power plug-ins, thr above will do fine at minimal cost.

Good luck.

Peter

 

[CharlieJ]

I operated the 16.5 ft^3 household refrigerator for years on a battery>inverter/charger system including 3.5 years in the Eastern Caribbean. The only electrical load of any significance was the refrigerator that we installed immediately before heading down island. The boat was never air-conditioned while underway.

The amp-hour removed and replaced was monitored with a shunt-based battery monitor and was consistently 550Ahr/24-hour day or 23Ahr/hour which works out to be about a 46% on/54% off cycling.

Assuming the same performance from the OP's system, 8 hours running will consume 183Ahr. A single 8D lead acid battery in good condition is capable of producing a nominal 220Ahr but should not be drawn down more than to a 50% state of charge meaning only 110Ahr should be taken from the single 8D.

Of course if the alternator charging that battery is in good condition and can maintain an output current of > 23A, the system will work. But, and there is always a but, the alternator needs to be able to produce this constantly. In my opinion a stock, internally regulated, older alternator will not be able to produce this amount of power for the duration of an 8 hour voyage.

 

[O C Diver]

Of course if the alternator charging that battery is in good condition and can maintain an output current of > 23A, the system will work. But, and there is always a but, the alternator needs to be able to produce this constantly. In my opinion a stock, internally regulated, older alternator will not be able to produce this amount of power for the duration of an 8 hour voyage.

From the original post, the boat has 2 engines. It's a pretty simple matter of choosing the engine with the lowest house loads. Considering the age of the boat, it probably has alternators that are capable of handling incandescent lights, older less efficient electronics, and other high amperage power consumers. It would be pretty simple to also determine the output amperage of the alternators.

Ted

 

[Mako]

Thanks @CharlieJ for the numbers, they "feel" right as well for a typical domestic fridge. Switching to a digital inverter model (LG, Samsung, etc.) would drop that daily energy draw down to about 1kW-hr instead of 1.5

That's what I used when I was overseas. The energy-use labels on the fridge at the store were quite accurate I found. If OP opted to go this way then a single 8D battery would be sufficient for a single day's usage (1000w = 83Ahr + 20% losses = 103Ahr daily), resulting in savings to offset the purchase of the new fridge.

 

[Portage_Bay]

Depending upon the alternators and running load it may work. OP is marina hoping so it probably will work because the batteries should be at 100% on departure. All he has to do is break even enroute to the next marina.

Do be careful, older OEM internal regulated alternators can be in the 50 AMP range, real world capable of about 25 AMPs. OP will need to know running load so see if there is any left over for the inverter.

We ran into that problem with 55 AMP internal regulated alternators. Obe charging house bank, one charging start batt. But we anchor out so the house bank is down in the morning and needs a good charge. Trying to run much off the inverter while underway left the batteries undercharged upon arrival at the next anchorage requiring long gen set run times to get the house bank back up. For now, until we upgrade the alternators, we run the gen while underway. It's less annoying that running at anchor.

You don't need extra battery power if you're underway. Use an inverter. The extra load will easily be covered by the alternators.

It's only at anchor that batteries matter. I didn't take that to be the OP's challenge.

Its marina-to-marina travel for us as transient. No anchoring is planned.

 

[CheckMateTim]

My wife and I use an EcoFlow DeltaMax to power up the fridge/freezer for quite a few hours at a time and also use solar to recharge it

 

[C lectric]

Look up GE fridges on the internet. With model number you likely can find the electrical listings. It will take a while maybe
OR
just get a KillaWatt.