Fridge Question

[Holy Shamolee]

I need a new fridge for my boat. Very expensive item.
Why not buy a Danby fridge from Walmart for 99.00
Buy a 1000 watt inverter for another 150.00.
And a guy is set for 250.00 instead of 900.00.
I can't be the first guy to think of this..

WHY NOT!!!!

The fridge in question needs 85 watts to run . It surges when it starts and draws 150 watts. The inverter will easily take care of this unit... And More..

 

[cpubud]

Re: Fridge Question

if you have the battery bank to run it go ahead. some things are picky with inverters ,sine waves have to be right to operate properly.

 

[crabby captain john]

Re: Fridge Question

Thought of that when the 3 power fridge in the motorhome went out. Decided to spend $1300 instead.

 

[dan t.]

Re: Fridge Question

Exactly what I did,1.7 cubic ft danby fridge, 1000 watt inverter, 2 group 27 deep cycle batterys, I have a 65 amp alternator on my boat,seems to be adiquate. I am good for about 22 hours then the inverter starts to beep on startup, it takes a good hours running to bring the batterys right up. Before a trip I try to plug in to shore power for at least 1 hour to get the fridge cooled off. I run it at the highest setting when on shore power and while running the boat, then turn it down to about 25% when on the hook. Make sure you put in a switchable circuit breaker between the batterys and the inverter, the inverter still draws a small amount of power even when switched off

 

[agallant80]

Re: Fridge Question

You can if you want. You just will be drawing more power. If you have a large bank, generator, or can hook in to shore power then its not that big of a deal. I find the little fridge on my boat pretty much useless and use it more so for wine and soda storage. I use a cooler for everything else.

 

[shrew]

Re: Fridge Question

The conversion from 12V to 110V is going to be very, very expensive in regards to the amoutn of amps required. Going straight 12v to 12v will take significantly less amp hours from the battery bank to kep the fridge running. Also consider if you want to eventually sell the boat. Many will not consider a boat that has a residential fridge replacing the dual Voltage fridge. I'm already looking at spending another $1000 to make the boat right AND this speaks volumes about how the owner has addressed the rest of his costly repairs and maintenance.

Do it on the cheap, and I'll assume that is how you maintained the entire boat all the time.

 

[spdracr39]

Re: Fridge Question

Also consider if you want to eventually sell the boat. Many will not consider a boat that has a residential fridge replacing the dual Voltage fridge. I'm already looking at spending another $1000 to make the boat right AND this speaks volumes about how the owner has addressed the rest of his costly repairs and maintenance.
Do it on the cheap, and I'll assume that is how you maintained the entire boat all the time.

Agreed. There are two ways to do repairs the cheap way or the right way. Neither is always right or wrong but it is a reflection of how the maintenance is dealt with.

 

[Chris1956]

Re: Fridge Question

According to the internet, an inverter is most efficient (80%), when it is being used at near it max power output. It does draw power when not being used at all, so it would need to be disconnected at that time. Larger inverters turn themselves off.

Inverters that produce less than a pure sine wave, will cause the appliance to use more power. So it would seem that to power that fridge, get a 200W inverter, with the best sine wave output you can find. That should have enough output to power it, use the least amount of power run the inverter, and thereby maximize the efficiency.

 

[Bamaman1]

Re: Fridge Question

I take it your old refrigerator is an ammonia RV/Marine type unit? And a new unit will cost $1K or more? They're notorious for dying every 10 years due to rusting parts.

You can easily find repair shops that rebuild any ammonia style refrigerator/freezer.

 

[shrew]

Re: Fridge Question

^^ I believe those numbers are very conservative. Best Case scenario, your using 20% more Amp hours to power the same fridge for the same time period. I strongly suspect it is more. That is too much loss for me, but everyones needs and values are different.

 

[dan t.]

Re: Fridge Question

Actually the draw is about 6 amps with a 15 amp surge on startup, a 200 watt inverter wont even start it, I tryed a 450 watt and even it wont do it unless the motor is running at 1500 rpm. As far as the price of the fridge reflecting the quality of maintainance , what a pile of BS.Just because you dont have 1200 for a dual voltage marine fridge doesnt mean you slack off on your maintainance. Is a boat better maintained if it has a $400 VHF rather than a $100 one, I dont think so. I chose to go this route and spend the $800 or $900 on fuel and Rum. Boating is about having a good time, not about keeping up with the Jones. (My apoligies to anybody with the name Jones)

 

[shrew]

Re: Fridge Question

A $1000 in a boat is a 'blip'. If you have to choose between replacing equipment with the proper equipment OR gas and booze, then this absolutely leads me to wonder what other expensive repairs were done on the cheap. How many non marine parts are in there? Boating is expensive. If $1000 bill is too much, then boating is not your budget.

 

[H20Rat]

Re: Fridge Question

Actually the draw is about 6 amps with a 15 amp surge on startup, a 200 watt inverter wont even start it, I tryed a 450 watt and even it wont do it unless the motor is running at 1500 rpm.

I was thinking the same... When it comes to starting a big electric motor, cheap inverters have an EXTREMELY hard time dealing with it. They are meant for nice even resistive loads. Take the advertised running current, and go 5x to 10x as large for the startup current. (and that is assuming very short and very large cables going to the battery(s). Having the voltage drop on the 12v side greatly affects an inverter also)

Also worth mentioning that cheap inverters are not marine rated. Marine rated inverters are spark protected, and usually about double or triple the cost of a non-marine version.

 

[dan t.]

Re: Fridge Question

I was thinking the same... When it comes to starting a big electric motor, cheap inverters have an EXTREMELY hard time dealing with it. They are meant for nice even resistive loads. Take the advertised running current, and go 5x to 10x as large for the startup current. (and that is assuming very short and very large cables going to the battery(s). Having the voltage drop on the 12v side greatly affects an inverter also)

Also worth mentioning that cheap inverters are not marine rated. Marine rated inverters are spark protected, and usually about double or triple the cost of a non-marine version.

I dont think marine rating has anything to do with it unless it is in the engine compartment, I mounted mine in the cabin 3 ft #0 cable.If you had to have spark protected in the cabin how would you light the stove?

Shrew, you just dont seem to get it, would you rather sit at the dock with your $1000 fridge or go boating with a $250 fridge? I know what I would do.

 

[H20Rat]

Re: Fridge Question

I dont think marine rating has anything to do with it unless it is in the engine compartment, I mounted mine in the cabin 3 ft #0 cable.If you had to have spark protected in the cabin how would you light the stove?

Correct, needs to be marine rated if mounted where there is a chance of explosive fuel. Generally you want the inverter near the batteries, which are near the engine. If you do the alternative and run big enough cable, it isn't a problem.

 

[UncleWillie]

Re: Fridge Question

...The fridge in question needs 85 watts to run . It surges when it starts and draws 150 watts. The inverter will easily take care of this unit... And More..

Actually the draw is about 6 amps with a 15 amp surge on startup, a 200 watt inverter wont even start it, I tried a 450 watt and even it wont do it unless the motor is running at 1500 rpm...

85 watts sounds very optimistic unless we are talking about a solid state cooler. That isn't much cooling power.

6 amps is the same as 750 watts. A 1000 watt inverter would be a bare minimum to get it to start and run.

 

[Southtowns27]

Re: Fridge Question

http://www.bestbuy.com/site/koolatron-super-kool-1-7-cu-ft-ac-dc-compact-refrigerator/2099128.p?id=1219068847133&skuId=2099128&ref=06&loc=01&ci_src=14110944&ci_sku=2099128&extensionType={adtype}:{network}&s_kwcid=PTC!pla!{keyword}!{matchtype}!{adwords_producttargetid}!{network}!{ifmobile:M}!{creative}&kpid=2099128&k_clickid=351f07e1-575c-e548-ab0d-000045a969ec

Here you go.. Not sure how well it will hold up, but would probably be fine for weekend use

 

[frantically relaxing]

Re: Fridge Question

Most 12v/120v marine refigerators are freon based (using compressors) and not ammonia based (using heat strips or propane flame).

And I've measured the draw on the small fridge in our Party Cruiser, 5.5 amps. Not much different than 6...

 

[smokeonthewater]

Re: Fridge Question

An interesting note here... above it was mentioned that he gets 1 day on two batteries with his inverter... I get 2-3 days on 2 batteries with my marine fridge.. You gotta remember that the inverter draws power the whole time it's turned on but the 12v fridge ONLY draws power while the compressor is running.

Also, Dan, you took the cheap maintenance comment WAY too personal... The statement WAS accurate but only as a generalization.... If I am looking to buy a boat and I find two similar boats... one of which the owner has put nearly $1000 worth of maintenance costs I can see plus who knows how much I can't see int "gas and beer" instead of the boat and the other shows a "no expense spared" maintenance history evidenced by the "$700 vhf" on the dash then obviously the second one has a VERY high chance of being the better boat and the better buy.....

Does this make you a bad person for the choice you made? Of course not and it doesn't make you any less worthy of a boater... You are simply satisfied with a slightly less fancy fridge and of course you have to accept that it hurts the resale value of your boat at least a little.... Who cares.... You are boating with a working fridge. I wouldn't buy a new dual voltage fridge either but then I have salvaged 3 of them from boats I parted out and currently have a spare so I'm a step ahead aye.

 

[Holy Shamolee]

Re: Fridge Question

If these fridges run on 12VDC and 110 VAC, then they must have some kind of inverter or converter built in. Is a marine fridge just a normal fridge with an inverter built in.? I'm not trying to be cheap, but I don't want to just burn money if it isn't necessary.