DC Fridge Operation - Not sure how it works

[Rick K]

Hi all,
New to the forum, new to Sea Ray boats too! I just picked up a pristine '81 SR245, and the original fridge had been replaced with a small AC fridge. Works great when at the dock, but of course doesn't when away.

There's no power panel/inverter/converter system on this boat (just shore hooked into 3 recepticles), and wife wants a Norcold AC/DC fridge installed.

I hear that you can wire the AC/DC fridge directly to the house batteries, etc., and that the fridge will switch automatically when the shore power is cut.

I say leave the fridge that's there and mount an inverter and swap plugs when leaving the dock.

Is the AC/DC fridge even a possibility for this boat?

Thanks,
Rick

 

[Kay Lee]

The Norcold fridge will switch automatically according to the owner's manual. My boat has a circuit breaker for the AC side and a switch for the DC side for whatever reason. The Norcold draws about 3.5 amps from the batteries so that works out to be about 44 watts. I suspect your AC only fridge draws a lot more power. I you chose the inverter route, you may find that a true sine wave inverter will be required and now you're talking about $200 just for a 200 watt model. Find out what the power consumption of your AC fridge is and then maybe we can determine if it's feasible to run it off of batteries.

Larry

 

[dpmulvey]

I am assuming you have a battery charger on the boat that tends to the batteries when plugged into shore power. Personally, I would stick with the dorm fridge, an inverter and a seperate battery for the fridge.

When all is said and done, you will still be out less money than a 12/120 fridge. If your Admiral insists on a 12/120, I would opt for the Tundra. They are quieter and draw less power than a similar Norcold.

Of course you could always go for cold plate technology.

 

[Rick K]

Thanks for the replies...

Larry, I have no clue what that little dorm fridge draws. It's not the new, compressorless style, it an older one and it keeps stuff borderline frozen. I'm going to have to assume it's a power hog.

And going with the sine wave inverter along with all the wiring, etc., seems like a lot to do just to run a fridge.

David, Admiral wants 12/120, so yeah, I'm stuck.

What I do need to do is get a better charger; there's a small 10 amp charger that's only hooked up to one battery, and I have to assume that the alternator charges #1, #2, or both, depending on where the battery switch is. Not the best setup in the world, but it seems to work.

Personally, I'd rather have an "intellegent" charger, a third battery, and go that route with respect to the fridge.

Gotta have that fridge though, we spend way too much time away from the dock not to keep stuff cold!

Thanks again,
Rick

 

[Kay Lee]

Another option is a 12VDC thermo-electric cooler. I used one on my cuddy for many years and was very happy with it's performance. It isn't a freezer, but if you just need a fridge it's something to consider. They can usually be gotten for about $100 or less.

Larry

 

[Rick K]

Hi again Larry,
I have one of those actually, new in the box. Kind of apprehensive about using it, as I know they have a tendency to LOVE draining a battery in no time! :grin: The admiral picked it up for my fishing boat, but I never got a chance to use it.

I really have to revisit my batteries & charger, and get a better setup as far as chargers go. I would like nothing more than to hook everything up, and forget about it for the season.

One of the nice things about this boat, is that it cost half of what we had actually saved up for, so we can spend the OTHER half on cool stuff, like accessories, battery chargers, and other things the admiral has deemed unnecessary. And I'll have that $50.00 Sea Ray T shirt if it kills me!!!

Thanks again for the reply/advice. Always appreciate it!

Rick

 

[rondds]

Rick
Have you priced the AC/DC fridges? They ain't cheap when compared to a straight AC dorm fridge.

 

[dpmulvey]

Rick;

With respect, does your wife understand power management while away from the dock?

On my Regal, I had a Norcold 12V only fridge that would suck the life out of a battery in 24 hours. When on shore power, IIRC, the fridge ran off the one of the charger banks or the batteries charged faster than the fridge could drain them. A straight 12VDC fridge is less expensive than a 12/120 fridge.

Another thought is to make a small wooden container with holes in the lid and put some dry ice in there. It will keep things cold for a couple of days and reduce the number of times the compressor cycles.

So, you will need a 1-Both-2 battery switch at minimum so you have a means of starting after being on the hook all day draining one of the batteries with the fridge, stereo, etc.....

Better yet would be a 1-Both-2 switch to your house / starting bank and a 3rd battery with an on/off switch dedicated to the fridge. Couple the entire system to a quality battery charger to ensure you have ample juice when departing the dock and more importantly, ample juice to return.

 

[NorCal Boater]

My boat had a dual voltage Norcrap fridge that died right after we boat the boat. The price for a dual voltage replacement was over $1200 so I bought a 120 volt only that fit the hole for $150.

Last year I added a Xantrex Pro 1800 watt modified sine wave inverter with a built in transfer switch and 2, 6 volt golf cart batteries. I bought the inverter on ebay for about $280 and rhe batteries at Costco for $78 each.

Installation was not difficult and the 1800 watt also allowed me to add my TV and DVD player to the inverter circuit.

Total investment was about $500 less the fridge. Now if this fridge dies I can go buy another for a buck and a half.

 

[Rick K]

Hi guys,
Nah, the wife has no clue, and of course, no offense taken.

She wants what she wants, and you all know what THAT means! :smt089 <-- me.

I did find a No-cold for about $650, and the Tundra was twice that. We have that little dorm fridge down there now, and that works great - while at the dock.

This is quickly becoming a pain-in-the-bilge; I think the best way to approach this, is to perhaps point the admiral in another direction, and divert her attention away from the fridge!

I know that this is an older boat, and didn't come with all the bells and whistles. Heck, I'm still trying to figure out why in the world someone took out the holding tank and threw a porta potty in there!

I know I will find something that will make this work. Since I don't have a lot of other things to do to the boat, I'm going to make this a priority. Of course, when I've reasearched everything and finally get it hooked up, I'll be able to power a small city. (and I wonder why they call me Mr. Overkill)...

Thanks agian guys. I am gonna check out that inverter and perhaps start from there.

Rick

 

[dpmulvey]

<"...We have that little dorm fridge down there now, and that works great - while at the dock....">

It's late in the season for NY. Deal with it over the winter. You may want to purchase Nigel Calders Book on electricity for boats. He breaks extremely large and complex things down to layman terms in small packages. It was one of the best $40 I spent on reference material.

 

[AnchorsAweigh]

My boat had a dual voltage Norcrap fridge that died right after we boat the boat. The price for a dual voltage replacement was over $1200 so I bought a 120 volt only that fit the hole for $150.

Last year I added a Xantrex Pro 1800 watt modified sine wave inverter with a built in transfer switch and 2, 6 volt golf cart batteries. I bought the inverter on ebay for about $280 and rhe batteries at Costco for $78 each.

Installation was not difficult and the 1800 watt also allowed me to add my TV and DVD player to the inverter circuit.

Total investment was about $500 less the fridge. Now if this fridge dies I can go buy another for a buck and a half.

Good call NorCal, thanks for helping me with my decision. I pulled my dual voltage fridge out this spring and bought the 12v cooler. It works good except it is quite power hungry. I already have 1 superbank of batteries (from a solar system) and plan to add another for both motors. I have the Xantrex 1500 watt inverter ready to go, hoping to be able to use all the other little amenities, like a coffee maker! The next thing I was going to add was a 1000 watt generator in case I do kill all the batteries. I guess another battery selector switch would work with more batteries but you can pick up these little gens for $300-$500 depending on brand. All said and done (with a new 120v fridge) I will be way under the $1200 it costs for the replacement fridge, and as said I can do more things with less money.

 

[Rick K]

Went with the Xantrex HF 1800 Inverter/Charger. Not gonna mess with it this year, haul out is right around the corner. I'll have plenty of time to get this installed once she's on the trailer and back in the driveway.

Appreciate the advice everyone has given. Thanks!

Rick