Want to last the WEEKEND (refrigirator batteries)

[kenrahe]

Want to know how i should have my batteries wired .My refriged seems to run down my power in less than a day have 3 dual purpose marine batteries one for motor rest for boat.want it to at least last the weekend with worry of dead batteries.

[Stumble]

Ken,

It doesn't sound like you have a wiring problem so much as a capacity problem. Marine refrigirators are notoriously high draw items that require large battery banks to keep them running. Which is why most cruisers only run them while the engine or generator is on. For a weekend cruise best practice would probably be to run the refrigerator while at the dock or under power to freeze the plates solid, then you should proably be able to get at least a few days of cold from them. If you really want to be able to run it just off of battery power then you need to install a battery bank large enough to handle the current draw.

Just as a rule of thumb, for an overnight use boat the recommendation is to have at least 200ah of battery dedicated to the refrigerator. Or 2 60lbs DEEP CYCLE (Not marine, or multi use) batteries, figure these should weigh about 120lbs. Plus you need enough battery power for your other current draw whatever that happens to be.

[hoytedow]

Put as much frozen water bottles as possible in frig and don't use the door as a fan.

[F3M4]

Coming from the car audio background, I know a little about this problem.
My advice would be to find some UPS style batteries online. Like stumble said, your best bet is to obtain around 200ah. This can be accomplished with ONE UPS style battery if you have somewhere to put it.

http://www.batteryspec.com/cgi-bin/c...nk&product=113

Downside is that it would be heavy.

[Ike]

I would go with what Stumble said. Besides you don't have to leave the fridge on all the time, and frozen water or vegetables in plastic bags will keep it cold for a long time. Put a thermometer on it and checked it every couple of hours. If it gets up to 38 degrees or more run the fridge til it cools down, then turn it off. The ideal temp for a fridge (not a freezer) is 35-38 degrees. If this a marine refridgerator it should stay cold for a long time. Keep the door shut as much as possible. Everytime you open that door the cold comes out and warm goes in.

[CDK]

The average boat fridge with a clean condenser and correct gas level consumes 0.7 KW in 24 hours, more if dust etc restricts the airflow.
That means 60 Ah for a 12V system.

Because it is unwise to drain batteries below 60% charge, you need at least 100 Ah capacity for each day the fridge runs on battery power.

[missinginaction]

I'd agree on the capacity idea. A man that I work with has been involved with solar/wind turbines etc at his home. He's not a boater but he's interested in becoming energy self-sufficient at his home.

This gentleman has helped me on my boat and he's suggested that I consider 6 volt golf cart batteries for my house bank. He argues that they are relatively inexpensive, are much easier to handle than large capacity 12 volt batteries (lighter) and are ruggedly built. It's a simple matter to series a couple together. With the multiple output chargers we have available today it's very easy to set charge routines for a small starting battery and these deep cycle batteries as well from the same charger. Take a look at an example ......you can order appropriate terminals so that you can easily make your series connections, install appropriate battery terminal fuses and then connect the batteries to your DC main panel or battery switch.

http://www.trojanbattery.com/Products/T-145Plus6V.aspx

MIA

[CDK]

Sound advice MIA, less cells in a pack is better for your back and ultimately for your wallet also if one cell fails and you have to discard only two good ones instead of five. For the same reason batteries for solar powered communications repeaters often are built from single cells.

[capt littlelegs]

You'd be better off buying a Danfoss compressor type fridge, these are very good and use half the current that the absorption type use. You still need sufficient battery capacity only not so much.

http://www.bradtech.ltd.uk/cruise42.asp