Stupid Question?

[Chef David]

Maybe a stupid question...
I need to put new batteries in my boat, a 1966 Islander 33. Must I use 12V that are specifically designed for marine applications? I have a friend who can provide me with an endless supply of SUV/RV batteries for free. Is it worth it to even consider this?

Thanks!

[Island Time O25]

For a house bank you can do 6v golf batteries installed in a series to get 12v if you can get them cheaply enough.

The "marine" moniker on a starting battery is often a negative as it signifies a battery which is often not spec'd for very cold temps. After all how often do you get a -20F or colder ambient air temp on a boat which is on the water? But most car batteries are made to handle wide range of temps including extremely cold temps.

[skipmac]

As far as I know, there is no special battery made just for SUVs or RVs. They use the same batteries made for cars, trucks, boats, etc.

For an SUV or a boat to run lights and such what you need is called a deep cycle battery. This type of battery can be discharged more deeply without damage than a standard auto cranking battery.

If you need a battery for starting the engine you will do better to use a regular starting battery.

However if you can get these batteries for free then how can you go wrong? Even if it is a starting battery it will work fine for running boat lights and such. Probably won't last as long as a deep cycle battery but for free who cares if you get 4 years instead of 6.

[DeepFrz]

Golf cart batteries are probably the most cost effective. Marine batteries are usually not true deep cycle batteries. Only use a start battery for the engine start or windlass. Your house batteries should be deep cycle.

[Chef David]

Thanks all...appreciate the advice.

[NorthernSeaWolf]

You know what I love about Cruiser Forums? Everyone contributes information that my brain-housing group had yet to question!

Note to self...

Thanks!

[CrustyChief]

Just a recommendation, Nigel Calders "mechanical and electrical manual" it's one of those books everyone should have.