Multiple Boat Batterys?

[ccundiff12]

ok i know someone is going to inevitably tell me to search for this one, but i have and can't seem to find a great answer to this so here it goes....

i have an older 23' searay that is a pleasure boat on lake erie ohio. I have ADDED quite a bit of electronic equipment on board; computer (for gps mp3, dvd ect...) stereo, ship to shore, depth / fish finder, fans in the cabin, and a 1000watt inverter (blender ;-) ect...)

The boat has only one battery currently. I would like to have a "house" battery that is separate from the starting one. I do not have any electric at the dock to plug in an AC charger so the second battery would have to be charged by the engine (either the alternator, or a seperate dc-dc charging system) I will be sleeping some nights in the cabin so i would like to be able to use the lighting and fans without fear of killing my starting battery completely. is 2 batteries enough for what i want to do or is three going to be more suited for the task? any suggestions here would be very much appreciated.

 

[gstanton]

Re: Multiple Boat Batterys?

My 23' Sea Ray came with 2 batteries and a Perko switch to select among #1, All, #2, and Off. I can charge both while running in the "All" position, and then switch to 1 or 2 (or all) while at anchor. It looks like a relatively easy job to do.

I would think the extra battery would be enough for your needs, however the inverter might be tricky.

 

[ccundiff12]

Re: Multiple Boat Batterys?

i bought one of the perko switches last year, just never installed it, somewhere along the line someone told me that it was bad to put the selector switch on "both" when one battery is charged and the other isn't. so if i drain one by using it overnight but i want to charge it while the boat is running what is my best option? how long would it take to charge one of those batteries off of the alternator?

 

[Don S]

Re: Multiple Boat Batterys?

There are about as many different opinions on battery systems as there are on "What's the Best Oil for my boat" subject.
My suggestion would be to determine what you want and do some research on the possible ways of doing it.
Here is one resourse.
http://bluesea.com/resources/1

Be sure to look at the following sections:

AC SOURCE SELECTION AND POWER DISTRIBUTION
AUTOMATIC CHARGING RELAYS
BATTERY SWITCHING AND DC POWER DISTRIBUTION
INVERTERS
UPGRADING MARINE ELECTRICS

It will sure help you understand some of the possibilities out there.
There are also your basic 1/2/Both-OFF switches that allows a cheaper yet usable method of selecting batteries for starting and house systems. IF you use them properly and don't forget or get lazy and forget to change the switch when you should.