Dual Battery setup

You could battery box it up front, lots of ways to secure it underneath...straps, brackets, gla$$ in the box, cut and recess it at or in the "hump"... Im unfamiliar with the space and layout under the SNOB, so...? Just depends on how much time and energy you want to spend. Or you could volunteer your built in ice box for battery duty.
next you have at least 3 choices of perko switch, isolator, or combiner for connecting with the charging system.
I have also read that your batteries should be simaler in age, type and size, ie dont match a new gel or AGM battery with an older wet battery because the charge cycles differ.
You can also find tons of info on WakeWorld on this project.

I would like to use the second battery as a backup, but have it charging from the electrical system.

Or, have my stereo and amp wired to the second battery, and still have it get charged from the system.

Ice box is a good idea, since you have to flip the seat up to get to it anyway, so I usually use the icebox in the dash. I'll check out wake world as suggested to see what components I need to purchase.

Thanks for the tips.

todicus, I think the prefered/common way is your second choice above. Have one starting battery and the second for stereo/amp only, both will be charged by your existing alt.
How big of a sound system are you building?

I would just run them in paralelle. If you want you can put a switch on one of the cables, just make sure the amperage rating is good. Once you have the switch on you can put a diode in line around the switch so it will always keep one battery charged.



Tim

ok guys I have tried all 3 ways and find the easiest way way to use 2 new matching batteries with a continous duty solenoid.

Of course all you jeep owners know how the system works. For the boat what happens is if your sitting around listen to your stereo with your ignition key off when wired correctly the stereo and amps will play using 2 battery how does this happen the solenoid is in the open postion without power applied to it. The system works great when you start the boat your starting battery is full now solenoid closes and begins charging the batteries. Just my 2 cents

Why do you need a continous duty solenoid? just get an islorator from west marine and be done with it. Leave the radio and amp wired directly to the deep cycle bat and connect the isolator and charge both batteries from the alternator.

T,
So, right now you charge a freestanding batt before you go out and then just run the stereo off that? Wow, Interesting.
Isnt your ice chest hinged so you dont have to lift the seat to open it?
Was your single battery not enough to power your system?
I am currently running 2 amps, about 550 watts, 4 tower speakers, a sub and 4 boat speakers with one 5 year old $69. battery.
If you go two batteries, just use the isolator and you never have to touch anything again. Remember "79 is right"

    They do make a box they use in motorhomes(my Dad has one) where it is a delay timer to go to your continuous duty solenoid. I dont know exactly where to buy one though. It senses battery voltage as well as ignition key position. It bridges the batteries after 30 seconds of running if the main battery voltage reaches 13.8 or so. The disadvantage is the continuous duty solenoids (look and wire identically as a starter solenoid) fail every so often. A isolator is diodes which really never fail unless overloaded. One advantage of the solenoid is you can easily hook up a switch as a "battery bridge" in case your main battery goes dead for whatever reason, it would get you going. As far as getting "hot" the solenoid will get just as warm as the isolator. The bigger the isolator, the cooler it will run. Use the next higher rating to be safe.

                                    Jeff...

Darrel,

I just recently purchased the boat, and the previous owner installed the stereo and amp, but did not wire it to any switch........... it is hot wired to the battery, thus draining it until it is dead. So I would have to disconnect the leads everytime I docked the boat. So the second battery was a temporary fix until I had time to rewire everything (too busy skiing), and thought that a dual battery setup would be the way to go ( safety factor ).

On my 95snob, the ice box lid is covered by the seat frame, including half of the hinged portion.

So basically it is a mickey mouse setup, and I want to do it right.

And boy do I know that "79nautique is right". I'm glad he is alway's there to help.

just becaue the radio is wired directly to the battery means nothing I have mine that way. Now if you leave the radio on thats a problem turn it off and there's not an issue.

the amp won't come on unless the head unit is on. As far as the demo mode I would think that you can change the setting on the radio so that didn't happen and would turn off and not go into demo mode.

ya just a tad bit.   make sure that the sense(lack of better term) wire for the amp is hooked up to the lead from the headunit, if it is then the amp won't come on unless the headunit is on. Also look into that demo mode surely there has to be a way of disabling it. A way to test it to make sure that the unit is off is run a test light in series with the neg battery cable and if it comes on then there is a drain/headunit is on and drawing power. I don't use the clock function on mine as well, that is a slight drain as well so if that is hooked up directly to the battery then just remove the fuse to that line, it should be seperate from the main fuse for the headunit, while testing for a drain with the test light.

Ok, I'm gonna confuse ya even more. I run a solenoid to connect the batteries, but use a switch at the dash to decide when I want to connect or diconnect them. (Although the batteries cannot connect when the boat is off) A little flexiblity. Easier in my opinion than a Perko. (Forgive the drawing but CAD is at the office)



The parts:
Soloenoid (200 amp)
Relay
Relay Base
The switch is a small LED switch found at an automotive store. Fuse is to protect the switch.

The batteries should be identical. I ran a 200 amp breaker between the batteries (before the solenoid) and another between the battery and amps so I could easily disconnect the power from the stereo.
Don't skimp on the gauge of wire or connectors. I know it's expensive but will cause less problems down the road. Anyway with this setup, I can kill my stereo batteries while anchored and still start the boat. Hope this helps, and forgive the crayon drawing...

For the box, the 210 needs bow weight and I made my own box and covered it with resin. Worked out pretty well.

On my 79 I used a dash fuse location and put in a duck bill single pole switch and wired my stereo into it so that I can shut it off or turn it on without having the ignition key on. I then run it off the main battery and have had no problems with LOTS of power draw. You'd have to play the stereo for a long time to drain the battery enough to not start the engine.
The PO had it wired to the ignition switch and told me that he seemed to have a problem with burning out coils. Nothing worse than having the ignition sitting on and not running the engine...

I have used battery switches for a long time (35.00) and they work great. Requires some additional wiring work but the outcome is great if you just make sure and switch back and forth every now and then to charge everything up. The nice thing about a battery switch (Perko) is they very, very, rarely go bad yet I have had isolators burn out on me in my motorhomes. You can also turn the swoitch off when in storage and there will be no drawdown on your batteries from "hidden" power sources i.e. clocks.