Hooking up another battery

(ndavis03) · (ndavis03) **Join Date: Jul 2006** 04-23-2008, 8:19 AM

I have the standard battery that came with my boat, but just realized I have an Optima yellow top laying around. I plan on installing a few amps in the near future, so it would be worth installing the Optima. What is the best way to hook the Optima up? I have plenty of room for it around the existing battery.

(malibuboarder75)

I have a perko 2 way battery switch. Basically when you drain one battery, you switch to the other to start the boat up. You can't run 2 batteries in series because it will kill the alternator.

(lovin_the_wake)

I use an isolator on mine and have never had a problem

(azpowerhouse) · (azpowerhouse) **Join Date: Jul 2007** 04-23-2008, 9:25 AM

My battery switch has 3 settings, battery 1, batt 2, and then both. I usually run it on both(50 hours of doing it) so this is bad for the alternator?

(05mobiuslsv) · (05mobiuslsv) **Join Date: Apr 2006** 04-23-2008, 9:37 AM

No it's not bad for it, it's just charging both when engine is running.

(ndavis03) · (ndavis03) **Join Date: Jul 2006** 04-23-2008, 9:41 AM

My stereo shop told me that on my last boat, the main battery was hooked up together with the Optima yellow top. However, there wasn't a perko switch. Were they in parallel or series?

(bcrider) · (bcrider) **Join Date: Apr 2006** 04-23-2008, 9:45 AM

Part of the problem with running batteries in series from what I understand is that the stronger battery will pull a charge from the 2nd battery so your not really charging both batteries. It needs to be on one or the other.

In my boat the first battery is starting only. The second battery is for the stereo.

I use a solenoid isolater. I orginally had a diod style and a Alternator repair dude said I shouldn't use that style due to the fact that they don't pass the current as well. The nice thing with the solenoid isolater is that it is triggered by the ignition.

Check out the link below.

http://www.piranhaoffroad.com.au/products/dualbattery/dualbatteryinfo_isolator.htm

(05mobiuslsv) · (05mobiuslsv) **Join Date: Apr 2006** 04-23-2008, 9:51 AM

Nick your batteries were in parallel.

(lovin_the_wake)

I ran 2 batteries in parallel in a car one time when I was big into stereo comps. and I fried the main computer and some of the electronics in the dash

(lovin_the_wake)

I'm using an isolator in my boat right now but if I was going to do it all over again I would definitely go with a perko switch

(05mobiuslsv) · (05mobiuslsv) **Join Date: Apr 2006** 04-23-2008, 10:03 AM

I doubt is was becuase of the 2 batteries. It would do nothing but supply a larger reserve of battery power. It might be a bigger strain on the alternator, but it wouldn't cause your computer to fry. Maybe you accidentally wired them in series.

(ndavis03) · (ndavis03) **Join Date: Jul 2006** 04-23-2008, 10:05 AM

This is all foreign to me, but how do you wire them in parallel?

(05mobiuslsv) · (05mobiuslsv) **Join Date: Apr 2006** 04-23-2008, 10:06 AM

All you do is hook the positive terminals together and the negative terminals together.

(ndavis03) · (ndavis03) **Join Date: Jul 2006** 04-23-2008, 10:08 AM

Thanks-thats what I thought, and thats what it looked like on my old boat.

(wakeshoe) · (wakeshoe) **Join Date: Jun 2004** 04-23-2008, 12:13 PM

Perko Switch, Battery Switch, isolator? What do these do and what are the pluses and minuses of each?

(trentj6930) · (trentj6930) **Join Date: Oct 2007** 04-23-2008, 12:24 PM

If any of the batteries were in series you would have 24 volts and not 12. Now that will cause you some major grief!

(lovin_the_wake)

hmmm maybe that's what I did - to + and + to - hell I was probably sauced when I did it too :-)

(lovin_the_wake)

either way I recommend using a perko switch they're more effective and a lot cheaper

(jay_g) · (jay_g) **Join Date: Apr 2006** 04-23-2008, 1:29 PM

anyone have a diagram on how the perko is hooked up with a stereo? im a lil confused on how they work

(malibuboarder75)

I have a perko switch for sale if you interested. I was going to use it on my boat, but never got around to it.

(brucemac) · (brucemac) **Join Date: Dec 2005** 04-23-2008, 1:45 PM

search around there's tons of info on this board.

on my old boat i had a perko switch and a yandina battery combiner. the combiner charges both batteries under power, but isolates battery 2 after battery 1 drops below a certain level. pretty cool. it's essentially foolproof. even if your alternator went out and you drained battery 1, you'd still have enough juice in battery 2 to get her home.

now i have to do it all over again. :-)

(billy2603) · (billy2603) **Join Date: Mar 2007** 04-23-2008, 2:22 PM

Crude drawing of back of Perko.

Hook positive of battery one to "1" and positive of battery two to "2". All stereo, starter, and accessory power to "3".

Hook negative of battery one to battery two and then to negative of starter. Also, all stereo and accessory can be grounded to either negative battery post as they are connected anyway.

Turn dial on front of Perko to "1" to draw from/charge battery one, "2" to draw from/charge battery two, "all" to draw from/charge both, and "off" to disconnect system completely.

If you want multiple batteries for stereo, then hook starter battery to "1" and then hook all positives from stereo batteries to "2" (all negatives can still be connected across all batteries)

(brucemac) · (brucemac) **Join Date: Dec 2005** 04-23-2008, 2:54 PM

also remember that if it has an "off" posistion not to switch to or past this while underway. it's not good for the alternator. :-)