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View Full Version : Wow... Another Add A Battery Thread Question


Lakeside09
04-20-2012, 09:20 AM
Ok so I added another battery to my audio set up. I'm using the Promariner Prosport 12 for my onboard charger... found out i had a bad starter battery so i moved my deep cycle interstate battery to my starter... charged my old starter and was going to try it as a house battery just to see how bad it was... lasted about 2 hrs on the water.

I am going to buy another deep cycle interstate battery for my amps and i may go with a little bit bigger one. Id like to make it a little more efficient so do i need to wires those batteries parrallel? Although, I dont want to put that big of a strain on my alternator. Im also thinking about installing a ACR.... but i dont want to mess with switches or anything... just go out blast all day... come home stick it on the onboard charger and be ready for the next day.

I'm running my house battery to my Polk PA880 amp with 10" Polk MM Sub and one 1000 watt Exile Harpoon Amp to my 4 XM9 tower speakers.

93ProStar205
04-20-2012, 11:21 AM
If you plan to run parallel at all, get identical batteries both in good condition. Otherwise one discharges into the other. I have two identical cranking batteries, but once accidentally got flattened a few months ago and it's dragging down the stronger one when I go to "both" on my switch.

JRW160
04-20-2012, 11:32 AM
If you want to wire them in parallel, they need to be the same type and age. Another problem running them in parallel is that if you go out and blast all day, you will eventually end up with 2 dead batteries and no way to start the boat without jumping it off. It also may put too much strain on your alternator. You need some way to separate the batteries (switch, isolator, etc)

I have 3 batteries in my boat. 2 wired in parallel for the stereo and a starting battery. The amps are hooked up to the stereo batteries and everything else in the boat hooks up to the switch. It makes it easy, and I never have to mess with the switch unless the starting battery dies for some reason. A friend of mine is running the same setup, but he has a hellroaring isolator between his house and starting batteries instead of a switch.

Lakeside09
04-20-2012, 11:52 AM
Iv e ran that interstate as my house battery not connected to anything just my amps and the onboard charger... it lasted all day with no problems... do you think it would be ok to buy a new bigger battery keep it seperate and just fully charge it before heading to the lake each time?

Thrall
04-20-2012, 12:05 PM
I wouldn't parallel them. If you have one house battery just running the stereo and the other as a start battery, only running the normal boat functions, you shouldn't ever need the extra juice to start, but on the odd occasion if the start battery goes down you can always swap batteries to get going.
I'd hook your house battery into the boats charging system with an ACR and you won't need to do anything other than have a simple disconnect (like the ground wire for the ACR) switch to properly charge with the onboard charger hooked to each battery.

Lakeside09
04-20-2012, 12:24 PM
Can you please explain more about hooking the house battery and acr to the boats charging system? And how to do that?

JRW160
04-20-2012, 01:28 PM
Iv e ran that interstate as my house battery not connected to anything just my amps and the onboard charger... it lasted all day with no problems... do you think it would be ok to buy a new bigger battery keep it seperate and just fully charge it before heading to the lake each time?
You should be fine running a larger battery separate and just charging it every night, but you may want to consider adding 2. I run 2 115ah batteries for my stereo, and I've managed to drain them a couple of times.

Jeff d
04-20-2012, 01:33 PM
If you throw a Blue Seas ACR in front of you deep cycle house battery then the only time the house battery would receiver a charge from the alternator/cranking battery would be when the alternator has been providing 13+ volts for 2 minutes.

So, the heavy starting leads would go to your cranking battery. The lighter gauge "house" leads and leads for your amps would go to your deep cycle battery. Then the ACR would go between the positive posts of both batteries. When the engine is off then the ACR would be open or "off" so you wouldn't be able to drain the cranking battery with your stereo or other accessories. Starting power will then only come from the cranking battery but after the engine has been running for 2 minutes it will start charging the house battery too.

If your deep cycle house battery was severely depleted to below 10.8 volts then it won't combine them to avoid draining/damaging your cranking battery.

I plan to go that route shortly.

jafo9
04-20-2012, 05:32 PM
i'm a big fan of the Blue Seas "Add-a-Battery" system. I installed it in my pontoon which has a 12v fridge onboard that runs basically all the time. We'll park the boat all day and run radio/fridge and never have to worry about getting back home. 13.6v is the magic number (iirc) that it kicks in and ties in the house battery to get charged. In other words, when the crank battery is "full" it spills the charge over to the house battery. In my experience, since you are ONLY asking the crank to actually crank the motor, it only takes a few minutes before you see the ACR combine the 2 batteries. I added a second independent voltmeter on my helm in the pontoon and you can watch the voltage change on the house battery when the ACR kicks in. The initial wiring can be a bit of a hassle, particularly if you wire in all the correct fuses and the starter isolator switch per the Blue Seas instructions. I also wired in a dual bank charger with an extra switch to kill the isolator so the batteries get "floated" independently. The initial wiring was a hassle, but now it truly is unplug and play. It really is a no brainer for the wife and guests.

On my X30, I opted to go with the old fashioned 1,2,1+2,off switch for my dual battery setup. Our radio setup isn't that fancy and my guess is that this summer if we are going to go just "float" for hours we'll probably still take the pontoon (this will be our first summer with the X30). The old fashioned switch is much easier and cheaper to wire, but it does require user input by actually using the switch and training others to use it.

Jeff d
04-20-2012, 07:43 PM
I like the idea of both a manual selector and the ACR but that's a lot of extra wiring. I think I'd rather have one or the other. It seems like somebody would make one box that's both an isolator, charging relay and manual selector all in one. With what's currently available I think I'd rather just have the ACR and manually move the cables around in the off chance that I needed to crank with the house battery.

Lakeside09
04-20-2012, 09:51 PM
If you throw a Blue Seas ACR in front of you deep cycle house battery then the only time the house battery would receiver a charge from the alternator/cranking battery would be when the alternator has been providing 13+ volts for 2 minutes.

So, the heavy starting leads would go to your cranking battery. The lighter gauge "house" leads and leads for your amps would go to your deep cycle battery. Then the ACR would go between the positive posts of both batteries. When the engine is off then the ACR would be open or "off" so you wouldn't be able to drain the cranking battery with your stereo or other accessories. Starting power will then only come from the cranking battery but after the engine has been running for 2 minutes it will start charging the house battery too.

If your deep cycle house battery was severely depleted to below 10.8 volts then it won't combine them to avoid draining/damaging your cranking battery.

I plan to go that route shortly.

I really like this idea... I will probably go this way.