DIY-Adding second battery

[cramer]

I didn't find much info on adding a second house battery for a larger stereo, so i thought this post may help some people.

To start, the factory battery is a size 24 and doesn't have much capacity for floating and listening to the system. A second battery (or battery bank) allows the start battery to be isolated and not be drained by the amps and offers the ability to still get home even if you drain the second battery. I went with a size 31 AGM for the second house battery.

I like the Blue sea Systems add a battery kit i used in a previous boat, so decided to use it again with a couple changes.
https://www.bluesea.com/products/765...ery_Kit_-_120A
The kit consists of 2 parts, the dual battery switch, and SI ACR that controls charging.

I followed this diagram for the most part, borrowed from the net:

MoombaStereoWiringR29-05-12.jpg

I did not place fuses between the ACR since I'm not concerned about a possible short on the short 4ga wires. Also, i only connected the ground wire for the ACR since i do not need the monitor led or starter cut out.

Here is the starting point on our '19 R22

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Pulling of the engine access panel and unscrewing the rear panel, you'll find the stock switch and single battery

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Working on the bench, i removed the battery switch and enlarged the hole for the blue sea systems dual battery switch. ACR got mounted below the switch. Then i moved over the power plug so i could install the battery charger plug on the starboard side along with mounting the dual bank 20 amp charger from Powermania

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Back in the boat, i moved over the starting battery tray to allow room for the second battery. The start 24 tray will hang off the edge about an inch for enough room to fit the house 31 size. Here is the test fit for the trays and two batteries:
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Then moving on to wiring up the new battery switch, keeping everything on the starting battery and 1 side of the switch that was originally wired, minus the 4 ga yellow and red wires from the factory amp. Connect the amp red power wires to the 2 position of the battery switch and the ground on the house 31 battery. I added a 2 ga ground wire between the two batteries instead of using a seperate ground bar.

The charger also gets connected to each battery and the ACR ground wire to the start battery with a 2amp fuse (smallest i could find in the mini size)

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Then put it all back together, making sure to reconnect the light and power port. Shown here with the charger plugged in testing connections.

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The charger is accessed by opening the battery door

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[Brianrzr]

Looks great! I’ve been thinking of doing the same thing.

[KoolAid]

stereo diagram.png
If you want to isolate engine you will have to make this wiring change. This will keep house from pulling from cranking. Your stereo and house can share and be on bank.

[chpthril]

Good catch Koolaid! He will have loads drawing from both banks while at anchor as it stands.

Also, I hate how that artist poorly labeled the batteries. "house" and "stereo" are redundant. "stereo" IS a house load.

Sadly, incorrect info, such as this schematic, get on the web, and stays there.

[BrentP]

Question though. That change you made will push the main dash panel/helm bus onto the house bank. So the starter is on its own battery, but all the electronics are not? Or does the engine ECm, fuel pump, etc all connect to the starter?

I actually kept my main helm bus on the starter battery for this reason. The major down side is all my ballast pumps run off that battery (since they are factory wired into the helm bus). I figure in the grand scheme of things, if one of those gets left on i probably have enough juice in the house batteries to combine and jump the motor. Long term I’d have to basically install a second helm bus for “house” loads, and keep the existing one for critical operation electronics right?


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[KoolAid]

Question though. That change you made will push the main dash panel/helm bus onto the house bank. So the starter is on its own battery, but all the electronics are not? Or does the engine ECm, fuel pump, etc all connect to the starter?

I actually kept my main helm bus on the starter battery for this reason. The major down side is all my ballast pumps run off that battery (since they are factory wired into the helm bus). I figure in the grand scheme of things, if one of those gets left on i probably have enough juice in the house batteries to combine and jump the motor. Long term I’d have to basically install a second helm bus for “house” loads, and keep the existing one for critical operation electronics right?


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That change you made will push the main dash panel/helm bus onto the house bank. So the starter is on its own battery, but all the electronics are not? - Exactly. This is what you want it to be. That way you always have a charged engine battery. The ECM, fuel pump (the engine fuse panel actually) gets power from the starter wire. The alternator feeds power to the starter wire as well.

How you set up your boat isn't the ideal method. You never want to pull power from cranking battery unless you are cranking. If you have house items on the cranking battery, the isolator can go haywire switching back and forth trying to keep cranking topped off or it will never see full charge on the cranking battery which causes it to never charge the house battery. See 2015-2016 boats with the pro mariner and incorrect wiring from starter to alternator.

[sandm]

See 2015-2016 boats with the pro mariner and incorrect wiring from starter to alternator.

wait...
I have a'14 with the factory promariner. is this something I need to look for? I doubt my boat has spent much time at a dealer over the years on recalls and such.

[KoolAid]

'14 didn't have the issue. The early raptors did. The alternator wire was cut at the factory and a new wire was ran directly to the promariner which caused the engine to always pull from cranking battery which would make it fall below the threshold of 12.3v (IIRC).

[cramer]

Thanks for the input KoolAid. I followed the Blue Sea System diagram that had the "start" side keeping all electronics, but had accessories on the house side. I wasn't sure where the ECM draws power from and wanted to keep it on the start battery.

The other item i need to find out is how the Touch 2 monitors voltage. It has dual readings for start and house, both currently have the identical reading, I assume from the same source.

[chpthril]

both currently have the identical reading, I assume from the same source.

This is part of what Koolaid has pointed out. In your original schematic, the helm and (which should draw from the house) is connected to the main cranking. So yes, they would "see" the same battery voltage.

[cramer]

This is part of what Koolaid has pointed out. In your original schematic, the helm and (which should draw from the house) is connected to the main cranking. So yes, they would "see" the same battery voltage.

Perfect, I was hoping that would solve the issue.

[KoolAid]

Cranking voltage on the screen is from the ECM through CAN. House voltage is what the screen itself is seeing. Mike answered the rest :-)