Group 31 Batteries in a Seafarer 228?

[Seafarer_Bob]

I'm replacing my batteries and that space under the aft seat looks like a tight fit so wondering if anyone has put 2x 31's in the same compartment? My T9 kicker is on the opposite side so need them both on the port side for balance.

I first started researching the Blue Sea ACR, add a battery combo with one smaller dedicated starting battery facing front to back + one group 31 house facing side to side but I was strongly advised against mixing different batteries with that device since it combines them while charging. I've used the Yamaha battery isolator cable for that application but not sure I want to deal with snaking and reworking all that cabling etc.

I know I can fit 2 x dual purpose group 27 AGM's and just use my existing boxes, switch, and wiring, etc Dior an easy solution but figured I'd get some input here before going that route.

Optima Blue top with light grey bottoms in case that matters.

 

[DennisG01]

Take some cardboard and make a "battery" based on the manufacturers dimensions. Heck of a lot easier than trying it with real batteries.

 

[Ky Grady]

I've got two 27's in my port box for trolling motor. 31's would be tight. The battery tray pic is before I had put all the hoses back in. Got small once those went in.

 

[davescarp]

I'm replacing my batteries and that space under the aft seat looks like a tight fit so wondering if anyone has put 2x 31's in the same compartment? My T9 kicker is on the opposite side so need them both on the port side for balance.

I first started researching the Blue Sea ACR, add a battery combo with one smaller dedicated starting battery facing front to back + one group 31 house facing side to side but I was strongly advised against mixing different batteries with that device since it combines them while charging. I've used the Yamaha battery isolator cable for that application but not sure I want to deal with snaking and reworking all that cabling etc.

I know I can fit 2 x dual purpose group 27 AGM's and just use my existing boxes, switch, and wiring, etc Dior an easy solution but figured I'd get some input here before going that route.

Optima Blue top with light grey bottoms in case that matters.

What's the problem you are trying to overcome here? Are dual 27's not enough juice? Did Bluesea's advise you against using their ACR with different size batteries? If you aren't using an ACR or AUX charging cable from the motor, how are you keeping your house battery charged currently?

 

[Seafarer_Bob]

Group 27's will probably be enough but I'd rather not have manually work the A/B switch like I do now. I like the idea of a dedicated high cranking starting battery and extended run time of a group 31 for house with no switching. The group 31 optima blue is very high cranking but seems excessive to have two of them if i can only use one of them for starting. I may make the cardboard boxes and see if the 31's fit, only a few more pounds and $ over the G27's ....

The tech at Blue Sea said "no problem, people do it all the time" but the tech at Optima said "it's not advisable to even to combine dissimilar batteries temporarily even to jump one to the other in an emergency". After all the issues I hear people have with batteries I'm leary to go against the MFG recommendation.

My brother's Regulator has dedicated starting batteries and the group 31 house battery is only connected to the motors via the Yamaha isolator cable (MAR-69JIS-Ol-ED) which plugs directly in the voltage regulator on the engine so house and starting batteries can't be combined unless you use jumpers. Last summer I left something on in the regulator which drained house to zero. No switches or anything, just started the engines and went on my way, simple.

 

[SkunkBoat]

You should always have a House switch or switchable breaker. Especially now with so many NMEA2k units drawing power even when they are turned off.
I use the Aux charging cables from the motors for House, keep Start and House separate and moved the switches under the gunnel so I did not have to open up the hatches and remove bins to turn switches. And I still have ability to switch to use the House to start in and emergency and use a start battery as House in an emergency.

take a look at New Battery Config for 265 for ideas

 

[SmokyMtnGrady]

in short I don't think 2 group 31s will fit. as it is the two group 27s are a tight fit.

 

[Seafarer_Bob]

I tried the box model like Dennis suggested but they wouldn't fit. But, Optima's are narrower at the bottom and the transom angle gives me some room so decided to give it a go and they fit snugly against the back of the back of the Cockpit bulkhead like they were made for it. I had already bought the fitted Optima boxes from T&H marine which are cool but after I finished the swap I realized the Optimas probably would have fit the standard boxes.

So upon taking this photo however I noticed the date code was 4/19 on one of the batteries and sure enough it barely turned over the main. I hooked it up to my charger and it only registered 40%. Called the dealer i bought them from (using my nice voice but) fully expecting a beef and he agreed to swap it out with a fresh one.

For now I'm just going to run it on my standard 1 / 2 / Both switch but looks like have room for another small dedicated starting battery in front of the washdown pump. If so I may install the Yamaha Isolator cable and I'll be good to go.