I need new Batteries for my 228

[seasick]

I am right in the middle of a complete redo of my 96 Islander, it had a single 300 hp and I upped it to twin 175s, So I needed to up the battery power, after checking out a variety of options I decided I wanted AGM batteries, of course they are the most expensive, I was already shoveling cash at this , so I figured what the hay, I did manage to save some, quite a lot, by buying at a local O’Reillys auto parts 3 Marine/ RV group 34 AGM ‘s for $519
at most any other it would be $900- $1200
Granted they may not last 10 years , but 3-5 years is fine with me

I am not sure it is always necessary to up the power as you say when switching from a single to twins. I would assume ( I may be wrong) that the 300 draws more starting current than the 175. If that is so, as long as you start one motor at a time, the original battery sizing should be sufficient. Perhaps I am missing something. I guess it depends on how many batteries you originally had, what type they were , and what was wired to what.

 

[Hookup1]

This won't help you now but maybe someone else...

Sam's Club Duracell Group 34M $124.88 as of today. It was worth the price of membership to get my Duracell AGM's.

Duracell AGM Deep Cycle Marine and RV Battery, Group Size 34M - Sam's Club

Buy Duracell AGM Deep Cycle Marine and RV Battery, Group Size 34M : Marine Batteries at SamsClub.com

www.samsclub.com

 

[seasick]

Some model engines like the Optis on one of my boats specifically states in the manual that only starting batteries are to be used for the engines. I can attest to the fact that those Mercs are very particular about battery voltage and if that is just a tad low, the motors will crank 'normally' but the motor will not fire up. There is some sort of circuitry in the PCM that turns off the ignition if the voltage is not at or above a particular level.

The Optis, even the smaller ones, draw more starting amps than a lot of other model motors and the voltage/current characteristics of the battery are picky

 

[Ryhlick]

So I ended up getting a pair of these batteries, I hope they work out.​

Specifications​

• Part Number24M-AGM-A
• Group Size24
• Cold Cranking Amps (CCA)750
• Cranking Amps (CA)937
• Reserve Capacity (RC)140 minutes
• Amp Hours (Ah)70
• Length10 1/4 inches

• Width6 13/16 inches
• Height8 7/8 inches
• Termination CodeMARINE TYPE POST
• Voltage12
• Wet/DryD
• TechnologyAGM
• 

 

[Hookup1]

Some model engines like the Optis on one of my boats specifically states in the manual that only starting batteries are to be used for the engines. I can attest to the fact that those Mercs are very particular about battery voltage and if that is just a tad low, the motors will crank 'normally' but the motor will not fire up. There is some sort of circuitry in the PCM that turns off the ignition if the voltage is not at or above a particular level.

The Optis, even the smaller ones, draw more starting amps than a lot of other model motors and the voltage/current characteristics of the battery are picky

The trick for the Manufacturers is to "make your own power" inside the computers. Most electronics will do just that. Where you see a Garmin unit that will run on 10 VDC to 32 VDC that is what is happening. The newer autos are no different. They need lots of power to run the computers and the fuel injection.

 

[seasick]

I agree with your statement in general but the PCM for the earlier Optis isn't that 'smart' The PCM is running fine but it's software disables the ignition system if voltage is slightly low which is not that hard to do on my boat for a few reasons: These engines have both fuel and air injectors. The system draws a lot of current when starting especially a cold start.
The point I was trying to make is that Mercury specifically states not to use anything other than a starting battery of 1000 MCA and 800CCA.

 

[blindmullet]

I agree with your statement in general but the PCM for the earlier Optis isn't that 'smart' The PCM is running fine but it's software disables the ignition system if voltage is slightly low which is not that hard to do on my boat for a few reasons: These engines have both fuel and air injectors. The system draws a lot of current when starting especially a cold start.
The point I was trying to make is that Mercury specifically states not to use anything other than a starting battery of 1000 MCA and 800CCA.

Optics also draw voltage differently when running. If I remember correctly at idle the voltage draw is slightly more than the charge. Weak or incorrect batteries on an Opti will have you chasing ghosts...... unfortunately I have seen that ghost. Lol

 

[seasick]

Optics also draw voltage differently when running. If I remember correctly at idle the voltage draw is slightly more than the charge. Weak or incorrect batteries on an Opti will have you chasing ghosts...... unfortunately I have seen that ghost. Lol

Everything voltage related is quite different than the Yami motors. There are both ghosts and daemons in those Optis

 

[PNW_Drifter]

User error is what usually murders batteries. Take the user out of the equation and buy an ACR.

 

[Surely Bassey]

I have a pair of Interstate Group 24 going on the 4th season and they both measure good.
I will say that even 2 group 24 adds a bunch of weight to the back of my 228.

 

[Mustang65fbk]

I'm late to the party here but I typically always get my batteries from Costco, unless it's a special type of battery that they don't offer, as they generally have a 36 month warranty or return policy on them. On top of that, Costco has a fantastic return or exchange policy to begin with, so I almost always buy something from them if I can in the event that I do have an issue, that it can be returned or exchanged. The only battery I haven't bought from them was the Optima red top battery that I bought for my 1965 mustang fastback, and that was only because Costco didn't offer them, or at least didn't at the time.

https://www.costco.com/interstate-27dc-marine--rv-battery.product.100476408.html

 

[trapper]

I bought two energizer AGM group 31 dual purpose batteries from Costco a coupe of months ago but have only had the boat out once. I think for my needs, running down riggers pulling traps and overnight boat camping they should be fine.

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Item # 140731