Recommended batteries/group #'s

S

susanandlance

Well-Known Member
Feb 10, 2011
2,865
Florida
Boat Info
2007 Sea Ray 36 Sedan Bridge
Engines
8.1 mercruisers
What are you guys running? 2007 Searay 36 DB, boat isn't here yet and wanted to see what fits and recommended
 
I also went from Group 27 wets to Group 31 AGM's in my 98 290 DA.

My boat stays in the water 365 hooked to shore power on a ProNautic charger when I'm not afloat.

If you change to AGM just make sure your charger is good to go with the change.
 
I never had an issue with 27's in my 340. I could go 2 nights on the hook with everything running and still have juice to get started on that third morning. During the summers I was struggling with my generator I got to know my batteries quite intimately. :)

If you've got (and use) a generator it's almost a moot point...IMO.
 
I have been boating with wet M27's my whole life. In my case to go bigger or go to AGM's would be a waste of money. Just never sit on battery only for any substantial amount of time to justify the change
 
Thanks for the info, this boat has side by sides in the galley and icemaker on cockpit
 
I wonder what kind of modification if any to mounting platform to go from group 27 to 31's? Been awhile since I did that upgrade to a previous boat
 
Blueone said:
I have been boating with wet M27's my whole life. In my case to go bigger or go to AGM's would be a waste of money. Just never sit on battery only for any substantial amount of time to justify the change
Click to expand...

While I agree with the sentiment expressed here, I always opt for increased reserve battery power if an option.

MM
 
susanandlance said:
I wonder what kind of modification if any to mounting platform to go from group 27 to 31's? Been awhile since I did that upgrade to a previous boat
Click to expand...
It depends what you have now. I have trays with metal hooks and a bar that goes across. 31's will not fit in a 27 tray. So I would need new trays...that's about it. See what you have ..your tie down system might fit 31's
 
MonacoMike said:
While I agree with the sentiment expressed here, I always opt for increased reserve battery power if an option.
MM
Click to expand...
You can say that about everything...fuel water etc... but if you don't need it..you don't need it. I have seen 31's go to hell just as I have seen 27's... I think dealers choice in this one
 
Will find out next week when she arrives, thanks guys!! If 27's will power everything for 24 hrs and start engines after that I might stay with 27's, down here you have to run genny every night anyway, too damn HOT!! 85 degrees today......lol
 
Blueone said:
You can say that about everything...fuel water etc... but if you don't need it..you don't need it. I have seen 31's go to hell just as I have seen 27's... I think dealers choice in this one
Click to expand...

There is a significant difference in 27 vs 31 in the Optima line. 100 CCA, and 9 Ah per battery. This is worth the difference to me. The negative is added weight as the 31 has so much more meat to it it weighs 6 pounds more per battery, but that weight provides more margin before running it down or flat in a situation.

MM
 
M Prod said:
Boohoo ..cry me a river. ;-)

I've got trays made specifically for the group 31's with a bracket that holds them in. The trays are screwed down into the fibreglass.

Similar to these: https://www.amazon.ca/Plastic-Batte...ocphy=1001931&hvtargid=pla-571017717505&psc=1
Click to expand...
I think I've actually got a set of 3 like these that I've not been able to get rid of (I'd have to check which battery family they are for actually before committing to 27s or 31s). If anyone is interested I'm happy to ship them out, would only ask for shipping costs to be covered. I say I think I still have them because the wife may have tossed them out during our latest bout of spring cleaning, I can check tonight.

Anyone PM me if you are interested.
 
One point not often mentioned in these threads is that even though a certain size battery may handle your loads, upgrading to higher capacity will decrease the total draw-down for a given load and timeframe. Drawing wet cells below 50% of their capacity will seriously shorten their life (~80% for AGMs)

So even though you may be able to run your battery to within an inch of its life, it's not a good idea. Thats where additional reserve capacity comes in handy. I usually get the biggest baddest AGM that will physically fit.
 
You must log in or register to reply here.

Forum statistics

Threads
113,172
Messages
1,427,835
Members
61,084
Latest member
AntonioJamm
Back
Top