I have a 250 HO. When I bought the boat it had 4 AGM's of the same size in it (group 31). I need to replace. Is there any reason I can not use the Group 31 AGM from SAM's (duracel) for my starting battery? It also has all my electronics hooked to it. I would have 3 others for the TM of the same size.
I have heard from a couple people they are now running 5 batteries - is this becoming common? If so how are you fitting 5 into a Ranger Z520?
My 2014 Z520C had a group 31 Duracell AGM for cranking and it did fine. It is still possible to run down a group 31 battery if you have big electronics and run them all day plus running livewells all day, also failing to run the big motor enough throughout the day to boost th charge. But I never had that setup fail to start my gas motor after a full day’s fishing, and if needed, I always had the jump start switch to fall back on.
If you have 4 big batteries, an external oil tank, and dual power pole pumps, the only way to squeeze in a 5th battery would be to wire it into a rear storage compartment. If you have no power pole pumps, the 5th battery can sit on the prop storage board, in front of the onboard charger. I’d hate to have another 80 pound battery in the rear, plus all that other stuff, because of how it would affect boat performance....
John Clark — Findlay, Ohio
Is there a better battery to use on the starter than a 31 AGM that is also running the rest of the electronics? I can get these for $159 per until the 25th of March.
If it's 1000 or more cranking amps and 200 or more minutes of reserve run time then I think it will be okay. On the motor I would not want less than 1000 cranking amps because I am pretty sure Evinrude recommends at least 900. As for reserve if you run a lot of accessories then you need a high reserve so the battery has power when it comes time to crank. Anything less than 200 would be weak IF you're running a lot of accessories. People often get caught up in group size and overlook the specifications which are more important that group size in my opinion. Group size is only a reference to the physical size of the battery. You can get a group 31 that has less amps and reserve than a group 29 but the number 31 is larger than 29...pay attention to the specs.
Specifications
1 amp hour rate:68.2
100 amp hour rate:110
20 amp hour rate:105
3 amp hour rate:85
5 amp hour rate:86
6 amp hour rate:87.4
8 amp hour rate:90
Battery Electrolyte Composition:Glass Mat
Battery End Type:Top Post
Battery Purpose:Starting Lighting Instrumentation
BCI Group Size:31
CCA at 0 degrees F:800
Freight Class:65
MCA at 32 degrees F:1000
Minutes at 15 amps:348
Minutes at 25 amps:210
Minutes at 5 amps:1265
Minutes at 50 amps:87.4
Minutes at 75 amps:53
Minutes at 8 amps:706
Polarity:Left Positive
Reserve Capacity:200
Terminal Type:STUD/SAE
Volts:12
It’s nearly impossible to get overkill capacity in a cranking battery these days. The specs you post above look fine and should perform admirably for you. The big wild card in the equation is electronics on the boat. If you run anything from 2 to 4 big mapping units, it is possible to pull down any single cranking battery. But it’s also possible to avoid pulling it down (below starting power for your engine) with careful battery management. Just be thankful for the engine you have. It starts easier than most of the competition.
John Clark — Findlay, Ohio
I think JR19 hit it on the head. As long as the CCA/MCA rating is larger than that of the requirements for the motor and it has a high enough reserve capacity, you’re set.
The RC is what you care about for the units. The larger the RC number, the longer you’ll have running the units, pumps and anything else you’ll have on in the boat.
I have a helix 10, and a 997c on the boat with a 360. Other than that it is live wells and occasionally the stereo.
Very well saidOriginally Posted by jc2bg
Stopped in to Batteries plus today - they too sell the duracel but at a premium compared to Sams. The sales guy then tried to push me to the X2 which looks like a very powerful battery but is it worth the $300 each to go from 1000MCA to 1150 and 200 to 225 reserve capacity? I have 10 year old AGM's in there now and although they still work you can feel it after a long day on the water and if I am in heavy current on the river it is pretty challenging to make a full day.
Duracel AGM 31 at sams - $159
Duracel AGM 31 at BattPlus - $215
X2Power at BP - $318
Sams
All Batteries out - heading there today. Looking at the specs of the old ones they were Deka AGM g31 with nearly identical specs as these duracels. Found the stamp on them.. they were put in service Aug 08 - 10 years not bad lets hope I get at least half that out of the next set.
Thanks for everyone's input I am sure these new ones will perform better than the aged ones.
Wow 10 years...I just switched to a AGM for cranking two years ago. In fact I switched to a Deka 31 8A31DTM. In the past I would change my regular cranking battery every 3-4 years whether it needed it or not. I have heard AGM's have more life so hopefully I can go beyond 5 years with confidence.
Reply With Quote
