New cranking starting battery with helix 9s

[Jdwelding]

I'm replacing my batteries this year on my Champion.
Also going from gen1 HDS 5s to a pair of bird helix 9s.
My motor is a 95 200 xri.
After researching, seems I should go with a group 31.
I will wire the birds direct to the battery with 12 ga. I was thinking of the Duracell dual purpose group 31.
Will this have enough CCA and MCC for my motor and accessories? I don't have any power poles. Just pumps, lights and a USB charger.

https://www.batteriesplus.com/batter...p-31m/sli31mdp

[CatFan]

If you listen to Mercury’s recommendations, you can’t use a dual-purpose, deep-cycle or an AGM at all.

I think it will work fine.

[Jdwelding]

If you listen to Mercury’s recommendations, you can’t use a dual-purpose, deep-cycle or an AGM at all.

I think it will work fine.

That's one of the things that has me confused. These new graphs do put a drain on the battery. I sure don't want to be stuck on the water. Batteries will be hooked to a noco 3 bank after every outing

[Jonestrollingmotor]

I would consider going from a lead/acid that you're looking at to the 31 series AGM. Sams sells one marketed under the Duracell name that works well.
John

[Jdwelding]

I would consider going from a lead/acid that you're looking at to the 31 series AGM. Sams sells one marketed under the Duracell name that works well.
John

Mercury says no AGM

[CatFan]

Mercury says no AGM

If you want to follow Mercury’s guidance, get a group 24 cranking battery. If you want to fish, get the one you or looking at or the one John recommended from Sam’s.

[coreynov902]

Not trying to hijack the thread, but I'm also looking to get a new starting battery. My motor is a '99 Merc and I have also heard I should not get an AGM or a dual-purpose battery. Can someone explain why you are not supposed to use one of those batteries types with those particular motors? I'd like to get a dual-purpose but haven't yet because I don't want to mess up my motor.

[DQM]

I believe that motor uses a stator charging system, not an alternator. Yup, it does I just looked it up.

Because it uses a stator system, that is why Mercury says not to use an AGM battery and I would agree. Stick with a standard wet cell starting battery.

Stator systems don't regulate higher voltages as cleanly, and thus can burn out AGM batteries prematurely, especially with older regulators and rectifiers. But even more of an issue, an AGM battery or even a deep cycle wet cell can pull a lot more current off of the stator when they are deeply discharged thus damaging your regulator and possibly rectifier as well.

[CatFan]

Stator has nothing to do with regulation. That is the regulator. The reason Mercury recommends against the larger batteries and AGMs is that they are trying to limit the heat load on the regulator because the stator has relatively low output current. They are mistaken. The load on the regulators is because of the electrical load from all the accessories, not the battery technology or RC. Mercury’s position is like saying a smaller gas tank on your truck will save money on gas.

Use whatever battery works for you. Keep an eye on the regulators for signs of wiring overheating. Or trade your outboard for a new one.

[DustyD26]

Interstate 27M XHD

[CatFan]

Interstate 27M XHD

What is different about that battery (which is a very good one) and a dual-purpose or deep-cycle? That is the problem with Mercury’s recommendation. There are batteries that aren’t marketed as deep-cycle that have the same specs as deep-cycles. Outboard doesn’t care what the label says.

[Jonestrollingmotor]

The stator type charging system is not different than an alternator. Still produces AC current that is converted to DC through the rectifier. It's done by magnets in the flywheel passing through a series of "charge" bobbins creating the AC electricity. The alternator uses an energized rotor (that becomes an electromagnet) spinning inside a stator to produce AC electricity. Difference is the limited amp output of the stator system vs the higher amp output of an alternator, however, unless there is a load on the battery that is pulling excessively, the charging system will not see the max output. When it does, it tends to burn components. Both are regulated to charge on demand (battery conditions determine the demand) to keep the battery maintained or charged. Both will work with the AGM.
John