Battery

[Interloper]

I am looking for recommendations regarding a starting battery. I have a 250 hp Mercury 2-stroke. The main starting battery is rated for 400 Marine Cranking Amps (MCA). It is clearly undersized. There is a second dual-purpose battery that is rated for 625 MCA. The Mercury website advises 630 MCA or 490 Cold Cranking Amps (CCA) for my motor. My outboard mechanic has recommended at least 750 MCA.

 

[DaleH]

Well I tell you, that starter's peak amperage is ~225 amps. I'm a fan of 'appropriately sized' dual-purpose batteries, there so much better for running and then drifting or anchoring with the electronics or stereo going. I'd guess that a Group 29 should be rated ~875 MCA and 675 CCA.

FWIW, in the last few years I've become a convert to the EverStart batteries sold by Walmart. Before you laugh ... the EverStart Marine batteries are made by Johnson Controls. And to top ot off, those Optima gel batteries are also a Johnson Controls company. If you comparison shop, you'll find the WW battery has a highest reserve amps, CCA, and MCA numbers when compared to batteries by West Marine, Sears, Bass Pro, or Exide. And, they'll be about $30-$40 cheaper per battery.

Some guys here run Optima or Cabelas brand gel-cells, but 99% of the boaters don't need that gel mat technology, as only features of installation, mounting, and overall robustness (from physical damage) is superior to a wet cell, nothing else.

 

[captbone]

For the extra money I would go with a 1000mca battery for your EFI engine. 1000 is required for optimax but is best for your engine. You can never have too much power. If I could find them cheap, I would have twin 8D diesel batteries.

Just my 2 cents.

 

[Mike2043]

Some guys here run Optima or Cabelas brand gel-cells, but 99% of the boaters don't need that gel mat technology, as only features of installation, mounting, and overall robustness (from physical damage) is superior to a wet cell, nothing else.

Not to hijack a thread but I have a question about this. I am going to be buying new batts. and I was going to get the sears gel-cells.@ almost $200.00 each I was under the impression that these style batts lasted a lot longer and you could leave them in the boat all winter with out a problem. I also read something about a discharge rate, that was like nothing compared to a regular batt.

Would I be wasting my money?

 

[Megabyte]

There is a huge difference between gel cell batteries and absorbed glass mat or "AGM" batteries.
For a power boater, AGM batteries are clearly superior. Gel cells are typically found on sailboats due to their much lower power draw requirements.

Having said that, I have a pair of Optima 'blue top' AGM's in my boat that have given me excellent service for the past 6 seasons.

When I replace the Optima's (which might be this year), I will seriously look at Lifeline AGM batteries, and the Optima's currently in the boat will be relegated to powering the battery-backup sump pump in my basement.

 

[Porkchunker]

I've gone to Group 31 batteries. Don't have the boat near to check the make/model, but I believe I got them at Bass Pro. They are dual-purpose (both cranking and deep-cycle). Had to modify the battery box trays to handle the larger batteries, but I now don't have the problem of the GPS/chartplotter and Radar and VHF running one down while fishing for croaker on the hook.

Somewhere in the projects forum is my post of the battery box modification. I think you'll find it searching for "Group 31". I'll see if I can find it.

BTW, the group 31 wet cell are much cheaper than those AGM and other Warp-Drive, Plasma-Ion, gizmos.

Dave

aka

 

[ppem45]

I have replaced many batteries in my boats over the years and have found that replacing only one battery at a time has proved to be the best way of doing it. That way when one dies you know you still have one that is one year newer. ie: I replace one battery every year and never have a problem.

 

[MaxOut]

I have replaced many batteries in my boats over the years and have found that replacing only one battery at a time has proved to be the best way of doing it. That way when one dies you know you still have one that is one year newer. ie: I replace one battery every year and never have a problem.

That's a good practice as long as you have them isolated. Otherwise you should always change them both as they are usually charged off one alternator. If you have one bad and one good battery with one alternator and no isolator you will kill the good battery. :wink:

 

[checker22]

Lookin to replace my Bats this next month. I've got 2 6Volt for my house and 2 12Volts for my engine. Lookin at the Dry Cell Bats, the Odyssy brand. Looks like they are starter Bats as well as a Deep Cycle. Having 2 12volts for my Engine if i loose on or in what ever case, but would i go, if i go with them, with 2 12volts on my house or go with one? Standard Bat switch, 1,2 or both. Sitting on the hook all night running squid lights, radios, ect...
Could i run the dry cells for the engine and stick with the deep cycle 6 volts for the house?
Also looking to get a shore cable to plug my little 1000 watt handa Gen to my shore power to chagen them.
Is there a certain charge for these dry cells that this would work?

 

[ryanc2]

Not to hijack a thread but I have a question about this. I am going to be buying new batts. and I was going to get the sears gel-cells.@ almost $200.00 each I was under the impression that these style batts lasted a lot longer and you could leave them in the boat all winter with out a problem. I also read something about a discharge rate, that was like nothing compared to a regular batt.

Would I be wasting my money?

I hope you wouldn't be wasting money, b/c I just bought those batteries. Group 31's that fit into a 27 tray.

 

[Porkchunker]

I hope you wouldn't be wasting money, b/c I just bought those batteries. Group 31's that fit into a 27 tray.

You mean to tell me I wasted an afternoon and some $$ replacing my group 27 battery trays?

Dave

aka