Amps Over Heating

[rdlangston13]

what are the different groups of batteries?

[MLA]

what are the different groups of batteries?

"Group" is battery speaker for size. Basically like a trade # on an automotive light bulb.

[rsinger]

Now I've heard everything. A boat that has got to be plugged in when it's out of the water.

You folks are running some pretty nasty systems.

Pretty soon these boats will come with a separate generator to keep the sound system batteries charged.

[EarmarkMarine]

^^^ Actually using a gen is very common on pontoons and other boats that only feature stators on their outboard motors. Also, its not a bad idea for long weekend camping trips where AC power is unavailable. So its one more thing to add to your boating list!

David
Earmark Marine

[cab13367]

what are the different groups of batteries?

The larger the #, the larger the physical size of the battery and the larger it's electrical capacity, in general.

[rdlangston13]

The larger the #, the larger the physical size of the battery and the larger it's electrical capacity, in general.

So what is the best bang for my buck battery wise? I want to go with 2 stereo batteries and 1 starting battery. I know the optimas are good but i hear i can get something just as good for a fraction of the cost. What would that be? I want something maintenance free.

[bbuhtz]

+1! I went with two Group 29 marine deep cycles from Walmart for my stereo bank, 125 AH, $85 each.

I also have 3 of these Group 29 marine deep cycles from wally world and they perform fine. Save the money for an ACR and a pro20 charger, well worth it.

[EarmarkMarine]

Battery sizing can be a little confusing because the numbering system isn't entirely sequential.
Group 34. Common to compact racing batteries and AGMs like an Optima. Similar to a group 24 but not as tall.
Group 24. A standard size for starting and marine batteries. Stock in most towboats.
Group 27. Larger dimensions and capacity over a group 24. Requires a larger 27 case/lid or tray/bracket.
Group 29. For all purposes this is the equivalent of a group 31.
Group 31. Larger dimensions and capacity over a group 27 and will often fit in a group 27 case or bracket.
Its really simple but usually as the battery becomes heavier and larger the battery has more reserve capacity. You could almost skip the amp/hour rating and go purely by the weight.

David
Earmark Marine

[rdlangston13]

So David, what battery set up do you recommend for my system?

[EarmarkMarine]

rd,
Best bang for the buck is going to be a wet/flooded battery and you will really only have to check fluids three to four times a year if you are charging them correctly. AGMs will not provide greater amp/hour capacity for the size and weight and certainly cost more but have numerous other and valuable advantages. We have had zero problems with Optimas and have boat owners running the same batteries for five seasons...but they are disciplined in their battery care. Deka makes a premier AGM and will provide a little more capacity.
In general, a deep cycle will have no trouble turning over a small block in warm weather. So I like a deep cycle battery for the starting side also since there is a certain amount of leveling that takes place after a long play at rest. With repetition this is unhealthy for a standard cranking type battery.
So a single group 34 or 24 for the starting. For the stereo battery bank you need to match up your anticipated play time and how hard you play the system with your total system power and amplifier efficiency. A single group 27, 29 or 31 would be minimum while dual 29s or 31s should be maximum. Remember that the larger your battery capacity is the more dependent on AC shore charging you will become to maintain healthy batteries. And you've got to have the right charger capacity to match up with your collective amp/hours. With all the stereo and battery investment, don't go cheap on a minder/tender/maintenance/trickle charger. Making the right choice here is just as essential.

David
Earmark Marine