Marine Batteries
 

I already know I'll need to replace both of my batteries for next season. I usually just leave this to my marina's service department, and usually pay way more than I should- not this time! Any suggestions for buying? Does it make much difference or are they all basically the same? Thanks for the help.

Re: Marine Batteries
 

The right size and type battery is important. You should have sealed, marine-grade batteries. Most common sizes are group 24 and group 27 starting batteries, and gel batteries are MUCH better than lead-acid.

Re: Marine Batteries
 

I HAVE THE DEKA AGM'S, WEST MARINE SELLS THEM AS WELL REBRANDED, AND IF YOU CAN WAIT FOR A SALE YOU CAN SAVE BIG BUCKS.

Re: Marine Batteries
 

All batteries are not the same! Even within Johnson controls who makes a huge number of brands at numerous price points, the quality ranges from top of the class to depths of Bowery gutters in bad times.

I also have group 27 Deka AGM, deep cycle for house and starting for starting. Bought them from a battery shop for nearly half of the West Marine price.

Thus far I've had better luck with AGM than gel, but I think the manufacture quality may have more to do w/that than the type.

If you have a newer motor you may have to go up to a Group 31 to get desired cranking amps (e.g., I think Optimaxes require at least 1000 cca).

I think a key to longevity of any battery is that it be used or charged regularly. Even Concorde and Rolls batteries will fail if they just sit...

Re: Marine Batteries
 

I remember one of the CSC members becoming a marine battery rep, maybe if someone remembers his name they can provide him as a reference and he can help you out. Not sure about his location.

Re: Marine Batteries
 

I replaced mine last year with Optima blue tops and have had a Guest on board charger.

Re: Marine Batteries
 

The AGM can be mounted pretty much anyway way you want to mount them; upright, on their side or end and I believe even upside down.

Re: Marine Batteries
 

Whatever battery you choose, make sure to have them connected to a "smart charger" all the time, one that matches your battery type. I use West Marine batteries and adding the right charger more than doubled the life of the batteries.

Re: Marine Batteries
 

do u guys leave your batteries hooked up to a charger all the time when not in use?

Re: Marine Batteries
 

Yes

Re: Marine Batteries
 

I think leaving a charger on all the time depends on the battery and charger. Lead/acid batteries would boil away and ruin the battery with your typical charger. You would need one that would switch to a "maintain" type setting after full charge. I use an isolator between my 2 and the engine seems to do a good job of keeping them charged.

As far as type of battery, I use Sears DieHard lead/acid. They are not expensive, I have had good luck with them in my vehicles, and everywhere I trailer it there is either a Sears or Kmart for an exchange if there was a problem.

Re: Marine Batteries
 

The old style chargers were transformers, the output of which was hard to control precisely. With the exception of Sentry, which had controls which could completely shut off, you could just about count on transformer chargers burning up your batteries if you left them on, certainly shorten their life. The newer battery chargers use some kind of solid state electronics to make the switch from ac to 12v dc. With solid state, its easy to get very precise control of output. They automatically go to a trickle or "float" charge once the battery is fully charged. That won't burn your batteries and keeps them exactly where they need to be, lengthening their life. You have to make sure the charger is set for your type of battery (for example,lead/acid uses a different cutoff voltage from gel)and that the charger is working correctly.

Re: Marine Batteries
 

Tucker,

For those of us who do trailer our boats you make some excellent points with regards to readily potential availability of replacement. Few, if any of us use significant current between engine operations so the deep cycle and AGM advantages are not generally fully utilized. Further, generally speaking, the lead/acid type battery delivers higher usable amperage for cranking engines than the other designs. The also recover faster and are replenished more quickly than their other design counterparts.

On larger boats with more electrical demands when at rest (refrigerators, TV's, A/C, etc.) deep-cycle and AGM designs become more practical design for those applications. Further, most of our boats depend on our propulsion engine for our electricity generation and it is not ideal to mix battery types for simultaneous unregulated charging purposes. Mixed battery type configurations are optimal when a charging regulator is appropriately sized and installed in these situations.

Re: Marine Batteries
 

I've run AGM (Optima) on two boats and many years of service. I've never had a problem with 12v being available. They are much safer batteries than traditional lead acid. This is valuable piece of mind when 50 miles offshore.