Marine Batteries

[MasterBaiter]

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.

[cdavisdb]

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.

[BigLew]

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.

[Old'sCool]

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.