Best Dual Battery Set Up?

One of our other members on the board was conversing with me via email asking about my battery set up. It turns out that both his 260DA and mine were delivered with two 27AMP Cranking Batteries.

When it comes time to replace these batteries, I was wondering what to do. I guess I am disappointed that Sea Ray didn't see fit to install at least one Deep Cycle battery for use as the "house" battery. Would that be the way to go in the future.........one Starting and one Deep Cycle? Or would two Deep Cycles be better? Or maybe I should leave well enough alone and just replace with cranking batteries? :smt017

You should always use deep cycle batteries. The best out there is the Delco Voyager, they cost a little more but my customers regularly get 5 to 6 years out of them.
Brad
 
Whats the cost and expected life of an AGM Battery? Does it warrant the extra cost? I keep hearing that properly maintained regular lead batteries are cheaper in the long run? I usually get at least 3 years out of mine and have gone 4 years on occasion?

I go through hundreds of batteries a year and find that regular lead acid is most cost effective and a better way to go. They need to be maintained which forces a boater to remove and clean electrical terminals annually. The gels and others get put in and forgotten. Two years latter they are calling me for a service call simply because of dirty terminalls and they boat wont start.
Brad
 
If you're not gonna do AGM, take a look at Interstate's SRM-29. This battery fits in a standard Group 27 box, but offers a little extra power. I put 2 of these in about 4 years ago and they are still going very strong.

Of course the answer to the original question here really depends on how you use the boat. I have found that I can run my fridge, stereo, etc all day and then run the fridge and a fan all night (and occasional lights, vacufulsh, etc) and still have cranking power the next morning on one of my 29s.
 
Sorento 25

You said:

"Optimas are great cranking batteries but do not have much capacity as a house deep cycle. I have one for a cranking battery."

The Optima D31M is a larger body marine battery with 900 CCA and 1125 CA.

I use two of the yellow top versions for my Motorcoach in deep cycle mode and two more for starts and have for years. What marine requirement are you thinking of that makes you say they don't have much capacity as a deep cycle battery. Am I missing something?

Very nice schematic by the way...
They excel at cranking and put out tons of power instantly, but you wouldn't want to use them for house or inverter batteries. Its the amp-hours ratings that are weak. My blue top D34M Optimas are rated at 55 and even my cheap deep cycle house batteries are rated at double that - 110 each. The D31M is only 75. My two 6V Trojans are 420 Ah.

If they supply enough capacity for your deep cycle house or inverter needs they're a great battery, but a flooded deep cycle is still your best Ah/$ value.
 
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