Difference between marine & RV deep cycle AGM batteries?

[abosely]

As the title says what is the difference between Marine and RV, deep cycle AGM batteries?

I laid out my battery mount location under the 69’ SIIA tub and don’t have as much room as I thought I did.

So need to use two AGM batteries mounted on their sides, one start & one house battery.

For example, Lifeline has Marine and RV deep cycle batteries.

But I can’t find what the difference between them is.




The white is mock-up, will finalize exact locations when crate with 300Tdi, Stubby R380, LT230 & RM springs get here & can mount axle & driveshaft to check clearances.

More on my FB page, 69’ Series SIIA Build.

Cheers, Allen

 

[MANUCHAO]

Between Marine and RV, the only physical difference is that the marine batteries have an additional threaded post (this is to run a trolley motor)... looking at the weight on say a "group 31" battery from two different manufacturers/ brands would be more telling, as to which is the better battery...

 

[Ducky's Dad]

Don't know about Lifeline. With Odyssey, the only diff between regular and marine is the extra pair of threaded studs, designed for lower current stuff like trolling motors and refrigerators. Same for Northstar, same battery with extra studs. Optima gets more confusing. Their marine Blue batteries come in two persuasions, one based on the Red starting batteries, but with the extra set of studs. The other Blue marine battery is based on their Yellow deep cycle battery, also with the extra pair of studs. One version of the Blue marine Optima has a light gray case and a blue top, the other has a dark gray case with a blue top. I think the light gray is based on the Yellow and the dark gray is based on the Red, but double check my memory before you buy anything.

 

[john61ct]

Yes those labels are pretty meaningless other than external physical details.

For true deep cycling performance & functionality, especially longevity, you need to stick to known-good vendors who can be trusted.

All those mentioned above except Optima are great for deep cycle AGMs.

There's a different handful for FLA, which is better value and lasts longer, if you don't actually need AGM.

 

[DLTooley]

Weight per AH should tell you a lot. But I am not sure exactly what. The heavier the better for deep cycle performance. AGM may differ from Flooded Lead Acid based on construction method.

 

[luthj]

To my knowledge, and based on Lifelines published data, the Marine and RV batteries are exactly the same inside.

There is a huge variety of battery designs. Generally "marine" batteries are just a cross between a starting battery and a true deep cycle. These types are often much cheaper than true deep cycle. They are not worth the money for a deep cycling application.

I believe most AGM mounted on its side will see reduced capacity (around 5%?). I am not sure of the mechanism, but the recombination catalyst in sealed batteries in usually mounted on the top, so that may be the cause.

If you can swing the cost, lifeline batteries are pretty damn solid. They charge fast, have low sag under load, and are designed for equalization (only when called for, not monthly!) They are also very compact for the AH.

 

[john61ct]

Yes if you need to spend the extra on AGM and can coddle them properly to get a good lifespan (easier with FLA)

then Lifeline is a top quality maker.

Once you're within that strata, "marine" is irrelevant, and you can trust their "deep cycle" definition, even get the specs, graph showing #cycles vs DoD%, etc.

Odyssey and Northstar are the other two good AGM in the NA market.