8D battery replacement

Thanks Burgermeister.. . Good information. I like the weight difference and the longevity. But after comparing things, the 8D has more of everything CCA,Ah, etc.
Again, on my small vessel the two batteries power everything. The house, the motors, the generator etc. I am hesitant to change things up.
Also mine are not to hard to remove. The both rest between the motors in a built in battery box. Straight shot down from the salon floor above. I tie a rope to each grab handle and my wife and I each handle one end of the battery together to lower and raise it. I also use a 2 x 8 plank to slide it up and down the steps and as a gang walk onto the boat aft deck.
It’s still is something I do not look forward to.

Yes, not much to physically check, no watering. That's one of the reasons I generally prefer AGMs too... although they're not magic and not without their issues depending on how some folks -- especially cruisers who don't often visit a dock -- recharge (or not).

"Same battery charger" depends on your starting point. It's a matter of matching what the charger can do compared to what the battery wants. You can get the Lifeline manual (for instance) and see exactly what voltages they recommend. Then you can compare that to voltages you charger can supply (sometimes depending on settings).

Some chargers have only basic settings (FLA/AGM, Gel), and the rudimentary settings may or may not match your battery requirements. Some newer chargers give you several different "profile" options and even a way to select exact bulk/absorption and float voltages, easier to match charger and batteries.

Lifeline, for instance, actually recommends lower bulk/absorption and especially float voltage than Odyssey... and then Lifeline tends to offer higher capacity in their 8Ds, while Odyssey emphasizes cranking amps.

(We had banks of 3x Odyssey Extreme G31s before, dual purpose start/house architecture, got 11 and 12 seasons out of those banks. This boat is setup for 8Ds instead, ditto dual-purpose architecture, and came to us with run-of-the-mill wet batteries with one bank in a difficult location for service... so I'm gradually switching to Lifeline 8Ds... with acceptable cranking amps but also slightly higher capacity than the Odyssey equivalent.)

-Chris