I need to replace my Group 27’s again this year. The current set barely lasted a season. The previous set lasted six seasons. My experience in general is that auto/marine batteries aren’t what they once were. What brands have you guys had good luck with lately?

If you're looking for cheap, Walmart. And I don't mean to disparage that choice. It's a decent battery at a good price. I have one in my truck (496 Chevy).
Spend a little more and get a better warranty, Batteries+Bulbs "X2Power"

So, interesting you should say that. I’ve had some good luck with the Walmart H8 batteries for Euro cars. They’ve been pretty solid. So I figured give the Wally Group 27’s a shot, not the same results. Just didn’t last. They were fresh June 23 batteries when I bought and installed them in June 23, but just never held charge well. First season was ok. Slightly weak, but would charge up fine while running despite no parasitic draws. They needed a charge every time I took the boat out last year. They’re stone cold dead now.

I’ll check out the ones you mentioned. Lowe’s also has Deka deep cycles for a decent price. East Penn (Deka) has historically made good batteries, I’ve been considering them.

Figured I’d see what others have had good luck with lately.

I always buy Walmart marine batteries. (25 years now) They are made by JCI. Bought 2 new ones 3 years ago.
https://www.walmart.com/ip/EverStart...5-CCA/20531539

I bought my Hitachi excavator in 2011. They 12v batts were not new. They're in series for 24v. The 4 cyl engine is not that big, about a 60hp diesel. I've ressurected them from dead a few times over the cold seasons. I'll likely replace them next season as maintenance. Insane life on them.

I have Mack batts in the Mack dump tandem axle dump truck. 12v. I have 2 in parrallel. I've had just one in, and was strong enough to start the 673ci inline 6 diesel.

I've had these since Dec 2017, and they gave out their last gasp last year. I didn't use them much from 2020 to 2024 though. I had a current draw in my system that dropped them down hard...they recoverred well.

My plan is to get new ones for the boat...and then switch them to the machinery after 2 years. Buy new for the boat.

950 cca

13" long
8-5/8" tall
6-3/4" wide

For a dual-purpose battery, if that fits your bill, I have had great luck with Odyssey batteries in my boat.

Are you using Deep Cycles as your starting battery?? That could be shortening the lifespan of them.

I am Griff. I’ve used DC batteries in every boat I’ve owned in the past 30 years. Never had an issue. I know some people run one DC for house power and one starting/charging for the engine(s).

It may also be that I’m just not getting out on the water as much these days. Sometimes a month or more goes by without use. Unfortunately, I can’t keep a tender on them when not in use.

Not only is a Deep cycle battery going to have a reduced lifespan when subjected to high cranking loads, it also may be detrimental to electrical systems because they're being asked to perform with less voltage than might be ideal.

My 350 Mag MPI would crank ok with a deep cycle - but it wouldn't fire because the PCM wasn't seeing enough voltage to fire the injectors. I changed to a starting battery and all is well.

As for the tender issue - have you considered a solar charger? They can deliver enough amps to maintain a battery, certainly better than nothing.

I'd get one starting and one deep cycle. They are designed for different purposes. I run a starting battery for each engine and have a deep cycle for my stereo. I always run Interstates. Mine usually last 7-9 years. No tender on them and I charge them every couple months in the off season.
Cranking Battery vs. Deep Cycle Marine Battery