I thought Deka was a a premium deep cycle. Never have used one. In my boat when I was fishing two to three days a week and fishing tournaments every weekend I tried a variety of trolling motor batteries. Trojan had a great rep, but for me started losing capacity after about 11-12 months. The dealer said if they load test at all they are still good so no warranty. Never bought another Trojan. Way to epensive for that s*it service life and poor service. I tried a couple brands of deep cycle AGMs and got about 3 yeas use out of them. Once when I was short on cash I bought a set of WalMart Maxx Deep cycles in group 29 size. I got 18 months out of them and a free replacement. They were half the price of the cheapest AGM deep cycles. So I have been using the WalMart group 29 deep cycle Maxx batteries in my boats ever since.
Now trolling motor batteries in a boat see pretty hard use if you fish a lot. They see a significant discharge every time you go out, and then get charged when you get home. I suspect its possible in a lighter use they might last a little longer. I have been using WalMart batteries in my truck and tractor for years now as well. I get better life out of a Walmart tractor battery then I got out of the insanely priced original John Deere battery. The one thing is I always buy the BEST' grade battery WalMart offers rather than the cheapest.
I was hearing great things about Dakota Lithium and was considering biting the bullet on those for my boats (very expensive), but a couple users who have had problems have reported that Dakota Lithium will not respond to them with issues on in warranty batteries. I'm not sure I want to gamble the price of lithiums just yet. Not even the price of "cheaper" Chinese lithium batteries on Ebay, Alibaba, or Amazon.
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Thanks. It appears that Johnson Controls makes the WalMart Everstart Marine Group 29 battery which has a rated capacity of 122Ah, not bad for $90. It's rumored that Johnson used more recycled lead than East Penn, which makes their flooded batteries self-discharge faster in storage. Have you seen that?
12V 100Ah Lithiums have fallen to and below $400, even $229 on Alibaba, and I'm watching for reviews. I know from being a battery tech that the lifespan of Lithium can be under 1 year or over 10.
Although I can't reveal specifics the 1 year battery was used outdoors in Arizona.