I have one battery onboard for the outboard and its from 9/2022. Its not holding a charge like it should so I am replacing but it got me thinking if there is a recommended timeframe in which to go ahead and replace for good measure?
There is a lot of factors that play into it, but 3 years is probably pretty average life. In perfect conditions 4-5years
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Heat is a top killer of batteries. Another is running them below 50% capacity, which seems asinine, but lead acid batteries have a high drop off rate at 50%. Going completely dead is hard on them.
AGMs handle heat and vibration better, so if you are going to replace, check them out since they have a longer lifespan.
Also, you can have the capacity of your current battery checked at an auto parts store. If you are below 80% and under 3 years, some manufacturers will replace the battery. Worth checking into.
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Batteries today don’t last for ■■■■. Couple 3 years is about it, unless you luck up and get a “good un”
Three years - if you’re lucky.. maybe a year or two more if it’s only used as a cranking battery and getting charged all day long each day as you run it… Deep cell batts - the more you discharge them - the less their capacity is so like I said.. three years - maybe…
Made the switch from wet cells to lithiums last year for my trolling motor batteries (two 100AH lithiums) - and couldn’t be happier. My expected life span - 10 years… The only drawback… they’re not what you want for a cranking battery… just not built for that use…
Mine are AGM I believe and coming up on 3 years so the thought of replacing and going with lithium on the troller has been in my head lately. Is there a reliable way to test them? Is there a way to “tell” if they are struggling? So far they’ve been fine and can run the troller no issues and never felt weak when cranking. I keep them on an onboard trickle charger in the garage.
A way to test non starting/cranking batteries is putting a know load on the battery and seeing how long it lasts. You should be able to find a voltage table for you battery that should tell you your 100% voltage and 75% and so on.
This is a good read State of Charge
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Just a little FYI, since lithium battery technology is advancing rapidly. There are now lithium batteries built specifically for cranking applications. I have no idea how well – or poorly – they compare to lead-acid batteries. But a search of some of the lithium battery manufacturers’ sites will show lithium cranking batteries for automotive and marine applications.
Thanks everyone
Hipshot…from what I understand, it’s more about the engine’s ability to utilize a Lithium vs the battery itself. To my knowledge, it appears that only Mercury (Late models) are compatible with Lithium as a starter…(has to do with output to the battery and Reserve Capacity and the how the alternator outputs to the battery). Mercury / Brunswick owns Relion battery manufacturer…thus the reason they are using and recommending Lithium.
I got an incredible deal on two 100AH Relion’s which are recommended for the Mercury XS115. so, I went with these and saved over 100 lbs of weight for my MA17.
There is a great video on the Relion site and the use of Lithium in the build of a Chithum skiff…check it out.
DC
Regarding lifespan…for cranking batteries, due to the Reserve Capacity requirements, I used Interstate wet cell - series 31 or 27. Lasted 2-3 years max, and that was watching the fluid levels.
For TM - I went DEKA’s series 31’s, AGM’s, they would usually last me 3-4 years, MAX…
BTW, I found Batteries PLUS was the best location for buying batteries (Duracell/DEKA) and Boat Owner’s warehouse for Interstates…Batt + no questions asked on problems…I hand one Duracell go bad and it was replaced next day after testing.
DC