Battery Replacements on 2003 Marlin 300

[Blimjr]

I purchased this well maintained boat last year. I have 2 banks of (4) Cranking Interstate batteries on it now so I want to change out the batteries (over 3 years old) this Spring. I would like some input on keeping all the batteries as Cranking or should I mix in a couple dual purpose or Deep cycles into the mix. AGM's? Any suggestions or recommendations?

 

[Fishtales]

GW suggests Group27 starting batteries. I did mine with Duracells from Bulbs and Batteries last year.

 

[seasick]

I purchased this well maintained boat last year. I have 2 banks of (4) Cranking Interstate batteries on it now so I want to change out the batteries (over 3 years old) this Spring. I would like some input on keeping all the batteries as Cranking or should I mix in a couple dual purpose or Deep cycles into the mix. AGM's? Any suggestions or recommendations?

My batteries last 6 years. Unless you detect a drop off in battery performance, I don't see a need to replace. I am sure that some may argue the point but waiting till one seems to be getting a tad weak before replacing all,has worked for me.

There are a few factors that will adversely affect battery life: Hoe temperatures is up on the list. Batteries in the south don't last as long as those up north
Over-charging usually due to a not so smart battery charger or a bad motor regulator
Deeply discharging cranking batteries. They like high draw for short bursts unlike deep cycle that don't like high discharge rates but do like long and slow drain.
A lot of forks really praise AGMs. I am not so sure they are the best bang for the buck for my small boat.
Regarding the mix of battery types and what type they are,; If the current (pardon the pun) setup last 4 or 5 years with your typical usage, I recommend that you replace with the same types. Sort of "If it ain't broke, don't ix it".

 

[DennisG01]

How do you plan on using the batteries? Will you have lot's of time of battery use with the engines off or will the engines be running most of the time. Big difference in what a recommended battery type may be.

However, within a "bank", never mix battery types.

 

[RussGW270]

I wanted to add one or two batteries, for the "house batteries", just not sure where to start or store.. heh. twin outboards, the chances of both going bad at once seems slim, but I hate the idea of the electronics using those... I like to isolate electronics from engine batteries.. I know.. I am weird like that. Nice when they get charged by the engines, not so much if they suck down the starting heh.. I can always add a flexible solar panel to my top

 

[ScottyCee]

I like to isolate electronics from engine batteries.

This is my first boat with 3 batteries. They are labelled "house" "eng1", and "Eng2". I'm guessing that they are independent of one another, but I haven't analyzed yet. I believe that the three are identical marine batteries. Each has an "A/B/BOTH/OFF" 4-position switch.

My old boat had two (also labelled "engine" and "house") but when the switch was in the "A+B" position, they worked and charged from the alternator together. That is what I want the new setup to be - all 3 working in parallel for everything from starting the motors to running the line hauler, and charging together from either motor when running.

So what is the default wiring on a 1998 272? I'll take my MM out tonight and figure what I have, but are there any reasons not to parallel all three batteries? I do not have easy shore power access, so I definitely need the "house" battery to charge from the motors. I typically run a very low battery load, and always had something idling when I run my 40A line hauler. Which is a lot on shrimping days.

What I HOPE is that the 4 way switch banks them all together in the BOTH position. Any chance that this is the config?

Thanks for any advice!

 

[dogdoc]

I replaced mine with dual purpose from batteries plus. Use them for both cranking and house separated into 3 banks (cranking,cranking and house). I only use flooded lead acid batteries. Maintenance and charging (strongly rec a super smart charger maintainer desulfator) are paramount to battery longevity. I have used them in boats, golf carts and solar array battery bank and usually expect 90 percent plus capacity at 7 years old.

 

[RussGW270]

I have not gone down this rabbit hole yet heh. I am still on the engines. The last boat, a Triton 240 LTS Pro, .. I re-wired most of it and so had the ability to clean it up and design what I wanted. Still on the engines on this one.. heh.. this is a whole different beast, so will have to leave the advise to the experts

R