Battery replacment

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fishingdad

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Feb 20, 2020
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Fluid Motion Model
R-23 (Outboard)
Hull Identification Number
FMLC3042B616
Looks like I will need to replace the batteries in my 2016 30CB. Is there a difference or preference between the group 31 and group 30H (original) ?
 
Sorry, can't speak to which group is better, but depending on how long you plan to keep your boat, and if you spend much time anchoring for extended periods of time, I would investigate Firefly AGM's... life expectancy is greater and you can use more battery capacity before recharging... they're a little spendy, however.

Good luck and stay safe,

Bob
The Doghouse 2
 
Hi I found this site excellent. This how to site is one of the better information sites I have found. Take a look very informative. I have rebuilt a few boats and this was a go to site for electrical. This article clarifies what to look for in batteries.
https://marinehowto.com/what-is-a-deep-cycle-battery/

Hope this helps.
Glenn
 
I looked at the Firefly and did not think their warranty is that good. Batteries+, Odyssey, and Northstar have 48 to 60 month replacement.

As to battery size, if your house bank consists of 200Ah capacity AGM batteries, the maximum capacity would be 45 percent of 200, or roughly 90Ah. A 90-amp rated alternator would be required. Unfortunately, mounting a large-case alternator is not that easy in many boats. In other words, yes you can go bigger keeping this rule in mind.

I have seen boats with bigger banks. As not to burn out or melt the ALT. They run their genset for 20 to 30 minutes to recharge the batteries so the ALT is not taking the full load.
 
If you do change to a different battery type then what came with your boat make sure you reset your battery charger to the appropriate setting.....you would find this info in the charger manual.

Jim F
 
The 30H is considered a heavy duty battery, very close to the same size as the group 31. If you have universal UB121100 group 30 the difference group 31 is the dimensions and possibly CCA depending on which one was installed. The difference between the 2 are minimal. The group 31 will fit in the same tray as the Group30. The standard size for marine use is Group 31.What ever battery you use confirm the engine battery matches the requirements for the CCA/MCA for a D4 1150 CCA.
 
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