Battery Up Date and Charger Question

[wakeup]

Following on from my how many amp hours do I need for my 28 foot boat post.......

The background

I since procured the services of a Marine Electrical engineer. My boat was originally set up with 2 x 110ah units wired in parallel giving on thunking great battery of 220ah as starter and domestic in one (This is how it came from the factory ! Jeanneau) Two thunking greater battery switches isolated both pos and neg connections.

The Electrician hauled out the two batteries and they were found to be 50% of capability when measured on his battery diagnostic computer. We measured the battery bay and decided that we could fit 3 new x 115ha batteries in the bay, 2 for domestics and 1 as a dedicated starter. He rewired the outputs and inputs with corresponding battery switches but interestingly also added a voltage sensing relay so that once the starter batt was charged, the input circuit would open to charge the domestics from the alternator also. Touch wood this should adequately run two small fridges, windlass and radios and be able to start the engine after 6 hours at anchor. I also obtained digital remote output unit for the charger so I can see how many amps are being drawn and battery status also as the boat wasn't fitted with one.

The Question.

The original batteries were clearly cooked before their time. Marine Eng said that it was likely that the boost function was set to on on the charger, it was. He recommended that I switch it off so that it only charges in absorption and floating mode? Do you think this is the right way to go. He told me that the batteries will last longer, but charging will take a lot longer however. the charger's manual recommends the opposite.

Thanks for any input.

 

[rafiki_]

It depends on whether the original batteries were starter or deep draw batts. If starter type (hi instant current for starting), these degenerate very quickly if allowed to discharge below 50% capacity, which could have occured with your set-up. Normally the boat should have different types for starting and domestics, therefore it sounds like the system was not set-up to deep draw for the domestic use.

My boat has 2 engines and 4 batts. 1 for domestic and 3 for starting the 2 engines, and running the bow thruster and anchor winch. Therefore the domestic is the deep draw type, the others are starter batteries, as the bow thruster and winch will only be used with the engines running.

However, I feel I need to increase my domestic capacity so will probably fit 1 or 2 more domestics.

 

[DavidJ]

[ QUOTE ]
The original batteries were clearly cooked before their time.

[/ QUOTE ]
How long was that? If they gave you 7 years of service I would think that fair enough and not change anything.

 

[wakeup]

3 years from new.

 

[ccscott49]

Down to 50% capacity in three years? Depends how they were used and how often. 3 years isnt that bad, for say a liveaboard, but not for the occasional weekend etc. Also depends on the type and manufacturer. Cheap batteries are just that, cheap!

 

[wakeup]

very occasional use as a day boat, only ever slept on twice.