Maintenance Free Battery

[menzies]

I have one of these 4Ds installed recently for the helm instruments. I was going to pull the plugs and check the levels but saw that it is "maintenance free."

Does this actually mean that it is completely sealed by the plugs and does not need topped up by distilled water?

 

[DavidM]

Ok, you have a separate battery that powers the helm instruments, similar to a bow thruster battery in the bow. Is it located at the helm and how is it charged?

Such a battery cycles very little since 99% of the time when you are at the helm the engines are running and they are charging it (presumably). In fact I am surprised you need a battery up there if that is where it is and equally surprised if it is down below with the house batteries.

But in any case since it doesn't cycle much if at all then it is like a starting battery and maintenance free, sealed FLA batteries should be fine for that service. Although I would prefer an AGM for really maintenance free.

David

 

[dhays]

I have one of these 4Ds installed recently for the helm instruments. I was going to pull the plugs and check the levels but saw that it is "maintenance free."

Does this actually mean that it is completely sealed by the plugs and does not need topped up by distilled water?

My boat came from the factory in 2010 with Chinese built SLA batteries for engine start, house bank, thruster bank, and genset start. By the time I bought the boat in 2016, the thruster bank and engine start battery had been replaced by the PO with Lifeline AGM. The day after I took delivery of the boat the genset SLA battery died and I replaced it with a Group 24 AGM. Last year I finally replaced the house bank. They had lasted seven years without any type of service. The PO used the boat a lot and spent a lot of time out anchored and I don't know deeply or frequently they were discharged. The boat has a well put together charging system so they were regularly brought back to full charge. They were still working fine, but my impression was that they had lost a fair amount of capacity so I replaced them.



My point is that a SLA battery can last a lot time if it is treated well.

 

[AusCan]

Sealed lead acid batteries 'can' last a long time but often don't because its not a perfect world. If they are over charged or cycled hard they will still use some water and you cant top them up with ripping off the top casing. The manufacturer could easily make them refillable with a resealable top, but that would not be as profitable.

I'd pay just a little more and go with AGM.

 

[menzies]

Ok, you have a separate battery that powers the helm instruments, similar to a bow thruster battery in the bow. Is it located at the helm and how is it charged?

Such a battery cycles very little since 99% of the time when you are at the helm the engines are running and they are charging it (presumably). In fact I am surprised you need a battery up there if that is where it is and equally surprised if it is down below with the house batteries.

But in any case since it doesn't cycle much if at all then it is like a starting battery and maintenance free, sealed FLA batteries should be fine for that service. Although I would prefer an AGM for really maintenance free.

David

David, my boat runs on 24v. The 12v is to power the stuff that runs 12v - chartplotters, GPSs, etc.

 

[dhays]

Sealed lead acid batteries 'can' last a long time but often don't because its not a perfect world. If they are over charged or cycled hard they will still use some water and you cant top them up with ripping off the top casing. The manufacturer could easily make them refillable with a resealable top, but that would not be as profitable.

I'd pay just a little more and go with AGM.

When I replaced my house bank, I did use AGM. However, there is more than a "little" cost difference between SLA and AGM.



My own preference would be standard LA batteries that can be maintained. I've had great success with those in my sailboats. However, there are some applications where that is difficult. For those situations, a SLA may work great if you don't want the faster CAR that an AGM offers.

 

[DavidM]

David, my boat runs on 24v. The 12v is to power the stuff that runs 12v - chartplotters, GPSs, etc.

Aha. So it has a dedicated charging system that converts your 24V house power to the 12V that the helm needs. Then the SLA battery will be fine and should last a decent time as others have noted above.


But you don't really need a 4D as the battery is only acting as a buffer between the 24v and 12V system. When it finally fails a good Group 31 AGM will work just as well.


David

 

[menzies]

DC Panel.

 

[hmason]

I have one of these 4Ds installed recently for the helm instruments. I was going to pull the plugs and check the levels but saw that it is "maintenance free."

Does this actually mean that it is completely sealed by the plugs and does not need topped up by distilled water?

In answer to your question, the plugs unscrew. Use a broad screwdriver or a 25 cent piece works fine. You can add distilled water if needed. The guy that installed my batteries told me that although they say maintenance free they have vents on the sides and do lose water over time. And yes, I did need to add water on occasion. (Answer to the next question--yes I do have a smart charger.) Howard