Battery Charger for 8D batteries - new to this

[JeremyD]

So I bought a 31 in February that's still in the yard - long story but I had to have the starboard ZF 220 transmission rebuilt and one of the Cummins 315/330 engines (I now have a ReCon on that side) . The other one is apparently under 300 hours so should last me.

The charger was shot when I bought the boat and I figured I could just replace it with a pro mariner or the like - well I can't do that with the two 8D's that I have in there. I also have a group 31 that's the starter battery for the generator.

So does anybody have a recommendation for an onboard charger that will work for 8D's? New to the diesel game.

[Carl]

Personally, I'd get rid of the 8D's.
8D's are huge, heavy, expensive and I believe overkill for our Cummins. I could be wrong, but my 6BT only requires 950CCA which is available in group 31. I have two starting batteries and a deep cylce house.

[Bruce]

A battery charger doesn't know whether it's hooked up to an 8d, 4d, 24 series, 31 series etc as long as the battery charger will charge the types of batteries, flooded, agm etc and they are the same voltage.

[JeremyD]

Appreciate the response - Maybe now is the time to replace the 8D's while it's in the yard. The prospects of having to change those out later is a little intimidating. Apparently the charger has to have an amperage that's 10% of the CCA or it will not charge - especially if the battery is completely discharged.

[Tony Meola]

Jeremy

A lot of the newer chargers will not kick in if the battery is below a certain level. For that you need an old school charger or if you have a jump pack, sometimes you can fool the charger to think the battery has enough juice and it will kick in.

Not sure if any of the newer marine chargers will kick in on a dead battery, but some of the manufacturers are starting to I know that NOCO now makes chargers that will sense a battery down to 1 volt but they are not cheap.

[JeremyD]

Yeah thanks - I am going with a couple of Odyssey group size 31 batteries. I have had good luck with them in the past. Florida heat is tough on batteries here - so I would rather replace an unknown now and have a baseline. I think the ProMariner charger will work OK for them - I don't plan on having a whole lot of things running while at the dock (charging) so should not have much of a load to begin with.

[Amberjack]

Jeremy--Is there a reason you're looking for a charger that will work for completely discharged batteries. Unless I'm missing something in your application that would never happen. They just don't get that low and if they do something is wrong and needs to be fixed.

[JeremyD]

No No - the batteries - the 8D's are of an undetermined age. When I bought the boat in February the onboard charger took a poop. So just wanted top replace that. I sent the yard a charger to install - the charger had a tag on it that said it didn't work on 8D's or 4D's. SO my first course was finding a charger that would work with the batteries - but after some thought - decided that money would be better spent replacing the batteries.

So I am replacing them with some decent Odyssey group 31 batteries - and will keep the charger that I already bought.

[Bruce]

OD's are agm. Make sure the charger does agm and your group 31 is the same type also.

[JeremyD]

You bet - The charger is compatible with both.