New Battery?

[Rebel112r]

I need to replace my generator start battery. The current battery is a agm 150AH monster. Slightly smaller than a 4D, but longer than a group 31. Dimensions approx 19 x 7 and weighs 100#. This batt does nothing but start my Northern Lights 6kw 673 genset. I have checked Northern Lights website, to try and find amp hr requirements of batt but have not found an answer. I had an old lead acid group 24 laying around, which checked OK on my load tester which Is normally in my mercury 15 hp powered skiff. Installed now temporarily for genset, and it works fine. Any reason why a new Group 24 quality batt, is not sufficient for this job? Thks

 

[DavidM]

A good Group 24 will start it fine. But go for a Group 27 if you are going to buy a new one, for a little more safety factor as it ages.


David

 

[FlyWright]

I'd definitely go with the 24 if it provides redundancy.

If you need the genset but not the dink, viola! You have a spare. (Works vise versa, too!)

 

[tiltrider1]

Group just means the physical size of the battery. When a battery lists Amp hours it usually means a deep cycle battery which is usually low in Cold Cranking Amps. What you want is a starting battery. Any battery with 400 or more CCA is all you need. More CCA than 400 Is unnecessary. As batteries age the CCA does diminish, so there is some logic in over buying CCAs just don’t get carried away.

 

[Rebel112r]

The group 24 that was put in was just a test, to see how the genset cranked. The battery is old and abused, and will go back to crab skiff until it dies. The genset cranked just fine with it. Will pick a new flooded batt for the genset. The big battery removed was built in 2010. It still was starting the genset just fine, but I had to replace the regulator on genset as it was bad, and I thought the cause may have been the battery. Battery will be tested tomorrow. Thks

 

[dhays]

I need to replace my generator start battery. The current battery is a agm 150AH monster. Slightly smaller than a 4D, but longer than a group 31. Dimensions approx 19 x 7 and weighs 100#. This batt does nothing but start my Northern Lights 6kw 673 genset. I have checked Northern Lights website, to try and find amp hr requirements of batt but have not found an answer. I had an old lead acid group 24 laying around, which checked OK on my load tester which Is normally in my mercury 15 hp powered skiff. Installed now temporarily for genset, and it works fine. Any reason why a new Group 24 quality batt, is not sufficient for this job? Thks

Dan, my genset battery died right after I bought Kinship. I put a Group 27 AGM in its place and it has been working well for 2 1/2 years. Never any problems starting the genset.

 

[koliver]

Dan

Depending on location,you may be able to just run a cable from your main start battery to the genset and reduce overall weight by 100#.
I have one start 4D that starts two mains and the genset, plus works the windlass. I replaced it a couple of years ago after 12 yrs of flawless service.

When your dinghy battery dies, I would downsize it too. No need to haul that G24 around when a much smaller size will do the job. My Honda 40 has started for its whole life on a motorcycle size AGM, that also hauls my prawn traps all summer long.

 

[dhays]

Dan



Depending on location,you may be able to just run a cable from your main start battery to the genset and reduce overall weight by 100#.

I have one start 4D that starts two mains and the genset, plus works the windlass. I replaced it a couple of years ago after 12 yrs of flawless service.

If Dan’s boat is setup like mine, it would be very easy. However, the Group 27 that I use is very lightweight and provides some additional redundancy. In the unlikely event of both house and start battery getting drained, we can always start the genset.

Having said that, if my genset battery had died now, instead of after owning the boat for a few days, I may have made the decision to combine engine start and genset start batteries.

 

[ranger58sb]

The group 24 that was put in was just a test, to see how the genset cranked. The battery is old and abused, and will go back to crab skiff until it dies. The genset cranked just fine with it. Will pick a new flooded batt for the genset. The big battery removed was built in 2010. It still was starting the genset just fine, but I had to replace the regulator on genset as it was bad, and I thought the cause may have been the battery. Battery will be tested tomorrow. Thks

You had an AGM battery there, and it would be easy enough to replace with another AGM. They don't self-discharge very much...

One advantage, maybe, depending... is that if your genset will charge it's own battery, you don't necessarily need to connect another charger to it. IOW, if you have a mullti-bank charger, you could divert some of the chargers capability to house batts...

Our genset starter is a Group 34. Similar to a 24, I think...

-Chris

 

[Rebel112r]

I picked up a 800 cca Group 24 today. Had my Sonic load checker along, so hooked it up to the threaded terminals and did a check and new battery failed, showed 12.8 volts, but could only pull 340 Amps. The salesman looked at me and said let me show you something. We hooked meter up to auto studs as battery has both and rechecked, meter showed CCA of 900 amps. So if you load check a battery make sure you are testing to lead. The copper spade terminals that fit over threaded studs mate copper to lead. In the past I have added eye terminals on top of nut on threaded terminals and just added another nut and all was good. Don’t know if it was just the sensitivity of meter, or difference in SS and lead in ability to conduct the current. Might only be a problem when testing, but was interesting, and this old fart may have learned something.

 

[BruceK]

Checking my Onan MDKD 6.5 Manual for battery recommendation, I note the genset alternator output is 10amps. Glad I have the solar maintenance of this batt.

 

[ranger58sb]

I picked up a 800 cca Group 24 today. Had my Sonic load checker along, so hooked it up to the threaded terminals and did a check and new battery failed, showed 12.8 volts, but could only pull 340 Amps. The salesman looked at me and said let me show you something. We hooked meter up to auto studs as battery has both and rechecked, meter showed CCA of 900 amps. So if you load check a battery make sure you are testing to lead. The copper spade terminals that fit over threaded studs mate copper to lead. In the past I have added eye terminals on top of nut on threaded terminals and just added another nut and all was good. Don’t know if it was just the sensitivity of meter, or difference in SS and lead in ability to conduct the current. Might only be a problem when testing, but was interesting, and this old fart may have learned something.

???

Installing the battery in the boat would be a copper-to-lead (wire to SAE post) or copper-to-SS (wire to threaded stud) connection.

???

-Chris