21 EC Starting Battery Toast?

[TylerFromEverett]

Hello:

My assumption is that my starting battery is toast. Before I replace possibly fry out a new battery, I wanted to run a couple things by you all.

Symptom:
Boat won't start. House power works.

Diagnostic testing:
Starting battery voltage (110v charger not plugged in) = ~8 volts
House battery, (again no 110v charger) = 12.6 volts
110v onboard charger plugged in, both batteries read around 14 volts (can't remember for sure, but they're normal)
Boat WILL start with 110v plugged into the charger
Batteries both read around 14 volts with engine running (so alternator is working)
Turn off engine, unplug 110v charger, engine won't turn over, starting battery reads ~8 volts, house reads 12.6 volts
Plug in 110v charger, engine fires up

Diagnosis:
Starting battery is toast, won't hold a charge. Needs replacing. Battery is 6 years old.

Confirm?

 

[bob daily]

Yes!

 

[Capt’nKarl]

Yes. Getting 6 years out of a battery is fantastic so you must be doing it right.

 

[Cutwater28GG]

in case you need a third opinion. 😀 Yep time for a new one.

If you have 6 hours on the house batteries be prepared for those needing replacement too

 

[iggy]

I hate to say this, but some of my batteries are hitting 7 to 9 years old. I think to it depends on how you take care of them.

I would do a load test. But thats me.........

 

[TylerFromEverett]

Any recommendations on a replacement battery?

 

[Cutwater28GG]

you will want to keep the chemistry the same as the other batteries as the single charger needs to manage them all. Id use the same type as before if I could as you have had some good life there.

If you are replacing all, then its a different story. The factory used these for a while

https://www.amazon.com/D5751-UB1211...=UB121100&qid=1598321769&s=electronics&sr=1-2

the Northstar brand has a good reputation

 

[BradOwens]

We found the AGM batteries sold by Pacific Power and Batteries in Everett to be good, and as cheap as any AGMs we found.

 

[TylerFromEverett]

you will want to keep the chemistry the same as the other batteries as the single charger needs to manage them all. Id use the same type as before if I could as you have had some good life there.

If you are replacing all, then its a different story. The factory used these for a while

https://www.amazon.com/D5751-UB1211...=UB121100&qid=1598321769&s=electronics&sr=1-2

the Northstar brand has a good reputation

I bought my boat used from RT factory. It’s a 2014. I always thought it was a little weird that it had a flooded LA for starting and am AGM for house with a single charger for both. I had to replace my ProMariner charger right after I bought the boat. The dude at PeoMariner told me that I can set the charger to “gel” (I think, I have to look back) and the profile would be “suitable” for the mixed batteries and I would be fine. He had some technical reason for the charging amp range for both, but I can’t recall. You seem to be an expert on most things (I mean that sincerely) so I value your 2nd opinion.

 

[iggy]

Any recommendations on a replacement battery?

https://www.odysseybattery.com/applicat ... batteries/

Look at their warranty. Four year replacement.

This is all I use and as mentioned I am getting 7 to 9 years life out of them.