Cranking Battery issues, here we go again!

[Pat Dilling]

We have a 2021 Z19 Pro. It is equipped with 3 graphs, two Humminbird Helix 8s and one Helix 10. It does have the Humminbird network hub, installed at the factory. All wiring is standard Nitro from the factory.

Previously I was having cranking battery issues, first with the original Interstage 31 AGM. At about 8 months old, it would lose voltage after 4-6 hours of fishing. I do not use live wells very often as I do not tournament fish. It would drop enough (11.4v), that it would not crank the Pro XS 200 4 stroke and I would have to use the jump switch to start it. BPS dealer replaced the Interstate battery. About 4 months later, the replacement battery did the same thing. I believe the Interstate AGM 31 does not have the spec CCA, it has 925, vs the 975 spec from Mercury. So, I bit the bullet and bought an Odyssey group 31 AGM with 1150 CCA. It has worked great until last week, 14 month old, it started doing the same thing on two seperate fishing trips. After 3 battery failures, I am beginning to think there is someting wrong with the boat wiring that is causing batteries to deteriorate.

Has anyone else experienced similar issues? I have sent an email to the vendor I bought the Odyssey from to enquire about warranty procedures.

Help please!

PS I have a NOCO Genius 3 bank 10 amp charger that came with the boat. I have added a Stealth 1 charger that charges the trolling batteries when the gas motor is running.

[Andrebass]

GEEZ PAT! I hope you resolve this issue. as I know you have been having major issues with this. You have gone above and beyond what is asked and still having original problems with.

I on the other hand, just been dealing with trees falling on my boat.

Good luck!

Andre

[Pat Dilling]

GEEZ PAT! I hope you resolve this issue. as I know you have been having major issues with this. You have gone above and beyond what is asked and still having original problems with.

I on the other hand, just been dealing with trees falling on my boat.

Good luck!

Andre

Oh wow! That's no good, hope insurance takes care of you promptly. Do you have fiberglass damage?

[CatFan]

Try it without the Stealth. Any such charge on the run system prevents or delays the cranking battery from fully charging.

[Pat Dilling]

I'll try that.
One more thing, voltage was down to 11.4 when it wouldn't start. After I jumped it ran about 5 to 8 minutes back to the ramp, voltage was showing 13. That's on the Stealth gauge. Drove 90 minutes back home, checked again and it was still 13 volts. This time on my multimeter.

[CatFan]

I'll try that.
One more thing, voltage was down to 11.4 when it wouldn't start. After I jumped it ran about 5 to 8 minutes back to the ramp, voltage was showing 13. That's on the Stealth gauge. Drove 90 minutes back home, checked again and it was still 13 volts. This time on my multimeter.

Alternator should be putting out about 14.6V with a battery that discharged. It’s unable to supply enough current to raise the voltage that high. The Stealth sees 13V and treats the battery as charged and diverts power to the trolling batteries.

[jg379]

Could be the alternator on the motor. After you run you boat see if your alternator is getting very hot. It could have a short. I had a buddy who's boat was eating batteries and we pulled the cowling and the alternator was glowing red after a long run

[BMCD]

I'd suspect an alternator or the charger, not wiring.

[Pat Dilling]

For testing purposes, I disconnected the Stealth 1 positive lead to the cranking battery and plugged in the NOCO charger. Charging light for crank battery came on and stayed on for at least 1.5 hours. Went fishing today. Did a couple long stretches without firing the big motor. Cranking Battery never went below 12.2. Will continue testing.

[KCLOST]

I have had the same issue with two other Interstate 31 AGM. I am now on my 3rd battery for my 2021 Z20. I believe my dealer found the cause of the problem. It turned out to be the charger was overcharging or putting to much voltage to the starting battery (for an AGM). It works fine for several months but after about a season of fishing it eventually kills the battery. My charger was a four bank Genious but did not have the settings to select the type of battery that is on each bank, my new charger does. So far, so good but we are too early in the process to see if this is a long term fix. This was all covered under warranty, new battery and charger.

[Pat Dilling]

I have had the same issue with two other Interstate 31 AGM. I am now on my 3rd battery for my 2021 Z20. I believe my dealer found the cause of the problem. It turned out to be the charger was overcharging or putting to much voltage to the starting battery (for an AGM). It works fine for several months but after about a season of fishing it eventually kills the battery. My charger was a four bank Genious but did not have the settings to select the type of battery that is on each bank, my new charger does. So far, so good but we are too early in the process to see if this is a long term fix.

That is good information to know. How did the dealer make that determintation? And what did you replace the charger with? Was it a warranty or purchase?
Thanks!!

[KCLOST]

That is good information to know. How did the dealer make that determintation? And what did you replace the charger with? Was it a warranty or purchase?
Thanks!!

Sorry for the late response. He simply checked the voltage on the charging leads while it was charging. After the charger was plugged in, after a little bit of time the voltage went up to 16V and would stay there until it was fully charged. I believe most AGM batteries should not be charged by more than 14.8V (I have read). Over time this is his belief as to why I have gone through two batteries in two years. I will add, that I had never had any issues with the batteries going dead on me, except when the battery started going bad due to this problem.

Good Luck!

[pitbully71]

I went through the same issues when I added Livescope. First Group 31 Interstate lasted 1 year. Had to replace it after being stranded on the lake while on vacation after a long day on the water. Replaced it with another big Interstate, which promptly lasted another year. This winter I bit the bullet and picked up an Iconic 125Ah Lithium. Fished for 8+ hours one day last week while in Florida, battery was at 92% after running 3 graphs+Livescope all day.

[bassfisher444]

Interstate batteries not lasting more than a few months to a year is pretty common. I would also remove the stealth charger and only charge the cranking battery with the outboard. You shouldn't need to charge your trolling motor batteries during a day of fishing, unless they are Interstates too then they are probably weak and going out as well.

[pdcjohnson]

My interstates are 2 years old well maintained and I’m already telling myself they won’t make it another season. I like my nitro but have always known those batteries are ticking time bombs and i can’t wait to get them out of my boat, my brothers interstates only lasted one season.

[Pat Dilling]

Sorry for the late response. He simply checked the voltage on the charging leads while it was charging. After the charger was plugged in, after a little bit of time the voltage went up to 16V and would stay there until it was fully charged. I believe most AGM batteries should not be charged by more than 14.8V (I have read). Over time this is his belief as to why I have gone through two batteries in two years. I will add, that I had never had any issues with the batteries going dead on me, except when the battery started going bad due to this problem.

Good Luck!

Thanks for that info. I have done the same test and the Genius was charging at 14.4. I have not checked after a period of time. Once it indicates a full charge it shows 13.3. I tried an experiment disconnecting the Stealth while I charged with the Genius. I left it it unhooked for a trip and had no problems. Voltage stayed at 12.2 or more. However I was moving around with the big motor more often than before. I hooked the Stealth back up and everything worked as it should on the next two trips. But again, I was not going for excessive periods of time with out running the big motor. Voltage never dropped below 12.2. So, for now I am remaining nervous but leaving it as is. Will make a point of running the big motor more often. Not the solution I want but will do for now.

PS: Now that Mercury has given the OK for qualified Litium cranking batteries, that will be the eventual next step.

[CatFan]

Thanks for that info. I have done the same test and the Genius was charging at 14.4. I have not checked after a period of time. Once it indicates a full charge it shows 13.3. I tried an experiment disconnecting the Stealth while I charged with the Genius. I left it it unhooked for a trip and had no problems. Voltage stayed at 12.2 or more. However I was moving around with the big motor more often than before. I hooked the Stealth back up and everything worked as it should on the next two trips. But again, I was not going for excessive periods of time with out running the big motor. Voltage never dropped below 12.2. So, for now I am remaining nervous but leaving it as is. Will make a point of running the big motor more often. Not the solution I want but will do for now.

PS: Now that Mercury has given the OK for qualified Litium cranking batteries, that will be the eventual next step.

12.2V is not a good reading. Nearly dead. How are you measuring?

[Mcjenson]

I know its painful, but going to a lithium for a cranking battery was probably one of my best purchases. Especially with bluetooth, being able to see exactly where your charge level is at is great.

[KCLOST]

12.2V is not a good reading. Nearly dead. How are you measuring?

My bet his he is measuring from his Garmin unit. Mine normally will drop to 12.2-12.1 if run 3 units for a few hours without running the motor. After running the motor it will read 13v or more, and that is with 20 ft of wires from the battery to the unit.

[Pat Dilling]

I am measuring off my Humminbird units, and the seperate Stealth Voltage gauge I installed. The gauge is measuring from the fuse panel in the driver console. There is a a couple 10ths drop from the actual battery. You are correct, after running the motor for a while, it is back up to 13.1.