36 volt XI5 batteries going dead

[Super D]

36 volt XI5 with brand new Duracell agm31 batteries(3) will only last 6-7 hours. I am running a 521 ranger and pulling crankbaits at 1.8 mph avg. which I am running it pretty constantly. Is this all I can expect to get or does something sound wrong? Went to the 36 volt so I would hopefully end this problem. Thanks in advance for any advise

[vic n]

Does each battery have it's own charger, including the crank battery? If not, they have trouble getting charged. If you have one bad battery, the others will act the same, so you might charge them up and take them in for a test.

[Super D]

Minn Kota 4 bank charger, 3 brand new agm31 batteries, shows green in the morning and runs good in the morning, just goes dead

[Redge]

I think something sounds wrong. I have a 21' skeeter with a 24v terrova, can pull all day 1.8-2.0 mph. Would think the boats are similar in weight.
I could be wrong easily. Some of the smart guys will be along shortly. I would think the 36V would last way longer. Hopefully we will both learn something.

[crappielimits]

Either one of your batteries is going bad or getting water in foot of trolling motor. What size wire is run to your trolling motor and length of wire? Have you checked batteries? I know a Minnkota would go at least twice this long if everything is working properly. Not sure on Motorguide but assume it's close.

[Super D]

Either one of your batteries is going bad or getting water in foot of trolling motor. What size wire is run to your trolling motor and length of wire? Have you checked batteries? I know a Minnkota would go at least twice this long if everything is working properly. Not sure on Motorguide but assume it's close.

Found one battery not charging but to 25% after a night time charge. It would charge fully or at least say it was fully charged after a week on the charger Gonna swap that battery and see if it helps, just annoying because the batteries are only 2 weeks old. Wiring s the same as what came on the boat new.

[vic n]

Another possibility might be that one bank on your charger may not be working.

[Cray]

Any time you have one bad in a bank it will suck the charge out of the other ones. Could have been bad from the factory.

[Super D]

Checked all 3 batteries with a volt meter today, after half a day fishing yesterday and no charge on them, two were just above 12, and the one I figured could be bad was at 11.4, after plugging the charger in the two went to 12.4 pretty quick and the suspected bad one went to around 12. Maybe I should have monitored them for a few more minutes but I'm hoping that one battery may be the cause of my problem?

[CatFan]

Checked all 3 batteries with a volt meter today, after half a day fishing yesterday and no charge on them, two were just above 12, and the one I figured could be bad was at 11.4, after plugging the charger in the two went to 12.4 pretty quick and the suspected bad one went to around 12. Maybe I should have monitored them for a few more minutes but I'm hoping that one battery may be the cause of my problem?

Probably. 11.4V is a long way below 12V in state of charge, but both indicate very deeply depleted batteries. 12V is 75% discharged, and 11.4V is below 100% discharged on East Penn's chart.

Your batteries should be getting to 12.8V after they have been fully charged and allowed to sit a few hours with the charger off. I'm suspicious that you may have a charger issue. What kind of charger do you have?