Thread: 36 volt XI5 batteries going dead

It's a min Kota charger not even a year old, started to pop the foot off to check for water tonight and found some line in there, in the meantime, charging the batteries up and gonna check voltage, hopefully that was the problem, sounds stupid I know, but don't overlook the smallest things. I'll be posting my results when they are confirmed. I still have my doubts about 1 of the batteries though

Originally Posted by Super D

It's a min Kota charger not even a year old, started to pop the foot off to check for water tonight and found some line in there, in the meantime, charging the batteries up and gonna check voltage, hopefully that was the problem, sounds stupid I know, but don't overlook the smallest things.

Even with line on there, the batteries should have drawn down evenly. You most likely have a charger or battery problem.

You can also swap the bad battery bank on the charger with one of the other batteries. If the problem moves to the other battery, then your charger is bad. If the problem stays with the same battery, your battery is bad.

Since the battery has been discharged to an excessive degree, it could be damaged and not recoverable. The AGM batteries can be discharged a little more than lead acid without causing damaged, but it does sound like the one battery may have a bad cell..........Swapping them around is a good idea, just be careful you don't ruin another battery.

I have now swapped the battery to a different bank on the charger, and after disconnecting each battery from the series, the charger will go from a solid red on top to a 25 percent yellow normal charging solid light on all 3 agm battery banks. Before I unplugged to switch the battery charger around, 2 of the three were showing full charge and all 3 batteries tested at about 13.5 with the charger on them. Trying to get ahold of minn Kota service center but they are having phone difficulties. Any new ideas?

Originally Posted by Super D

I have now swapped the battery to a different bank on the charger, and after disconnecting each battery from the series, the charger will go from a solid red on top to a 25 percent yellow normal charging solid light on all 3 agm battery banks. Before I unplugged to switch the battery charger around, 2 of the three were showing full charge and all 3 batteries tested at about 13.5 with the charger on them. Trying to get ahold of minn Kota service center but they are having phone difficulties. Any new ideas?

Let them charge for at least 24 hours, then unplug the charger and let everything sit for 6-8 hours and measure the voltage on each battery again.

They charged 24 hours, unplugged, plugged in, same problem the charger was showing. Called Minn Kota, and they are sending me a new charger. Hopefully this fixes it

Got my new charger yesterday and before installing I checked voltage on all 4 batteries and all were right at 12.8ish after not seeing a charge in 6 days. Installed the new charger ad set each bank to battery type and it works like it should and showed full charge within matter of 30 minutes. Going out this weekend to see if I have any improvement>>>

I'm going in a different direction here; with battery issues solved, you are pulling a BIG boat with a lot of weight for a long time. I'd be shocked if everything mentioned about is taken care of that you are going to see a lot more time trolling before you discharge your batteries. You can trim your motor up to where the skeg is just below water level when you start trolling and should see and improvement.

A bass boat buddy of mine was trolling with me recently. The lake was choppy so I had the lower unit farther down in the water than I normally do when trolling. He asked me if it really made a difference? When I trimmed my motor up to its normal trolling height, I picked up 0.4-0.5 in boat speed over my normal 1.7. When the cruise control on my Terrova dropped the motor speed to get back to 1.7, I saw my motor setting drop from 4.5 to 3.5. Over the course of a long day trolling, that would mean several more minutes of trolling before battery discharge.

Originally Posted by mrdux

I'm going in a different direction here; with battery issues solved, you are pulling a BIG boat with a lot of weight for a long time. I'd be shocked if everything mentioned about is taken care of that you are going to see a lot more time trolling before you discharge your batteries. You can trim your motor up to where the skeg is just below water level when you start trolling and should see and improvement.

A bass boat buddy of mine was trolling with me recently. The lake was choppy so I had the lower unit farther down in the water than I normally do when trolling. He asked me if it really made a difference? When I trimmed my motor up to its normal trolling height, I picked up 0.4-0.5 in boat speed over my normal 1.7. When the cruise control on my Terrova dropped the motor speed to get back to 1.7, I saw my motor setting drop from 4.5 to 3.5. Over the course of a long day trolling, that would mean several more minutes of trolling before battery discharge.

This is is the kind of answer I was looking for, however at least 95% of the time I trim my motor up, just as you stated. I know guys that pull big pontoons around with 36 volt trolling motors too, but hopefully I will figure something out.