Trolling motor batteries

[catchersrock]

So, when I rigged out my 2020 228, I put a 24 volt trolling motor on it. Several reasons, cost, 4 total batteries on the boat, one battery charger, cost. Overall, the added trolling motor cost, added battery, and, added charger was more than I thought the difference was worth to go to a 36v.

It has been fine, fish all day, do whatever I needed, no problems. Until yesterday. Sometimes I troll swimming plugs with the trolling motor. Yesterday, half of my runs were into a substantial head wind. Had to run the trolling motor to 7 to keep minimum speeds. 2 hours of that and the batteries were spent. 

The batteries I have in the boat are PF-24DC, CCA - 550, MCA - 685, RC - 140.

I can fit bigger batteries in the space allowed. 

What do you guys recommend? 

[Juan]

Are you sure they were fully charged and your charger is putting a full charge to the batteries? If that's the first time they failed they might be losing performance with a lot of discharge-charge cycles and it's time to replace them but I'd bet they weren't fully charged. If you do any running between fishing spots, you might do what I did and install an on the fly alternator charger that charges the trolling motor batteries when the big motor is running. I've yet to kill the batteries.

[catchersrock]

Thanks Juan. Which alternator did you install and are you happy with it?

[Juan]

Apr 26, 2021 19:31:20 GMT -6 catchersrock said:

Thanks Juan. Which alternator did you install and are you happy with it?

I've got the Minn Kota MK-2-DC (2 Bank) DC Alternator Charger: mk.factoryoutletstore.com/details/33550/minn-kota-mk-2-dc-dual-bank-dc-alternator-charger.html

I like them. I put one in my bass boat too. They're easy to install and keep the trolling motor batteries charged when running the big motor so they won't help much if you fish in one spot all day.

[freezerfiller]

I've got 27 series batteries for mine and they run hard all day. I did have an issue one time, but it turned out my charger connection was corroded and the charger wasn't charging like it was supposed to. The minn kota charger Juan listed is good for 20 amps. Here's one that's good for 100 amps, but I don't know what your alternator puts out, it might not be worth it. yandina.com/troll12X24info.htm

[Juan]

I'm no expert on batteries but I've always heard that a slow charge is better than a fast charge. I looked at the chargers freezerfiller mentioned and wasn't convinced that was the best option since almost all of the trolling motor chargers I had looked at charged at rates from 5 to 15 amps. I wasn't sure I wanted all of the alternator's power charging my trolling motor batteries so elected to go with the Minn Kota since trolling motors is what they do.
As I said, I haven't drained my batteries even after a full day of running them hard and I'm convinced the alternator charger plays a part in that but I do have larger group size batteries and that may be the difference.