On board charger

Looking to add a 3 bank on board charger to my boat. There are a bunch of options looking for any recommendations. It would be a 24v trolling motor and a cranking battery.
Thanks
Blake

I put some research in and this is the best bang for the buck I found.

https://www.cabelas.com/product/PROFESSIONAL-MARINER-PROSPORT/3072542.uts?slotId=1

5amp per bank is pretty low and it will take a while to charge a low battery. 10 amp will barely charge mine overnight. If you just fish weekends the 5amp will probably work for ya.

I’m sure there are many good brands, but I use Dual Pro charges.

I have the Minnekota 10 amp per bank. It has worked well for the past 5 – 6 years. The foot print was bigger than the old charger. It was a challenge to mount in the same spot.

@ Joe Scegura, Your 10 amp will barely charge yours overnight?

Geez Joe, I’m not debating what you said, I either have a much better charger than yours or your batteries are several times larger in capacity than mine.

Maybe I need to take a deeper look into my batteries after an overnight charge. I have 2 different chargers in my boat, a very old “Pro Logic” 3 bank 10 amp/bank and a Minnkota 10 amp single bank attached to 4 Group Size 31DP Interstate AGMs.

I would stay away from pro mariner chargers. I had 2 go bad within a year.
I have had minn Kota and dual pro since without issue.
Go for at least 10 amps per bank.

Here is some approximate battery capacity info:
Group 27 85-105 Amp hours 12 volts
Group 31 95-125 Amp hours 12 volts

if you ran your battery to completely dead (which you would never do, it would shorten the battery life significantly). Take the amp hour capacity and divide it by the charging current. It would take between 9.5 and 12.5 hours to completely recharge a Group 31 battery with a 10 amp charger or between 19 and 25 hours for a 5 amp charger.

These are not perfect but a good gauge. If your trolling motor is still running at the end of the day you have probably only discharged your battery to about half, so you will have to replace half of the amp hours.

According to Minn Kota a 80lb thrust trolling motor draws about 56 amps at full speed (max draw). So, at full speed your trolling motor will use up 56 amps capacity from each of your 12 volt batteries in your 24 volt system. At full speed your grp 31 batteries will last somewhere near 2 to 3 hours.

now that you have the math…fish on…

Joe Scegura wrote:

5amp per bank is pretty low and it will take a while to charge a low battery. 10 amp will barely charge mine overnight. If you just fish weekends the 5amp will probably work for ya.

Same setup as you. my boat came with the 5amp/bank Minnkota. Have power at the dock and I’m good so far. That said, I would absolutely move up to 10amp/bank right out of the gate if I had a choice. Still considering it just because it’s a better setup but can’t justify the money right now.

Denny O wrote:

@ Joe Scegura, Your 10 amp will barely charge yours overnight?

Geez Joe, I’m not debating what you said, I either have a much better charger than yours or your batteries are several times larger in capacity than mine.

Maybe I need to take a deeper look into my batteries after an overnight charge. I have 2 different chargers in my boat, a very old “Pro Logic” 3 bank 10 amp/bank and a Minnkota 10 amp single bank attached to 4 Group Size 31DP Interstate AGMs.

I run 31 group batteries and after a hard day using the trolling motor it will not charge my batteries by the morning. It’s just math… not an opinion.

A 31 group batter has around 100-125 AH. With low batteries and a 10 amp charger you are looking at 8-10 hours to charge it. Pretty simple, but please correct me if I’m wrong though.

EDIT: I didn’t read your post dhshannson. Well put and your numbers look pretty spot on. It takes a lot of time and amps to replace the ones you use during the day. Thanks