Pontoon Boat & Deck Boat Forum

So, this summer (4 months) we will be at a lake with no power at the dock. I will need to replenish our 2 group 24 batteries for the trolling motor. So far it looks like my options are:

Solar battery charger panels
Gas generator hooked up to my already installed battery charger
Hauling batteries out every couple days to campsite to charge
DC Charger that uses the engines generator power

I was reading last night about the DC Chargers. They look pretty interesting. After the boat battery is close to full charge, the excess power being generated from the engine will go to the trolling motor batteries. We will likely be running the boat engine anywhere from 10-30 minutes daily on average, with occasional 60-90 minute runs. I also don’t run the trolling motor much, probably won’t use more than 20% of the battery capacities at any given time.

I have a Yamaha 150, with a 35 amp max generator.

Is anyone using a DC Charger for their trolling motor batteries? I would like to know what to expect for recharge abilities. Will I have to use a conventional AC charger occasionally? I don’t mind taking the batteries out once a week or so to charge if needed, just don’t want to do it multiple times a week.

Thanks for any feedback.

Here’s an email camp,e of an on board DC Charger I’m looking at. I hope someone has one that can advise on its performance.

I've never seen one. Maybe someone will chime in that has. Welcome!

Thanks Craig. I first heard of these years ago being used in bass boats to charge TM batteries. Websites also recommend them for pontoon boats. Any boat with secondary batteries should benefit from it, but how much is the question. Someone must have them...

I'm going to be putting a 12V trolling motor on the bow of my pontoon this winter....My plan is to use a battery isolator like this http://www.perko.com/catalog/category/battery_switches/ I've used them in the past and they work great... My thoughts are that your motor will keep your batteries topped off...

OG-
The problem with your solution is that if you run your trolling motor a lot and your OB a little (or at lower RPM's), there's not enough time (or amps) coming from the OB motor alternator to recharge the trolling motor batteries. Although I have no experience with DC chargers, Steve7 seems to be on the right track.

Here's a good article I found on the subject

http://www.carolinasportsman.com/details.php?id=4594

I've never had a problem...then again, I have never used an electric motor for sustained trolling, only for maintaining position for short periods of time, or maintaining a certain distance from the shoreline when fishing for crappie or bass....for sustained trolling, I've always found a trolling plate to be the best solution.

One thing I used to do with my little Valco, was to let the wind blow me along and use the electric motor to keep my speed in check. I don't know if it'll work with my pontoon boat, but I'm gonna give it a shot...

Retired OG, the battery isolator is a good idea and a possibility. It would mean me coordinating the flows manually though.

Steve, I think I will be good with the DC Alternator, with the occasional use of a 2000 W Honda generator. Like Retired OG, I am not on the TM much when I do use it, and will vary my boat motor usage with short and longer trips, hopefully keeping the batteries fairly high.

There appears to be maybe another alternative choice available to you since you're running a Yamaha 150 or larger. 150"s and up come with an auxiliary battery charging port installed. All a person needs is to do is acquire the wiring harness (http://www.partspak.com/productcart/pc/ ... uct=239499) and wire it in. This should reduce voltage loss to nothing simply because there isn't a charger inline consuming any power doing it's job it all goes straight to the batteries when the motor is running. As far as cost it appears to be about the same with careful shopping anyway.

Info is out there but a bit sketchy to find. Thread from another forum that may be helpful. https://www.thehulltruth.com/sim-yamaha ... -lead.html

I have a dual bank charger on my boat. Don't remember the brand but it has worked for 5 years. One thing I do is use a timer, it only runs an hour a day

Thanks guys. That’s interesting that th outboard may have an alternative hookup for charging. I’ll look into that more.

I cannot speak to trolling motors but I have a solar panel hooked up to the battery for my lift and never once had an issue -- even holiday weekends with a lot of use.

With a solar panel, is a charge controller required to prevent overcharging? With a small panel, is it necessary? I did find this.

https://www.amazon.com/yueton-Controlle ... controller

It looks pretty simple. 2 solar panel connections, 2 battery connections, and 2 connections to hook up a load for shedding excess power.

I'm also aware of those chargers but my knee jerk opinion is that there is just not enough run time on the main engine to charge if the troll batts are used much (how much is much ??) Some of the really smart guys can use the formulas about all the watts, amps, amp hours and so on to get a better idea. What caught my attention is your use of the 24s and not 27s. I'm in the process of installing now and have been debating 24 vs 27. The 2 27s will only add another 8 lbs and a few more bucks. How the 24s working for you?? I will be using one of the smaller 24v motors (68 lb)

A typical Group 24 is rated around 75-85 amp hours.
A group 27 jumps to 95 to 105 ah.

Those ratings are based on draining the battery slowly from full to empty over 20 hours.
If you pull all of the power from the battery in something like 4-5 hours, you will get about 20% less. That's just the nature of the beast for flooded, gel and AGM batteries.

If your 80 ah was only drained by 20%, that would be about 16 amp hours. If your alternator can provide 20 amps to the trolling batteries, then a 50-60 minute run would be required to charge the battery. If you drained out half of the battery capacity, you would need a bit over 2 hours of running, etc. Keep in mind that some of the 35 amps from the alternator is required to run the engine!

My little 115 HP Yamaha can only produce about 15 amps of 12v DC. I have very, very large trolling motor batteries, so a shore charger is used. BUT, the alternator keeps them topped off while not being used. For remote use away from my dock, my Honda 2000 drives my 60 amp charger with ease.

Marc