Boat Battery Question

[STILLNOFISH]

I have been having problems with my on board charger and am looking at using a trickle charger instead. I currently have 2 twelve volt batteries hooked up to a charger so that all i need to do is plug it in, however I think this charger is frying my betteries the last few year. My question I have is, can I replace my two batteries and leave the wiring the exact same, but instead of plugging in the on board charger I put a trickle charger on each new battery instead? I am unsure on what cord goes to the on board charger, so instead of messing up the current wiring I was hoping I could just put a trickle charger on each of the new batteries and forget about the one on board one. I hope I explained my problem O.K I appreciate any and all advice. Thanks

[Dave]

First, what are your batteries for? If trolling batteries, are they hooked up in 12 volt parallel (+ to + and - to -) or 24 volt series (1st battery + to second battery -)?

Or, are you talking, one starting battery and two trolling batteries or one starter and one trolling?

Second, if your batteries are a few years old, they just may be getting worn out and seem like the charger is frying your batteries. Why do you think the charger is frying the batteries?

Third, a two output on board charger will have two wires going to each battery from the onboard charger, a positive and a negative.

Let's start with these questions and go from there.

[STILLNOFISH]

Dave, Thanks for getting back to me. Sorry for the general information I supplied.

These batteries are for the trolling motor. I am unsure how they are wired ( I'm really dumb when it comes to these things) but I do know that they both are used at the same time taking a little juice from each when operating the trolling motor. The reason I think my charger is not working, is the light is always green when I plug it in and I know the batteries are dead. This will also be my third time in four years replacing the batteries. My boat/starting battery has been good for 5 years. I hope this help. Once again, any and all information is appreciated. Thanks

[Chris Haley]

Stillnofish

Let's try this. Take masking tape and mark all the wires while they are on the batteries now. Such as + on battery one, - one battery one and + on battery two and - on battery two. This way you can take all wires off. After you have all the wires off, find the on board charger wires. If it's a two bank there should be four. Now seperate these for the two banks, by making sure you have the + and - for each bank. They will be marked with either red and black for the + and - plus either a number one or two, or they could have another color to indicate the different banks.

My thought here is that maybe you have your charger wires crossed up. Either two +'s on one battery, or a + from bank with the - from the other.

What trolling motor are you running?? Is it a 24 volt or 12??

[STILLNOFISH]

Chris Haley,

Thanks fo the feedback. I am getting my boat fitted for a cover, so it might be a few days to look at the batteries. I like your idea and will do just as you say. I will post how the batteries are currently set up. I believe I run a 24 volt trolling motor. I know it is a 55# minnkota. I'm pretty sure there are a few laughs out there based on my responses, believe me, my wife tells me to keep a desk job. Thanks again for the help.

[Dave]

I just searched a previous post from you, SNF, and you stated you have a 24 volt system. If that's the case, you should have battery #1 positive (+) connected to battery #2 negative (-). And, battery #1 negative will go to the trolling motor negative as well as battery #2's positive to the positive of the trolling motor. These will be large diameter wires.

Smaller wires will be running from the onboard charger to each battery. To make sure you don't damage the onboard charger from voltage feedback, I would disconnect the onboard charger wires and then use your trickle charger to charge each trolling motor battery. You do not have to disconnect the large wires connecting the batteries.

PS....what kind of onboard charger do you have? Chris may be on to something about them not being connected correctly; thus no charging. A lot of questions to answer but we'll get it straight someday

[STILLNOFISH]

Dave,

That sounds just like my set up. I will check to make sure, but this sounds very familiar. I was hoping I could disconnect the smaller wires and use the trickle charger, which you say is o.k. I will still report how the wiring is, incase Chris Haley is correct and the on board charger is wired incorrectly. This is truly a great site and thanks for the help.

[blakjack23]

"I know it is a 55# minnkota"

Do they make 24V 55# trollers? I had a 55# minnkota and I had always assumed 55# was the largest 12v you can get. Anything bigger then 55 and you jump to 24V???? Maybe I am wrong.

[Dave]

Blakjack may be correct. I don't know about older motors but I looked at the motor selection guide online for Minnkota and all 55#-thrust are 12 volt. I guess we'll need to hear back from SNF on how his is connected to know more.

[BIG DS]

I think you are right on the 55# being a 12 volt. The 65# is the biggest 12 volt and is also available in 24 volt. A lot of boat dealers will install 2 batteries and run them in parallel with 12 volt systems so that the batteries last longer. The reason behind this is that with the smaller trolling motors, you are more apt to run them at WOT in windy conditions. That is why those of us that sell trolling motors are usually trying to sell the buyers one size bigger than they think they need. Not to make more money, but with the bigger motor, the batteries will last longer because you run them slower. At slower speeds the Minn-Kotas are running on the maximizer system. At WOT they are direct to the battery. Anyway...the on board chargers don't often go bad, even if it is hooked up wrong. They have protection circuits in them. I would expect that the charger is hooked up to the batteries wrong, and that the reason you have went through so many batteries is that they were killed from sitting dead rather than being overcharged. A battery with no charge in it will freeze quicker in cold weather subjecting it to internal damage. I would strongly suggest taking your boat to a qualified proffessional to have them look at the wiring. Having wiring hooked up to a battery wrong is a good way to cause an electrical fire or worse. Take this seriously and if you have any question in your mind what you are doing, let someone else. It is cheaper to pay a mechanic then replace your boat.

[Satchmo]

The Minnkota 55 PD is a 12 volt motor. I have a couple other questions. Does your boat use a 2 or 4 wire system for hooking up the trolling motor batteries, what brand of charger is it, and how do you store the boat in the winter. All are factors in what could be going on with your system. You can test the charger output with a meter to find out if both banks are working properly. What brand/style/color of trolling motor plug is on the motor itself. If you need help call me when you get the boat back and maybe I can talk you through a system check. It may be an easy fix.

[STILLNOFISH]

Thanks once again guys for the help. I see why my wife wants me to stay behing a desk, I can't even figure out if my trolling motor is a twelve or 24 volt. I guess I thought that since I have two batteries for my trolling motor I must have a 24 volt. It does make sense now to have two batteries for a 12 volt as well. My boat is stored in my garage and I plug the battery charger in periodically. I have a green and a red light on my charger and for the last two years I have only seen the green light on and never the red. I will look at the wiring and try to explain were they are going. I will also look at the brand and call an expert if need be. It has probably been awhile since you guys have experienced such rediculous questions and responses from a guy like me Thanks again for the help.

[ChuckN]

Quote:

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The reason I think my charger is not working, is the light is always green when I plug it in and I know the batteries are dead.

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Have you checked the in-line fuse that is between the charger and the battery? Same symptom happened to my boat after I bought it (used).

You say the batteries are dead, and the in-board charger does not work.. Have you tried to charge each battery with another charger? Did the batteries charge, and hold a charge?

If you don't have the operator's manual for the in-board charger, I would get it off the web from the manufacturer. Or contact the manufacturer and they can help.

[STILLNOFISH]

ChuckN

I was hoping to put the trickle charger on them to see if they would charge, but was needing to know what wires I should disconnect from the two batteries. It appears the two little ones would need to be disconnected and leave the rest the same. I am going to take a close look at the set-up so I can give you guys a better understanding in what I have. Boy, I never knew I was so clueless when it comes to these things. I'm sure my 5 month old son could figure this out before I can

[BIG DS]

Wiring can be very confusing, don't feel bad. I would reccomend un-hooking all the wires and charging one battery at a time. Just tape the wires together for each post and label them as mentioned earlier. It would be a good idea to trace the wires back to your onboard charger and pull them out of the way. Then while you are charging your batteries with your trickle charger, you can check over the onboard charger for a in-line fuse that is blown as mentionen and check for power at the leads when it is plugged in.

[Chris Haley]

You may be confused on what voltage trolling motor you have, but it's wired correctly for the motor or you would have burned up your motor.

The problem is going to be with the way your charger is wired, or the charger is bad.

[STILLNOFISH]

I will look at the wires and tape them the way explained. I can then explain to you guys better what wires are going were. One last question about this in line fuse. How would one tell if it is blown? I assume I would take the batteries out after taping them and labeling them correctly, then look over the onboard charger. Will it be pretty obvious if it is blown? If the green light comes on when plugged in could this fuse still be blown? Thanks for the help. SATCHMO I may end up giving you a call. Thanks

[ChuckN]

The fuse should be in a small capsule on the wire. If I recall, my green light came on when I discovered a blown fuse. The red light would not come on. I have a Guest charger. I would inspect it anyways, can't hurt.

[BIG DS]

The green light is only indicating if the battery is taking a charge. If the fuse is blown, there will be no draw on the charger and the light will remain green. If the fuse is blown you will be able to see it plainly.

[Chris Haley]

Any update on this problem??