On board battery charger....no idea how it works

[tacklejunkie]

I bought a used but bigger boat and I noticed it has on of those on board battery chargers. I have no experience with this. I'm assuming this charges both trolling motor batteries. How do I hook it up tothe batteries and use it? I have no idea how tis works

[DooWap]

If the charger is already hooked up to the trolling motor batteries, all you should have to do is plug the charger into the wall. There should be an LED indicator that says when the batteries are charged. Otherwise, there should be a + and - lead off of each bank of the charger. Connect each bank to each of your batteries and then plug it in and let it charge.

[h8go4s]

Some details would help. Brand name, model number. Is it a 1-bank, 2-bank or 3-bank? How many batteries are in your boat, and what is each one used for? Do you have a 12-volt, 24-volt or 36-volt trolling motor?

[BobT]

If the charger is already hooked up to the trolling motor batteries, all you should have to do is plug the charger into the wall. There should be an LED indicator that says when the batteries are charged. Otherwise, there should be a + and - lead off of each bank of the charger. Connect each bank to each of your batteries and then plug it in and let it charge.

It is important to know couple extra details.

1. Some chargers have specific leads for the starting battery vs deep cycle batteries. The preferred charge sequence is different for these two types of batteries.

2. Some chargers also need to be configured for the type of batteries used. Again, the charge sequence and voltage levels used are different depending on the battery type used.

3. Some chargers require that all leads are connected to a battery.

For example, in my system I have one starting battery and one deep cycle battery for my bow mount trolling motor. Both batteries are wet cell type batteries. I installed a 3-bank charger in case I decided to add another deep cycle down the road. On my charger I had to choose my battery type, wet cell or gel pack. My charger had one specific bank for the starting battery and the other two banks for the deep cycle batteries. The manual required that I do not leave unconnected bank leads so it instructed that I connect both pairs of deep cycle leads to the one deep cycle battery I have. My charger is designed to a maximum current output but it can apply that total maximum to just one battery if the others are fully charged. Open leads probably confuse the system into thinking there is a defective battery.