Do Outboards Charge Dual Accessory Batteries

[FinChaser]

Just bought a 2001 Marlin 300. I was looking over the original owners manual from Grady and noticed the the battery select switch schematic does not indicate that accessory batteries are connected to the engine batteries. This would mean that the outboards do not charge the accessory batteries. Is the only way to charge the accessory batteries to plug into shore power and run the charger?

 

[BobP]

I thought the Marlin has four individual batteries, that are paralelled into two banks, and each motor's 1/2both/off sw can choose between the two banks, which means the aux feed is the same as one of the motor's feed connections and there is only two banks not a 3rd bank used only for aux (?)

??

 

[FinChaser]

According to the schematics. There are two batteries wired to start the engines and there is a switch allowing the selection of either battery for each of the engines. There is two batteries wired in parallel wire to an on/off switch for the DC accessories. The batteries wired in parallel are completely isolated from the strting bateries.

This is just going off the schematic.

 

[BobP]

Then I have it wrong, so the two non motor batteries have to be supplied a charging source form one or both motors, as in motor aux charge feed option.

I guess there is no backup for aux feed batt.
Don't like that myself.

 

[BobP]

Have to wait for Marlin owner in the know to respond - plenty of them on forum.

 

[jtsailjt]

I don't know anything about how your batteries are wired except from reading the above posts, but if one isn't already installed, there's a thing called a battery combiner that I think would help in your situation. I installed one on a bigger boat I used to have and it worked flawlessly and my aux bank was always ready to go, and with no danger of me forgetting to deselect them and running down my starting battery. I realize that an aux bank isn't the top priority, but it's really bad for any battery to sit in a low charge state, so I think it's important to do everything you can to make sure they can easily get charged and stay that way until needed.

A battery combiner is an electronic device that closes the circuit between batteries when a certain preset voltage is present, but then opens it when the voltage falls below that level. So, for example, you could choose to set it at 13 volts and any time (during charging) your starting bank reached that level, you would also be charging your aux batteries. When you turn off the motor, they would stay combined until your voltage fell below 13 volts and then the circuit would open, ensuring you'll always have plenty of juice in your starting batteries to get your engines running again. There is also an override switch that allows you to close that circuit manually in the event you need your aux batteries to help start your engine. I think I paid a little over $100 for the one I bought about 5 years ago and it was easy to install myself.

 

[sickday]

My Marlin house batteries are charged by the engines. I believe its a factory set up similar to yours. 2 house and 2 engine. I almost never use the shore power to charge them unless I'm at the dock and drawing a lot of power with my spreader lights or overnighting in the slip.

I've drained them while on the water and recharged them while on the water in the same outing away from the dock. No problems yet

Hope this helps

 

[sickday]

The only issue you might struggle with, as I do, is that when you are plugged into shore power, you dont automatically run everything on the electric side. The microwave and the charger are about the only thing that runs electric. Everything else runs off of the batteries while the charger keeps the batteries charged. Even the fridge doesnt have the option to switch to from A/C to D/C. It would be nice to have an elctric fridge option while in the slip

And congrats on the purchase. Its an awsome boat.