Batteries

Hello. I recently purchased a 1999 240 Sundancer. Enjoying it very much. I have a question about the batteries. I have the switch with positions for battery 1, battery 2, or Both. However, in the engine compartment there are three batteries. I assume a previous owner added a battery. Not sure why. I don’t know a lot about batteries, but it appears these are wired on a “parallel” manner which apparently might increase run-time? Mainly, i’m Wondering how the third battery interacts with the battery switch e.g. is the third battery utilized only when the switch is in the Both position? Will the alternator charge all of the batteries? What is the most effective way to take advantage of having this extra battery if I’m away from shore power for a few days? Thanks for any help!

Most likely, your cranking battery is Battery 1 on the switch and the other 2 are wired in parallel and are on Battery 2. Need to figure that out to be sure. The two wired in parallel are your house batteries and give you twice the run time. They will act and you handle them like they were just one big battery. Fully charged and in good health, you should be able to stay on the hook for several days. Always change to the house batteries when you shut your engine down and save the cranking battery for nothing but started. When you move the switch to “Both” you have the power of all three batteries.

Bennett

Thanks, Bennet! That would make sense. Except, I can start the boat in either switch position 1 or 2. If a previous owner had dedicated battery 1 as the “cranking” battery, I shouldn’t be able to start the boat in switch position 2, should I?

Larry33 said:

Except, I can start the boat in either switch position 1 or 2

Click to expand...

This would be a properly wired setup. The dedication comes manually on your part. You crank on 1 and anchor on 2.

Wylie_Tunes said:

This would be a properly wired setup. The dedication comes manually on your part. You crank on 1 and anchor on 2.

Click to expand...

Yup!!