dual battery use

[armstead]

I have a 03 Sundeck with dual batteries. I was wondering when I start the boat with both batteries should I leave it in the all/both battery position to recharge the batteries, or do I turn it to off and it charges the battery. It seems to leave the switch in on/both/all position, but I was sure the guy I bought the boat from said when I start the boat turn theswitch to off. This jsut does not seem right, not to mention my number one battery now needs charging becaeue it can;t start the boat by itself, whcih i use while sitting dead in the water listening to music.
Can someone clear this up before I hit the water this saturday.
Thanks in advance

 

[chuck1]

Never turn the switch to off when you have the engine running!!!
Start on both, When you drop anchor or are just hanging out listening to the tune switch to one battery so if you run it down you always have the other to start with.

 

[armstead]

Thank you, I was sure that was the way it was suppose be. I just hope I can get my #1 battery to charge back up!

 

[desperado]

Never turn the switch to off when you have the engine running!!!
Start on both, When you drop anchor or are just hanging out listening to the tune switch to one battery so if you run it down you always have the other to start with.

Yes, yes, yes,!!!!!!! FOR GOD'S SAKE DON'T TURN SWITCH TO OFF WITH ENGINE RUNNING!!!!!!

 

[Lazy Daze]

Well, it seems the "off" issue has been addressed!

Once you have the engine started - it is usually easier to do it on the "good" battery, then turn it to the "bad" battery. If the engine dies, start it on the good one, then switch to "both" for a bit. The you can turn it back to the bad one and charge it up. When possible, it's best to charge each individual battery by itself. It's OK to switch between 1-2-both with the engine running, but unless you have an alternator field disconnect wired in, never to "off" while engine is running. An AFD is not installed from the factory.

 

[Sundancer]

I agree with LD, we ran odd or even based on the calendar. So on an odd day, we would run the #1 battery. IF there was a problem, we'd switch to #2 knowing it was fully charged. If the batteries are of different vintage or one goes bad and you are charging via the "both" position you may never get a good charge on either battery. Depending on the battery type, you may have to run an hour or more to get a charge, more if you used a lot of juice. I would start and run that same battery to replensh the starting load. THEN I would switch to either 1 or 2 to give all the juice to ONE battery.

 

[JediJD]

It's OK to switch between 1-2-both with the engine running, but unless you have an alternator field disconnect wired in, never to "off" while engine is running. An AFD is not installed from the factory.

You are a trained professional, but I just wanted to confirm this. As a layman, it would seem that if the criticality is turning the switch "off" while the engines are running, those parameters are met, at least briefly, by turning the switch at all. As you move a selector switch between 1-2-both, the space between the selection is "off".

 

[Weave]

You are a trained professional, but I just wanted to confirm this. As a layman, it would seem that if the criticality is turning the switch "off" while the engines are running, those parameters are met, at least briefly, by turning the switch at all. As you move a selector switch between 1-2-both, the space between the selection is "off".

If I understand correctly, the switches have a make before break set-up to protect from frying the alternator....I am sure someone here can provide a better description though:thumbsup:

 

[Lazy Daze]

If I understand correctly, the switches have a make before break set-up to protect from frying the alternator....I am sure someone here can provide a better description though:thumbsup:

That is correct - couldn't of said it any better! In other words, there is a little bit of "overlap" when you switch from 1 to 2 or Both.

Good question, Jedi! :smt001

 

[JediJD]

Thank you for the amplification and explanation. I feel much better about switching now and the entire process makes MUCH more sense.

 

[RT 240SD]

Check the levels in your #1 battery. If it isn't holding a charge it may also be a bad battery... these things do happen

 

[jetjarv]

we had a car with a bad battery. unfortunately we only used the car once or twice a month and we just figured some computer was discharging our batt. so we kept jump-starting it. then the alt went out because the battery was bad. is switching the dual batt setup to off doing the same damage?