Battery switches

[The Mia Fay]

I have a Yamaha 2021 , 252S. When I go out for the day I have to leave the two red battery switches on house and start. I leave the yellow one off if I’m using the radio etc will this run down both batteries.I tried to shut off the start switch but nothing will work. is this normal

 

[FredB32]

Completely normal, from my experience (2017 212x). The yellow switch is only to be used/turned on in emergencies if for some reason your starter battery gets drained - it parallels both batteries to provide the juice to start the boat so you're not stranded. When you're moving and/or just floating, both batteries should be on for accessories to work, but the boat will run off the house battery, leaving the starting battery charged.

 

[Judge]

It is a great feature. I have a motorhome and you have house and chassis batteries. It also has an emergency start switch, which ties the two battery banks together to get enough boost to start the engine.

But question for the OP..... when you turned the start battery switch to OFF, the radio wouldn't work? I would think the radio would still work as long as the house battery switch was set to ON.

 

[FredB32]

It is a great feature. I have a motorhome and you have house and chassis batteries. It also has an emergency start switch, which ties the two battery banks together to get enough boost to start the engine.

But question for the OP..... when you turned the start battery switch to OFF, the radio wouldn't work? I would think the radio would still work as long as the house battery switch was set to ON.

It's the same on my boat as OP's - my guess is that's normal, but I could be wrong. The manual doesn't say much (anything) about "float mode", just this little blurb about "normal operation":

 

[Judge]

It's the same on my boat as OP's - my guess is that's normal, but I could be wrong. The manual doesn't say much (anything) about "float mode", just this little blurb about "normal operation":

View attachment 184876

Thanks!

It sounds like only the bilge pump and lights are the only things in the house battery circuit. I would have thought the Connext screen would have been on the house battery too because of the Float Mode and radio...... but the bilge pump and nav lights would be considered critical systems such that you would not want the battery to drain down so they would not work from from Float Mode and radio usage.

Probably another reason they added parallel switch. If you are out floating all day and the screen is in Float Mode with the radio going, there could be a chance the starting battery would get drained enough that the it may need a boost from the house batteries to start the engines.

 

[FredB32]

Thanks!

It sounds like only the bilge pump and lights are the only things in the house battery circuit. I would have thought the Connext screen would have been on the house battery too because of the Float Mode and radio...... but the bilge pump and nav lights would be considered critical systems such that you would not want the battery to drain down so they would not work from from Float Mode and radio usage.

Probably another reason they added parallel switch. If you are out floating all day and the screen is in Float Mode with the radio going, there could be a chance the starting battery would get drained enough that the it may need a boost from the house batteries to start the engines.

I can't honestly say it's the correct way, but that's the way mine is wired. From my understanding, the starting battery should be essentially wired to only the engines for starting purposes. I've found several threads that seem to indicate this is the way it works for most people (could just be dealers wiring the batteries wrong? Seems doubtful). I found a couple that said you can turn the starter off, leave the house on, and pushing buttons on the controller for the Connext should boot that system up with just the house battery turned on...but I haven't tried that yet.

 

[Judge]

I may end up ordering the Service Manual. It will have the schematics and the way Yamaha intended it to be wired.

 

[FredB32]

I may end up ordering the Service Manual. It will have the schematics and the way Yamaha intended it to be wired.

Not a terrible idea - I'm on the hunt for a decently-priced option for my boat as well, but it's looking like I'll just have to fork over the $90-100 they want.

 

[212s]

The newer boats with the MFD screens made by Ennovation may act differently with the switch positions, but the wiring should be the same - the start battery should be isolated from the house electronics, like the stereo while floating. It's possible something was crossed with the battery wiring, but that's the way it is supposed to work. If my start switch is off, my Connext alarms that there's a dead 0-volt start battery, but the rest of the electronics work normally. The newer screens may simply be blocking the house system unless a start is detected...but that's overkill on the design end.

Have you looked at the wiring at the batteries? The house and start positive cables should be clearly marked and easy to ensure proper connection.