Dual Battery Switch Set Up Question

kyle f

Chief Petty Officer
Joined
Sep 5, 2007
Messages
408
So, my new to me boat has a dual battery set up with a switch.

So, first question. What Switch position would I normally operate in.

Second, should I switch to just one if I am sitting in a cover runnign the radio?

Lasly, I am asking this because I have a 6 Channel Amp, and I am not sure how its power is hooked up to the batteries (Yet). However, Yesterday when I took it out for the first time by myself, the amp cut out most of its volume after about 5 minutes. Nothign noticibly hot or anything. Turn the system off, then back on after 5 minutes, and it does the same thing again.

When I got home, I decided to check it again. The Amp is near the battery switch so this time when it cut the volume ( You can still crank it and you can hear it, but it sounds like its at 2 on the volume control, but its at 32), I flipped the switch from "2" to "1" and it came back on for a while. Shut off again and all the interior lights dimmed... switched to all.... repeat.

I don't think its a battery issue, but I am not rulling it out. It starts just fine, and the volt gage was at a steady 14 the whole time I was in the water (But switch was on "2") the whole time.


Thanks for the help.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: Dual Battery Switch Set Up Question

I have about the same setup. What you are supposed to do, is set the switch to both at the dock and start the motor. Leave it on both while the motor is running. When you stop, switch to one on odd days and two on even days. When it is time to start the motor, you may have to switch to the other battery to start the motor. Then switch to both for the ride home.

Of course, I leave my switch on both all the time. I do not have any heavy electronics, and could get away with one battery.
 

Tabes117

Petty Officer 2nd Class
Joined
Mar 8, 2008
Messages
181
Re: Dual Battery Switch Set Up Question

I run 4 speakers off the head unit and 4 speakers off my 4 channel amp. I run it for hours off 1 of my 2 batteries without problem. My amp at first would cut out from heat, till I added a fan.

Dont know maybe your amp is drawing to much power. Maybe run it off a relay. I added a light bar to my tower. It was drawing to many amps and would blow the circuit breaker after a few minutes. I added a relay and it solved my problem.
 

bowman316

Lieutenant Commander
Joined
Oct 21, 2008
Messages
1,822
Re: Dual Battery Switch Set Up Question

The textbook answer is to Start on one (or whatever your desiginated starting battery is), and keep it on that battery when running. Then when not running, and using accessories, switch to 2, make sure your are not using your starting battery.
Both is only intended for emergencies only, when both batteries are near dead.

The engine can not charge both batteries efficently when you are driving. Just worry about charging the one.

And charge the other with a battery charger at home.
Otherwise you run the risk of getting stranded with no battery.
 

Starcraftguy1

Petty Officer 1st Class
Joined
Sep 6, 2008
Messages
327
Re: Dual Battery Switch Set Up Question

I think it depends on how far you plan to go on the initial run the motor part.My buddy has the all or 1 switch.I usually drive his boat with the gas motor,he is a trolling motor type of guy.I always keep his batteries charged so that I can get home,he has a 18' CrestLiner,with a 24 volt trolling motor setup,they go dead usually,because he won't buy new batteries,but the starting batteries are always charged up.If we are sitting in one place for a long time,I will switch to 1 battery on the switch,just for the fish finder and lights if dark.Then after we get running turn to all to charge both.
 

kyle f

Chief Petty Officer
Joined
Sep 5, 2007
Messages
408
Re: Dual Battery Switch Set Up Question

OK, so I can charge both at the same time off the motor, but it is better to charge just one.

THough, it sounds like the stereo is killing the dang batteries faster than it should. Any further thoughts on that? I could feel no real hot spots on the Amp chassis. I know that doesn't gurantee no localized heat up... but since there is still a warranty, I don't want to go breaking stuff open just yet.
 

swordfish25

Petty Officer 2nd Class
Joined
Mar 18, 2009
Messages
117
Re: Dual Battery Switch Set Up Question

If the motor is running and it still quits, you probably have a problem with the amp. With the motor running (charging) that rules out the voltage. I had an amp that would shut down if I tried to over power it (too much volume).
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Dual Battery Switch Set Up Question

There is no "recommended, right, or wrong" way to use a dual battery switch. What is important is that you understand what the switch is actually doing. Understand that OFF removes power from everything that is fed from the COM terminal on the switch. In the BAT 1 position (whichever battery you have connected to the #1 post on the switch) powers everything connected to the COM terminal. Likewise, when running, ONLY BAT 1 will charge. This is the same scenario for BAT 2. If you have a high power stereo system powered from BAT 2, then I suggest you replace that battery with a deep cycle battery rather than a normal starting battery. A dual purpose (starting/deep cycle would also work but a true deep cycle is best in that application). The BOTH position does not have to be used for ANY purpose but it can be used to charge both batteries when under way. If you have an I/O or a bigger outboard with a high output alternator, it will indeed keep two batteries topped off provided either or both of them were not deeply discharged. And remember also that a 10 minute run back to the dock will not fully charge any deeply discharged battery whether it's your starting battery or the house battery. My technique is to use the start battery to start the engine (switch to BAT 1). After the engine starts, switch to BOTH and be on your way. When you stop somewhere to swim, listen to tunes or fish, switch to the house battery (BAT 2). This prevents drawing down the starting battery. If for some reason you run that battery down you can still switch back to BAT 2 or BOTH. In that event, when you do get the engine started, since you ran down BAT 1, set the switch to BAT 1 to get that as fully charged as you can in the next run. A battery switch is versatile so you can use it in whatever manner you need. The key is understanding what you want to achieve.
 

kyle f

Chief Petty Officer
Joined
Sep 5, 2007
Messages
408
Re: Dual Battery Switch Set Up Question

Sad to say, but that would tick me off if that is the case. I mean seriously, I have had cars to pump out alot more volume than I am asking of this system, and they never shut down. :mad:

I am cleaning the terminals of the batteries tonight, and putting them on a trickle charge to make sure they get a good charge.

Will try it again tonight and tomorrow evening and see what happens.
 

kyle f

Chief Petty Officer
Joined
Sep 5, 2007
Messages
408
Re: Dual Battery Switch Set Up Question

Well, I took the boat out last night. The previous night I gave both batteries a charge with my 10A charger whiel at home. Ran it this time on "ALL" setting. Had no problems.

I guess its time to sit down and start lookign at how thigns thing is wired.

How do I tell which battery is which. Would turnign on the lights, blower, bilge pump, heaters, and Nav Lights then taking a voltage reading accross the post work? As in, take a reading while in position "1" off each battery, then turn it all on, take a reading on both batteries and the one with a Voltage drop would be battery 1?

Thanks
 

PondTunes

Petty Officer 1st Class
Joined
Jun 7, 2007
Messages
387
Re: Dual Battery Switch Set Up Question

the amp cut out most of its volume after about 5 minutes.

( You can still crank it and you can hear it, but it sounds like its at 2 on the volume control, but its at 32), I flipped the switch from "2" to "1" and it came back on for a while. Shut off again and all the interior lights dimmed... switched to all.... repeat.


The above two statements puzzle me.. Normally an amplifier will put out a little more juice with the engine running because it's getting 14+ volts from the charging system this could make things a little louder, shutting the engine off shouldn't produce a huge drop in volume. Nor should running the battery dead, as the radio/amp should cut out at about 10.5 - 11 volts so that it doesn't burn up due to low voltage. That being said; if your volume is at 32 with the engine running and sounding fine then when you shut the engine down it drops to sounding like its at 2 then there's a problem somewhere, the only thing that has changed is the presence of charging voltage, the radio/amp don't care what the engine is doing as long as it's charging the battery..

Could there be a speed sense wire hooked up to this radio that is supposed to adjust volume based on speed? Could there be a wire hooked up to the radio that is a telephone mute? Lots of radios have extra wires there for illumination, cell phone mute, and VSS.. If one of these wires were hooked up to the ignition circuit perhaps switching the engine off is the equiv of hitting the ATT or mute button.

1) Check your radio wiring, ATT/Cell Phone Mute could be light blue or brown.
2) If a speed sense or ATT wire is hooked up cut it loose not really needed.

That's really the only thing I can think of that could possibly cause the volume output to reduce to the extreme you said. If it was a little louder or softer with the engine off that could be explained by the extra voltage.
 

PondTunes

Petty Officer 1st Class
Joined
Jun 7, 2007
Messages
387
Re: Dual Battery Switch Set Up Question

Well, I took the boat out last night. The previous night I gave both batteries a charge with my 10A charger whiel at home. Ran it this time on "ALL" setting. Had no problems.

I guess its time to sit down and start lookign at how thigns thing is wired.

How do I tell which battery is which. Would turnign on the lights, blower, bilge pump, heaters, and Nav Lights then taking a voltage reading accross the post work? As in, take a reading while in position "1" off each battery, then turn it all on, take a reading on both batteries and the one with a Voltage drop would be battery 1?

Thanks
With the engine OFF.
1) Set the switch to position #1
2) turn on the nav lights or something that you can see.
3) unhook one of the batteries, if lights go out that's battery #1
4) reconnect.
 

sportsmanphil

Petty Officer 1st Class
Joined
Mar 8, 2009
Messages
257
Re: Dual Battery Switch Set Up Question

May I suggest you load test you batteries? With electrical problems, you need to start at the source, the batteries. It is posible to have a single bad cell in a battery which could allow it to work but be short lived or weak.

Load testers are not expensive, with a boat I suggest you own one.

Basically its a box with two clamp on leads. In the box is a large coil wired to a switch. You clamp it on the battery and see the voltage. Hit the load switch for no more than 10 seconds and it turns on the coil, eating up electricity forcing the battery to work. You watch the voltage drop on the meter. Most load testers will show you if the battery is bad/weak/good. These testers also allow you to watch the recovery time.

I suggest you spend a little extra and get one with an amp meter also. They can come in handy to test amp loads by placing them between the + terminal and the + cable.


Back to your problem, it soulds as if your amp is cutting off due to low voltage from the battery.
 

krakatoa

Senior Chief Petty Officer
Joined
Aug 8, 2008
Messages
705
Re: Dual Battery Switch Set Up Question

The textbook answer is to Start on one (or whatever your desiginated starting battery is), and keep it on that battery when running. Then when not running, and using accessories, switch to 2, make sure your are not using your starting battery.
Both is only intended for emergencies only, when both batteries are near dead.

The engine can not charge both batteries efficently when you are driving. Just worry about charging the one.

And charge the other with a battery charger at home.
Otherwise you run the risk of getting stranded with no battery.

Here is your best answer.... This is what I do when launch.
 

kyle f

Chief Petty Officer
Joined
Sep 5, 2007
Messages
408
Re: Dual Battery Switch Set Up Question

The above two statements puzzle me.. Normally an amplifier will put out a little more juice with the engine running because it's getting 14+ volts from the charging system this could make things a little louder, shutting the engine off shouldn't produce a huge drop in volume. Nor should running the battery dead, as the radio/amp should cut out at about 10.5 - 11 volts so that it doesn't burn up due to low voltage. That being said; if your volume is at 32 with the engine running and sounding fine then when you shut the engine down it drops to sounding like its at 2 then there's a problem somewhere, the only thing that has changed is the presence of charging voltage, the radio/amp don't care what the engine is doing as long as it's charging the battery..

Could there be a speed sense wire hooked up to this radio that is supposed to adjust volume based on speed? Could there be a wire hooked up to the radio that is a telephone mute? Lots of radios have extra wires there for illumination, cell phone mute, and VSS.. If one of these wires were hooked up to the ignition circuit perhaps switching the engine off is the equiv of hitting the ATT or mute button.

1) Check your radio wiring, ATT/Cell Phone Mute could be light blue or brown.
2) If a speed sense or ATT wire is hooked up cut it loose not really needed.

That's really the only thing I can think of that could possibly cause the volume output to reduce to the extreme you said. If it was a little louder or softer with the engine off that could be explained by the extra voltage.

The boat moving or stopped has no effect on the situation. Pressing the mut button will mute all sound at any time. I know of these systems, but as far as I am aware, this boat has neither.

I think it is simply a weak battery, and I am going to remove them and have them tested before the next trip put. This past on, while running on "ALL" everythign went fine. Seems to show that one or both are weak.
 
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