What does this switch do and how is it likely wired?

Have a fish and ski boat that is new to me and the prior owner didn't know the answer to this question. There is a switch panel on the bow that I'm trying to figure out and wondering how its probably wired. The boat has 2 x 12V batteries in the stern compartment that have a Perko master switch on it. When this is on, both batteries work. When its off, all power is off. I usually keep this off when at home and I have my in-boat charger wired straight to the batteries.


Now to the panel on the bow. The first switch is 3 position... I have been leaving it in the middle. It has a "Charge 2-12V" setting, and a "Run 12/24V" setting. I am pretty sure that with it in the center "unmarked" setting, the boat charges both batteries because after I have been out all day and return and hook up the onboard charger, the batteries are not in need of charging. So I have no clue what those other settings do, or how they are wired to the batteries. I also don't know if the master switch was there from the factory, so possibly some overlapping duties here??? If no help is available here, I'll eventually spend a raining afternoon trying to trace the wires. But from the bow to the stern will take some effort. So any ideas?

The last switch seems to control what the gauge on the right shows for voltage. If the left switch is in the center where I leave it, then the gauge will show a voltage reading when put in "Battery 2" position, but shows nothing on the gauge when in "Battery 1" position. It does the same if the left switch is down. If the left switch is up, however in "Charge 2-12", then moving the right switch to "Battery 1" or "Battery 2" will result in a reading on the gauge. This also seems to work regardless of whether the red master switch is turned off or on, so these front panel battery switches are bypassing that master switch.

It bugs me to not understand what the switches do and how they are supposed to be used. I have an electronics degree, so if I could find a wiring diagram then that would be helpful, but Glasstream has been defunct for years and no clue where to find a diagram. My assumption is that this is probably a common wiring setup that exists on other boats so maybe someone here could help me figure it out before I start trying to climb into to tiny spots to explore (and possibly break something that isn't already broken).

Re: What does this switch do and how is it likely wired?

Looks to me like the Perko was a add-on. Break out the meter and chase the wires, you'll be glad you did.

Re: What does this switch do and how is it likely wired?

Lets start with the Battery 1-2 switch (the one on the right). You are correct in that the gauge reads the voltage available at trolling motor BAT 1 or BAT 2 depending on which setting the swtich is in. HOWEVER -- You need to understand that your boat is configured for use with trolling motors that have the capability of operation on EITHER 12 volts or 24 volts. If the meter is not reading voltage from one battery, that wire is disconnected. That switch has the meter connected to the center terminal and one wire from the POS terminal of each battery going to each of the other two terminals on the switch. Those two wires may actually come from the switch on the left. Meter ground goes to the ground side of the troller motor battery system.

24 volts obviously requires two batteries wired in "series" and the switch on the motor must be set to 24 volts. For 12 volt operation the switch on the motor would be set to 12 volts. For battery charging purposes using the trolling motor receptacle at the bow of the boat you would set the left switch to 2-12 charge. This places the batteries in "parallel" so they can be charged simultaneously using a single output 12 volt charger.

You mentioned an ON-BOARD charger. An on-board charger is a single or multiple output battery charger that is permanently mounted in the boat and plugs into shore power (120 VAC) at the dock. Those charger outputs are connected directly to the batteries and the setting of the switch on the left would have no bearing on its use.

The ON-OFF switch appears to be installed as a master starting battery disconnect switch. Can't tell for sure though as all you show is the switch. Have no idea what the smaller wires are for on that switch. Your boat may have a bilge pump with an automatic switch so perhaps these wires are associated with the pump.

Re: What does this switch do and how is it likely wired?

I think you just boosted my knowledge on this about 500% Silvertip.

So Battery 1 and 2 on that switch has nothing at all to do with my cranking battery? I only have 2 batteries... one for crank and one for trolling, so I assumed incorrectly that was the two batteries it was talking about (and the prior owner told me that too I think). Adding to the mystery is that I don't see anywhere in the boat that a second trolling battery could be placed unless some significant change was made.

I just confirmed that the master switch has nothing to do with the trolling motor.. my error on that. So two completely separate systems.

The onboard charger I added when I got the boat, so its just simply wired to my two batteries directly... on trolling and one crank.

Back to the trolling system. My trolling battery has two similarly looking red wires and two black wires attached to the positive and negative poles (not including the charger wires I added). I'm wondering if there are two so that I could put in a second battery and split them? Not sure if that makes sense with the way the other stuff is working. If that was true, the the gauge should always read something in position 1 or 2 I guess.

The trolling motor socket there has 3 wires and only 2 are being used by my trolling motor. Do 24V trolling motors use 3 wires?

Now that I have a better understanding of how its supposed to work... makes sense after you explained it... I will pull that panel off and look at how its all wired up and see if I can figure out where the 2 wires on each pole of the battery split off to. In the mean time I'll just leave the left switch in the center unmarked position which seems to be working.

Thanks so much for your insight. And Royal0014, I will get the meter out and do some checking. That is what raining afternoons are good for!

Re: What does this switch do and how is it likely wired?

Oh man!!!!!! I'm glad your confidence is boosted because mine isn't after what you just described. The devil is in the details as usual. When you show pictures of a panel that is clearly set up for a 24 system one can reasonably assume you actually have a 24 volt trolling motor (or a dual voltage 12/24) especially since you talked about two batteries. As I pointed out, for 24 volt operation you obviously need two 12 volt batteries in series. One should NEVER use the starting battery as one of those two batteries. So now we need to start this all over. This time "I" ask the questions.

Be very clear when you answer these questions.

1) Do you have a trolling motor?
2) If yes, is it a 12 volt, 24 volt, or combination 12/24 volt version (voltage selector switch on foot pedal).
3) How many batteries "total" do you have and what are they used for? (Example: one starting battery, one trolling motor battery. Or one starting battery and two trolling motor batteries. Or one starting battery and one house battery).
4) How are the batteries wired -- cover each battery separately. Trolling battery has xx wires (one red one black, two red, two black for example).
5) How many wires are there in the cable leading into the trolling motor (if you have one). The answer will be two or three.
6) Where do the large wires go that are attached to the large ON-OFF switch?
7) Where do the small wires go that are attached to the large ON-OFF switch?

What we do know is that your boat is set up for a 12 volt, 24 volt, or combo 12/24 volt troller. What we don't know is what you have for a troller motor or if you even have one.

It now "appears" that only one battery is wired to the panel and on to the trolling motor receptacle so that system can provide ONLY 12 volts regardless what type of trolling motor you have.

If you only have one battery in the troller system, that would account for why the voltmeter only registers on one switch setting. (Because the other battery isn't there!)

If this sound like I'm ragging on you be assured I am not. There are as many wiring configurations for these 12/24 setups as there are people who designed them and other people who got creative by modifying the system. As is apparently the case with your boat, some creative wiring has been done which complicates answers to questions on these systems. I have some diagrams for several of these systems but I will not post them until I know which one most closely represents your system and what mods have been done.

Re: What does this switch do and how is it likely wired?

From your description, it used to have 2 batteries dedicated to trolling, or a 12/24 volt trolling motor using the main battery and a second battery, (not a good idea if you don't like to paddle)

Anyway, the switch is a crossover switch that switches the batteries from parallel (12v) to series(24v) There are 2 pairs of wires going to the switch, 12 v from each battery, and 1 pair going to the trolling motor.

If that is true, and it was unmodified, and someone parallelled the wires at the battery with no fuse, and the switch was thrown to the 24 volt position, the switch guts are now a thin plating on the inside of the housing.

I would bet that it's just disconnected and hot wired parallel.

hope it helps
John