Weird solenoid behavior

[mattsmall1972]

On my previous boat, I removed the Perko 2-battery switch and replaced it with a battery isolator so that both batteries would charge while running. I then wired the starter to one battery, and left the other battery as the house battery. The house battery has a run to a solenoid which is turned on by a master rocker switch on my panel. All of the electronics are run from the house battery via the solenoid. This is a really nice setup as it prevents the need to turn the big Perko switch on/off (it was in a weird place) and prevents the electronics from slowly draining the house battery when not in use.

I have a new boat, and wanted to do the same thing. I bought the exact same battery isolator and solenoid. Up under the console is a stereo amplifier with a large battery cable that runs straight to the battery. I cut this cable and left it running to the battery, along with enough cable for the amp as well. I hooked up both sides of the cut wire to the main lugs on the solenoid , as well as a smaller extra cable on both sides. The smaller cable on the battery side is meant to go to the master rocker switch. The master rocker switch will then turn the solenoid on/off. The smaller cable on the other lug will go to the accessories panel.

I got into the console last night and wired everything up. The solenoid does not come with any instructions, and I figured that when powered, the solenoid's main lugs become a continuous path. When I powered up the solenoid, the voltage I was reading at point #1 was positive voltage, but negative at point #2. I am really confused about what's going on.

Just to be clear, this is the solenoid I purchased: http://www.amazon.com/gp/product/B0064MX7US?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

This is a schematic I just did to show you the hookup:

Now, I am not quite sure what else is going on, but my voltage measurements were weird. I was only seeing about 8 volts at point 1, while I was sometimes seeing -8 at 2, sometimes -12. I tried activating the solenoid switch both ways but it was the same. What was interesting was that I never heard a distinct click as if it was on, but I could clearly see the voltage change from 0 to -12 using the multimeter.

Could this amplifier cable be my problem? I haven't tried changing the direction of the voltage flow across the solenoid yet, and I am going to do that, but I wanted to throw this out there to see if there's something I'm missing. This is a basic electrical switch, it shouldn't be that hard.

 

[gm280]

matt, the first issue is that YOU assumed the new solenoid is wires like a typical starter solenoid. And that may not be the case. I have see so many versions of starter solenoids that look identical but wired internally different. So first thing to do is ohm out the solenoid all by itself out of the circuit. While it may seem obvious as to where wires should go, some solenoids don't get wired that way to operate. The two small terminals may not go to the coil inside to energize it. And the two larger terminals probably will pass the heavy current once you have the solenoid figured out. Some times one of the smaller terminals goes to the coil but the other coil connection goes to the ground metal of the mounting bracket. So check out what you bought first. It really sounds like it isn't a typical starter solenoid from your comment. JMHO!

 

[mattsmall1972]

Hi GM - you bring up some good points. The thing is that I have this exact same solenoid running just like this in my other boat. However, I will take it out of the circuit and test it all around. Thanks for the response.

 

[mattsmall1972]

After reading this I went back and read the reviews on Amazon. Someone found the schematic on the manufacturer website. Here it is:

Seem pretty simple.

 

[gm280]

After reading this I went back and read the reviews on Amazon. Someone found the schematic on the manufacturer website. Here it is:

Seem pretty simple.

Yes matt, I seen that as well. But I also seen so many negative responses saying they ordered two or three and none of them worked. Which leads me even more to the fact that it may not be the typical wiring schematic of a standard starter solenoid. So do check it out. There can't be that many folks unable to get theirs working right if it is a standard setup. The manufacturer would go out of business if they allowed that many defective products out. I'd be really interested to see what you find out from ohming it out. JMHO!

 

[sam am I]

Matt,


Look closer at your schematic from post # 1 and post # 4, if you wired according to # 1, see anything odd when you compare it to how the actual solenoid's is pinned out as indicated in post # 4?

Pin #2 goes where?

If then your schematic in post # 1 is simply just not labeled right but, and you are in fact wired up proper accordingly using post # 4, then it sounds like you have a ground issue. Re-assure the pin that doesn't go to the master switch (#2 or #3) of the solenoid has a proper ground. The solenoid shown in post #4 will click once proper power and ground (pins #2 and #3) are present regardless of the input/loads (pins #1 and #4)

 

[mattsmall1972]

Hi Sam - the numbers in the schematic in post #1 were my own numbering system. The ones in the manufacturing diagram are different than mine. That said, I'm not quite sure what you are asking.

 

[mattsmall1972]

Thanks for the explanation. I will double-check the ground today.

 

[sam am I]

If figured just a possible labeling case as well..........No worries, then as stated, just check that the solenoid's pin's #2 and #3 are properly wired. For example and from the manufacturers wiring diagram in post #4, if pin #2 goes the the master switch, turn on the master switch, and use your voltmeter to check it. e.g. with the meter's black lead on the battery's ground post and the meter's red lead to pin #3, pin # 3 better be zero volts. If not, you just have a bad ground on the solenoid.

And of course, pin # 2 better be 12 volts.

 

[mattsmall1972]

Sam, you were right - my ground wasn't attached as I thought it was. It all goes back to basics. It's just so weird that current finds a way back through the circuit even when you don't think it can.

I had unattached the solenoid and connected it directly to a battery to get the good click sound and measured the resistance. I got a nice beep on the multimeter when I did this. When I went back to the boat, I checked the voltage at the battery on the amp cable and it was good. Then I saw the black ground cable sitting there with no connector on it. Put on a new connector and ran to ground - all is happy now.

Thanks all.

 

[sam am I]

Cool , glad ya got it.

Just a small favor? Go easy on the amp when it's a nice quite calm evening on the water, us old guys value the peace and quite more than loud amps.

 

[mattsmall1972]

Oh... the stereo was already installed on the boat when I bought it. I don't prefer it that loud.