Crazy battery switch problems

[crowmobe720]

I have a 2003 SAN 210. I was having some battery issues last fall, it seemed like the boat was not starting well, I don't recall the specifics. I got two new batteries and nothing really changed. Then I realized that the battery switchs were broken. There was an on/off for each battery, and the plastic was broken inside. I thought that was the issue and replaced them with a Perko 8501 battery switch. I have used those in the past, and had better luck with them. Things still never worked quite right for the rest of the year.

When the switch is set to:

* Battery #1 - The boat rarely starts, and it sounds like the battery is almost dead. The engine turns over and then just quits. The odd thing is that the power gets shut off to the dash start controls. I have to put the code in again in order to press start again. Even odder, one time it did actually start the boat after a struggle, but even with the engine going the start controls lost power. I had to put the code in again in order to press "stop" and shut off the engine.

* Battery #2 - The boat is more likely to start, but sounds even worse. If I give the engine any gas then I hear squealing from what sounds like the alternator. If I give more gas then the engine shuts down. It is like something is trying to spin the belt the opposite direction.

* Both - It acts like Battery #2

* None - nothing happens, as expected


Here is how everything is wired:
Each battery negative runs to different bolts on the engine block. The positive on the batteries runs to either #1 or #2 on the Perko switch. The Comm on the Perko switch is connected to the starter and all the other electrical on the boat (dashboard ACC, shower pump, amp).

Some experiments:

I removed everything from the Comm except what was necessary (just starter and dash acc). No change.

After reading about this I saw where some people run the neg from one batter to the other battery's neg. Then they run that one to the engine bolt. I tried this and everything acts the same.

I switched #1 and #2 on the Perko switch. The behavior stayed the same, but the numbers switched. The symtpoms seems tied to the batteries, rather than the positions on the switch.

I took the Perko switch out entirely. I ran what was originally battery #1 straight inline (+ to the starter and - to engine bolt). Everything works perfectly like this.

I then put the Perko switch in line without adding the second battery. I just put the Perko switch between the battery + and the starter. I once again get the behavior described above for battery #1.

Could it be the Perko switch? It is almost new and some of the issues predate the switch. But when I take the switch out the issues are gone. IS there any way to test the switch? I'm thinking it is more likely that I have something misconfigured, but I don't see what it could be.

[crowmobe720]

Here are a few pics. You can see the configuration of the batteries one ground come from the engine bolt on the right side of the pic. Then it is connected to the negative terminal on the other battery on the left of the pic. both positives go to the Perko switch on the left, then from the Perko to the starter. Another pic shows the connection at the starter. What could be wrong? What would explain the symptoms?

[ArmourNautique]

Sounds like some strange problems. I would definitely check your kill switch and your master toggle switch if you have not already. I had some similar sounding issues and the toggle was the issue. Replaced it, and like magic, All my issues went away.


Sent from my iPhone using PLT Nautique

[charlesml3]

If you take the switch out of the equation and everything works fine, then it HAS to be the switch. Sounds to me like it's a dud.

-Charles

[DW SD]

Change the switch.


Sent from my iPhone using PLT Nautique

[MLA]

You need to break out the digital volt/ohm meter and do a voltage drop test on the main ground and main positive cables.

[crowmobe720]

I don't think it is the switch (or at least not just the switch). I asked Perko and they explained that I should put the hot from the battery to the Perko comm, and then the other wire from the comm to the starter. So the Perko switch is just letting me clamp the two wires together on a single bolt. In that setup, it acts weirdly as explained above. Maybe it is the cable, but it tests fine for ohms. From what I have read it isn't ideal to use two 5 ft sections of 2 awg write (10" combined). But that worked fine in the past.
Even when the battery was hooked directly, it had some trouble starting. So I changed out the starter naively hoping that might fix everything. It didn't. And then it stopped turning over at all. Sometimes if I press start I get a click, most of the time nothing. Thinking that I may have bought a dud starter, I put the old one back in that was still working. I still get nothing. Things are just getting worse, I at least had a running boat until this.

[MLA]

I asked Perko and they explained that I should put the hot from the battery to the Perko comm,

Nope, nope, nope!

[crowmobe720]

"Nope, nope, nope!"
Yes. I was explaining how to diagnose whether it was the switch or not (not the way that it should be connected for use). Did you read my post out of context?

[MLA]

An ohm reading on that large of a cable is not going to tell you anything.

[crowmobe720]

So how would I tell if the cable was causing problems?

[MLA]

post # 6, voltage drop test

[crowmobe720]

Okay, now I understand how and why to perform a voltage drop test thanks to this video.
https://www.youtube.com/watch?v=paw80mS_Kxg

I don't think this helps me today though because I can't even get the engine to turn over at all (or even click). But I have seen other videos that don't require the engine to be starting to get a read on the voltage drop. Is this a requirement?


I've rephrased my problems in terms of the boat not starting (since the Perko switch is not suspect and not actually part of the system at the moment).
https://www.planetnautique.com/vb5/f...10-won-t-start

[crowmobe720]

Okay, I hooked up the battery directly to the starter. Then I hooked the voltometer up to the pos battery terminal, and the other end at the cable where it attaches to the starter. When I start the engine (which doesn't make a sound but apparently closes the circuit) I get the full 12.4 volts that the batter had. Does that mean the cable is bad?

[MLA]

You DONT need to try and start the engine, or in a case, turn on a load. Voltage is the difference in potential. You have 100% potential on the B+ side and 0% on the B- side. Thats how we rear 12V across the battery terminals. When touching the leads to both ends of a cable or circuit, you should have zero potential, in other words, 0 voltage. if you measure voltage, there is "potential" or resistance in the cable. This prevents current flow, which equals poor work produced on the other end. In your case, a starter not working.