Okay, I'm Officially Stumped.

[Red_Dog]

I finished the charging system wiring Monday - came up one ring terminal short. Tuesday, went back and completed everything. Minor glitch with the connection to the battery charger; a just enough lose connection at the charger. Connected the boat to shore power, turned the AC main on, no smoke or flames, checked the cabin outlets - good. This time the charger came right on line.

So, I happily flipped the DC main and started going through the circuits. Everything came on as it should. No problems. Turned everything back off and just let the batteries charge up.

Feeling pretty pleased with myself, I thought it time to take a break and enjoy a beverage. While relaxing, it dawn on me that I had power to the DC side, but I didn't remember turning a battery on. Checking the switch, sure enough it was off. So much for a relaxing break.

When I did the wiring, I wired the positives of each bank one at a time, just so I didn't confuse myself. Going back and checking the connections - one bank at a time - if tab A was suppose to go into slot B, that's what I found.

I'm stumped.

I do have two suspects in my mind:
- The schematic I have for the 2GM20 shows this vague, nebulaes connection from the the back of the alternation that kind of, sort of shows it connecting to the battery switch. Not physically finding this wire, I connected directly from the alternator to bank 1. If there is an existing connection, by connecting to bank 1, did I bypass the switch?
- The battery switch itself. It's 35 yrs old. With all of the detaching and re-attaching of wires and just went tango uniform on me?

However, I could be completely wrong. Attached is a PDF of the system as built.

 

[Jim26m]

Your blue sea voltmeter is wired hot from both banks. Is that 2 separate terminals, or are the battery banks tied together on one terminal at the volt meter? Is that where you noticed you have D.C.? Or, do you have the entire D.C. system hot?

 

[Red_Dog]

The voltmeter is wired to a 3 position switch to check each bank individually. But yes, investigating things, whether on bank 1 or bank 2, I showed voltage.

 

[Jim26m]

The voltmeter is wired to a 3 position switch to check each bank individually. But yes, investigating things, whether on bank 1 or bank 2, I showed voltage.

Sorry. Are you saying that if you flip the monitor switch to bank 1 or bank 2 it shows voltage? Seems like it would the way you wired it.

When you have the main bank selector switch off, are you getting D.C. everywhere, radio, lights, etc? If it's only showing voltage at the monitor, you can go back to your beverage.

 

[dlochner]

While relaxing, it dawn on me that I had power to the DC side, but I didn't remember turning a battery on.

Did you notice the DC power was on by looking at the voltmeter or by turning things on?

The voltmeter is reading the voltage before the 1-2-B-Off switch. So long as the VM switch is on, it will read voltage.

 

[Brian D]

I would go back to the battery switch, disconnect both banks and see if you still have anything on. There should be nothing. Reconnect one bank, turn something on (a light?) and move the switch between 1-both-2-off. You now the rest of the drill.

 

[Jim26m]

I would go back to the battery switch, disconnect both banks and see if you still have anything on. There should be nothing. Reconnect one bank, turn something on (a light?) and move the switch between 1-both-2-off. You now the rest of the drill.

As @dlochner points out, he wired the battery voltage monitor off the hot bus on both banks BEFORE the battery switch. If you disconnect the switch, it will still show bank voltages at the monitor. He hasn't said whether he actually has D.C. distribution as far as I can tell. Appears to be just reading voltage at the monitors, which is exactly the way it's wired...

 

[Red_Dog]

Sorry. Are you saying that if you flip the monitor switch to bank 1 or bank 2 it shows voltage? Seems like it would the way you wired it.

When you have the main bank selector switch off, are you getting D.C. everywhere, radio, lights, etc? If it's only showing voltage at the monitor, you can go back to your beverage.

The voltmeter is a 1-2-3 switch for three battery banks, no off position. I'm using only the 1 and 2 positions. I had DC power for all devices I turned on with the battery selector switch off. Upon realizing the selector switch was off and leaving it off, I checked the voltmeter's 1 and 2 position and both showed voltage.

Did you notice the DC power was on by looking at the voltmeter or by turning things on?

The voltmeter is reading the voltage before the 1-2-B-Off switch. So long as the VM switch is on, it will read voltage.

As I mentioned it was by turning things on. As for the wiring of the voltmeter switch, I did it per Blue Seas panel wiring diagram. (Writing this, It occurred to me to make contact with them to make sure I interpreted the drawing correctly.)

Brian, I will make sure to complete the drill next time at the boat.

 

[Jim26m]

The voltmeter is a 1-2-3 switch for three battery banks, no off position. I'm using only the 1 and 2 positions. I had DC power for all devices I turned on with the battery selector switch off. Upon realizing the selector switch was off and leaving it off, I checked the voltmeter's 1 and 2 position and both showed voltage.



As I mentioned it was by turning things on. As for the wiring of the voltmeter switch, I did it per Blue Seas panel wiring diagram. (Writing this, It occurred to me to make contact with them to make sure I interpreted the drawing correctly.)

Brian, I will make sure to complete the drill next time at the boat.

The instructions for the 8084 show the meter wiring as you did it. Makes sense that you would want to check battery levels without energizing everything.

Now that I understand that you have D.C. power everywhere with the battery switch off, I'm suspicious of your wiring at the main selector switch (which is apparently where @Brian D was going).

Since your starter is wired to the common pole on the battery selector, check to make sure there are no other wires on the main starter lug that might be back-feeding. Unless the switch is faulty, or you wired it wrong, my money is on the starter connection.

 

[heritage]

I remember when redoing the electrical circuits on my H27 with a 2gm20f, that there was a wire connecting the output of the alternator to the starter solenoid lug which tied in with the main starter cable to the common lug of the selector switch. I replaced it with two wires, one from the alternator to the batteries and the other from the starter to the common lug of the selector switch. The original setup required only one wire to the battery switch, but it did present the possible problem of a fried alternator if the selector switch was selected to "off" with engine running.

If that cable from the alternator to the starter is still on your engine, it bridges your batteries directly to the main dc distribution panel regardless of the battery selector switch position.

 

[Red_Dog]

Checked. Two wires attached to the common are the starter lead and the panel lead. From the common, I go to the starter, nothing else is attached to the starter.

The nebulaes wire -the one I couldn't find - that I spoke in my OP. I pulled up the schematic. Looking closer, that wire is shown from the alternator attached to the starter. Could the direct connection from the alternator be doing the same back-feeding?

 

[Red_Dog]

I remember when redoing the electrical circuits on my H27 with a 2gm20f, that there was a wire connecting the output of the alternator to the starter solenoid lug which tied in with the main starter cable to the common lug of the selector switch. I replaced it with two wires, one from the alternator to the batteries and the other from the starter to the common lug of the selector switch. The original setup required only one wire to the battery switch, but it did present the possible problem of a fried alternator if the selector switch was selected to "off" with engine running.

If that cable from the alternator to the starter is still on your engine, it bridges your batteries directly to the main dc distribution panel regardless of the battery selector switch position.

I'll have to do a better job of finding that wire next time around. If I still have DC power after disconnecting the bank 1 and 2 leads at the selector switch, and still can't find the wire from the alternator to starter; I may try disconnecting my direct alternator-bank 1 lead.

 

[Red_Dog]

Just received an answer from Blue Seas (That was quick.). Here's what they have to say about wiring the voltmeter monitor switch:

"This is one of those there is no right or wrong way of wiring a voltmeter. In more opinion and what you want is what important. A meter wired directly to the battery will give a true voltage at the battery. Some will want the true voltage at the panel. Both are correct."

 

[Jim26m]

Checked. Two wires attached to the common are the starter lead and the panel lead. From the common, I go to the starter, nothing else is attached to the starter.

The nebulaes wire -the one I couldn't find - that I spoke in my OP. I pulled up the schematic. Looking closer, that wire is shown from the alternator attached to the starter. Could the direct connection from the alternator be doing the same back-feeding?

What other wires are on the alternator? The one you have going from the charging lug to the bus shouldn't be a problem.

 

[Maine Sail]

When you fed the alternator directly to the house bank, did you open the loom and remove the jumper between Alt B+ and the starter post?

Remember, when the alt is direct wired to the house bank the B+ on the alt is always hot. If the jumper between the Alt B+ and starter motor was not removed, the engine is now live not just the Alt B+ terminal. We've seen this one a number of times.

 

[Red_Dog]

When you fed the alternator directly to the house bank, did you open the loom and remove the jumper between Alt B+ and the starter post?

Remember, when the alt is direct wired to the house bank the B+ on the alt is always hot. If the jumper between the Alt B+ and starter motor was not removed, the engine is now live not just the Alt B+ terminal. We've seen this one a number of times.

I believe this is where Heritage was going with his response.

When I first went to wire the alternator-bank 1, I knew this jumper was suppose to be there. I opened the loom (untapped as the case was) and could not find it. According to the schematic, it was to be connected before a 30 amp inline fuse. found the fuse, but not the connection or the wire. I shrugged my shoulders and connected the alternator to bank 1 connection.

My thought of disconnecting the direct feed at the alternator is that if things work correctly, then the jumper is present. Go find it.

 

[Maine Sail]

Should be a red wire from alternator B+ to the starters battery connection post. Depending upon the harness it is typically between 7" and 16" long.. It's usually 10 GA ...

 

[Red_Dog]

Should be a red wire from alternator B+ to the starters battery connection post. Depending upon the harness it is typically between 7" and 16" long.. It's usually 10 GA ...

Thanks, that gives me a better idea of what to look for. As a side note, when connecting the alternator to bank 1, there is at least two other wires connected to the alternator positive. Going from the alternator end, might be a better starting place.

 

[Benny17441]

Eliminate the possibility that only one of the banks may be hot while the Battery Switch is Off. Disconnect one at a time and test. Eliminating one bank if possible may simplify your search. Comparing what may differ from one bank circuit to the other may direct you to the answer. If both are still hot then look for where one connects to the other. The Switch is likely being bypassed.

 

[Red_Dog]

I came. I saw. I problem solved.

It was the red wire on the back of the alternator. It was easier than trying to find at the back of the starter. All of five minutes to take care. Oh - that was the only wire connected to the back of the alternator.

Beer and sandwich are happily chillin' away while I do some other things.

Thank you all!