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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Fri Apr 23, 2021 2:22 pm Post subject: Electric Question / Scrambled Eggs |
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I have a mystery wire that I installed myself. Here's what happened, I think.
A while back I installed a Pertronix ignition. I think I have added a wire that I may not need or want in the system.
Instructions show TO IGNITION from the positive side of the coil. Now here is the scrambled eggs part. (see photo below)
Does the wire running from the positive side of the coil to Terminal 15 of the fuse block provide the keyed 12V connection? Part of the regular harness,
Or do I need to run an auxiliary wire from, say, the keyed post of the battery isolation solenoid to the positive terminal of the coil. (see photo with yellow wire)
I want to figure this out before I try to start it again.
Any speculation on what would happen if the engine was started with two sources of power to the coil?
They mystery wire.
The big question.
Thanks all,
dgsaz |
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jeffrey8164 Samba Member
Joined: January 06, 2018 Posts: 3817 Location: Georgia
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Posted: Fri Apr 23, 2021 2:44 pm Post subject: Re: Electric Question / Scrambled Eggs |
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Yes terminal 15 is also the positive side of the coil which should be powered when the key is turned to the on position. Did you run that extra wire for a possible tachometer that you never installed? Either way as long as the coil is getting 12 V with the ignition on you should be fine. It doesn’t really matter if it’s two wires or one wire as long as it’s key on power. All the voltage is essentially comes from the same place, the battery. If you have two wires that do the same thing it essentially is just making one wire a larger gauge. I know the older Pertronix units did not like constant voltage with the motor not running but I think the newer ones are immune to that. _________________ Volkswagen!
Turning owners into mechanics since 1938.
“Let he that is without oil throw the first rod”
(Compression 8.7:1) |
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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Fri Apr 23, 2021 3:03 pm Post subject: Re: Electric Question / Scrambled Eggs |
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jeffrey8164 wrote: |
Yes terminal 15 is also the positive side of the coil which should be powered when the key is turned to the on position. Did you run that extra wire for a possible tachometer that you never installed? Either way as long as the coil is getting 12 V with the ignition on you should be fine. It doesn’t really matter if it’s two wires or one wire as long as it’s key on power. All the voltage is essentially comes from the same place, the battery. If you have two wires that do the same thing it essentially is just making one wire a larger gauge. I know the older Pertronix units did not like constant voltage with the motor not running but I think the newer ones are immune to that. |
I installed a bank of gauges last year. There is a terminal in my Keyed Power
fuse box that feeds the gauges. Hummmmmm.......
That said, I'm not sure why I installed that yellow wire. Cross threaded thinking.
Just glad it I didn't burn anything up during the investigation.
Thanks,
dgsaz
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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Tue May 11, 2021 3:52 pm Post subject: Re: Electric Question / Scrambled Eggs |
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For anyone interested, I had a bad Pertronix, followed by a bad unit from the factory. I up graded to the Pertronix II and got the "Flamethrower" II coil. Now everything is in harmony and the bus runs great , again.
Now I have a new issue. No power to the bank of gauges in installed. I believe it to be the 3 pole solenoid. So I replaced it and still no power to the keyed power panel. Could I get two bad units in a row?
I think it's a bad solenoid from the store. Am I missing, what. Someone please point out the obvious. Thanks
dgsaz
Last edited by dgsaz on Wed May 12, 2021 11:39 am; edited 1 time in total |
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BarryL Samba Member
Joined: November 01, 2004 Posts: 14266 Location: Casa de Oro, California
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Posted: Tue May 11, 2021 6:40 pm Post subject: Re: Electric Question / Scrambled Eggs |
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Is the solenoid rated for continuous duty? |
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Help Help Samba Member
Joined: May 03, 2013 Posts: 117 Location: Running willy-nilly with scissors in So Cal
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Posted: Wed May 12, 2021 7:08 am Post subject: Re: Electric Question / Scrambled Eggs |
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Up front let me tell you that I don't have a leisure battery set up but I've been doing research.... and might be dropping one in this week.
From what I've read. . .
The standard circuits should be wired to primary battery like normal and the extra "leisure" circuits to the leisure battery. It's the charging circuit that should have the solenoid on it and be wired such that the batteries are only joined by the charging circuit when the car is running/charging. That way you can run the leisure battery into the dirt but still have your primary battery to start the car and drive home. |
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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Wed May 12, 2021 10:23 am Post subject: Re: Electric Question / Scrambled Eggs |
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Back to the solenoid.
Three pole solenoid. Primary battery to one terminal (large) Secondary to the other terminal.
The small center terminal connects to "12 volt accessory source activated by the ignition switch".
When the ignition is turned on, the solenoid "joins" the two batteries, when the ignition is off the two batteries are separate.
Here's my question:
When the key is on and the two batteries are working together, does the small terminal also provide a power source from the two batteries or is power from the coil (15) the only power available and acts just to activate the switch?
I want to power a small fuse block that is only on with the key. Does the small terminal work as a power source or is it just to activate the internals of the solenoid?
Can I use the small terminal as a power supply for my "keyed power" fuse block? Sorry about the babbling. Thanks
dgsaz |
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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Wed May 12, 2021 10:25 am Post subject: Re: Electric Question / Scrambled Eggs |
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Help Help wrote: |
Up front let me tell you that I don't have a leisure battery set up but I've been doing research.... and might be dropping one in this week.
From what I've read. . .
The standard circuits should be wired to primary battery like normal and the extra "leisure" circuits to the leisure battery. It's the charging circuit that should have the solenoid on it and be wired such that the batteries are only joined by the charging circuit when the car is running/charging. That way you can run the leisure battery into the dirt but still have your primary battery to start the car and drive home. |
I'm using the diagram in the photo below. |
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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Wed May 12, 2021 10:30 am Post subject: Re: Electric Question / Scrambled Eggs |
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BarryL wrote: |
Is the solenoid rated for continuous duty? |
Yes, continuous duty.
The solenoid was presented as a "battery isolator". |
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BarryL Samba Member
Joined: November 01, 2004 Posts: 14266 Location: Casa de Oro, California
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Posted: Wed May 12, 2021 11:40 am Post subject: Re: Electric Question / Scrambled Eggs |
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dgsaz wrote: |
Here's my question:
When the key is on and the two batteries are working together, does the small terminal also provide a power source from the two batteries or is power from the coil (15) the only power available and acts just to activate the switch? |
The small terminal activates the switch. The small terminal is going to a fine-wire coiled winding that magnetically pulls a metal bridge between the two large contacts.
dgsaz wrote: |
I want to power a small fuse block that is only on with the key. Does the small terminal work as a power source or is it just to activate the internals of the solenoid? |
Yes it is keyed power but you would be better off having the coil wire left alone going to the coil/choke/pilot and adding your own wire to #15 right from the ignition switch with a fused dedicated wire for your accessories' power.
dgsaz wrote: |
Can I use the small terminal as a power supply for my "keyed power" fuse block? Sorry about the babbling. Thanks
dgsaz |
You "can" be the guinea-pig and report how well it works. Theoretically if the coil wire has "headroom" to rob from it will work. |
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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Wed May 12, 2021 11:44 am Post subject: Re: Electric Question / Scrambled Eggs |
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I'm going to try this instead:
I still can't remember how I had the "keyed power" fuse block fed. This set up with the relay will work fine.
Any flaws in the design?
dgsaz |
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BarryL Samba Member
Joined: November 01, 2004 Posts: 14266 Location: Casa de Oro, California
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Posted: Wed May 12, 2021 11:47 am Post subject: Re: Electric Question / Scrambled Eggs |
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That is a workaround that is a good relay that won't rob power but make sure the relay is rated for your draw. |
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dgsaz Samba Member
Joined: November 04, 2008 Posts: 579 Location: Phoenix / San Diego
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Posted: Wed May 12, 2021 12:33 pm Post subject: Re: Electric Question / Scrambled Eggs |
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BarryL wrote: |
That is a workaround that is a good relay that won't rob power but make sure the relay is rated for your draw. |
The draw is minimal. Just the power and light circuit for 3 gauges.
Here's the final design.
thanks,
dgsaz |
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BarryL Samba Member
Joined: November 01, 2004 Posts: 14266 Location: Casa de Oro, California
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Posted: Thu May 13, 2021 10:02 am Post subject: Re: Electric Question / Scrambled Eggs |
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What are you using the second battery for? If you run either battery a lot lower than the other battery be advised that there can be a lot of current flow suddenly when the battery connector solenoid closes. This has the potential to create side effects. |
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