Battery cut-off and 1-wire alternator

[denpo]

I got one of those to install on my project.

Its sole purpose it to remove *ANY* electrical activity from the car when in storage.
My initial though was to put it between the + of the battery and the rest of the car.

After some research turns out when used with 1-wire alternator (like my 100a upgrade), you'd need a wiring like this one.

I don't get why you need to keep on powering the alternator.

 

[mrvette]

YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars.....:shocking:

 

[SuperBuickGuy]

YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars.....:shocking:

I agree that you don't need that wire. You do need to wire your alternator in like that if you're drag racing and have relocated the battery to the trunk. That schematic turns power off to the entire electrical system (so that the alternator doesn't keep the motor running when the kill switch is activated). But, again, for storage and no drain, that would actually defeat the purpose because it'd keep the field charged at all times.

 

[denpo]

YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars.....:shocking:

I agree that you don't need that wire. You do need to wire your alternator in like that if you're drag racing and have relocated the battery to the trunk. That schematic turns power off to the entire electrical system (so that the alternator doesn't keep the motor running when the kill switch is activated). But, again, for storage and no drain, that would actually defeat the purpose because it'd keep the field charged at all times.

Yeah, that was my very concern.
Thanks for the answers guys :beer:

 

[mrvette]

YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars.....:shocking:

I agree that you don't need that wire. You do need to wire your alternator in like that if you're drag racing and have relocated the battery to the trunk. That schematic turns power off to the entire electrical system (so that the alternator doesn't keep the motor running when the kill switch is activated). But, again, for storage and no drain, that would actually defeat the purpose because it'd keep the field charged at all times.

Yeah, that was my very concern.
Thanks for the answers guys :beer:

No it won't, not with the typical GM alts I have dealt with over years....

that +12 main out stud is always live.....

now the L connection on a later alternator is a switched animal, and so will deactivate the regulator when the ign sw turns off the power to the bulb, or resistor wire substitute in a later shark....the load of the bulb when lit is only say .5 amps....:shocking:

 

[SuperBuickGuy]

YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars.....:shocking:

I agree that you don't need that wire. You do need to wire your alternator in like that if you're drag racing and have relocated the battery to the trunk. That schematic turns power off to the entire electrical system (so that the alternator doesn't keep the motor running when the kill switch is activated). But, again, for storage and no drain, that would actually defeat the purpose because it'd keep the field charged at all times.

Yeah, that was my very concern.
Thanks for the answers guys :beer:

No it won't, not with the typical GM alts I have dealt with over years....

that +12 main out stud is always live.....

now the L connection on a later alternator is a switched animal, and so will deactivate the regulator when the ign sw turns off the power to the bulb, or resistor wire substitute in a later shark....the load of the bulb when lit is only say .5 amps....:shocking:

one wire alternator - there is no resister wire.... the charge field is generated by a resistor that is supposed to prevent bleed from happening. That is why you need to get above 1500 rpm for a one-wire to start charging... but, you will have to trust me on this one - it is possible for the alternator to still be pulling a charge - thus, my advice to avoid that schematic unless he needs a cut-off switch per rules for whatever he races.

seriously man, I expected at least "d'oh" when you realized you were 100% wrong with this classic line "YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars"

 

[mrvette]

YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars.....:shocking:

I agree that you don't need that wire. You do need to wire your alternator in like that if you're drag racing and have relocated the battery to the trunk. That schematic turns power off to the entire electrical system (so that the alternator doesn't keep the motor running when the kill switch is activated). But, again, for storage and no drain, that would actually defeat the purpose because it'd keep the field charged at all times.

Yeah, that was my very concern.
Thanks for the answers guys :beer:

No it won't, not with the typical GM alts I have dealt with over years....

that +12 main out stud is always live.....

now the L connection on a later alternator is a switched animal, and so will deactivate the regulator when the ign sw turns off the power to the bulb, or resistor wire substitute in a later shark....the load of the bulb when lit is only say .5 amps....:shocking:

one wire alternator - there is no resister wire.... the charge field is generated by a resistor that is supposed to prevent bleed from happening. That is why you need to get above 1500 rpm for a one-wire to start charging... but, you will have to trust me on this one - it is possible for the alternator to still be pulling a charge - thus, my advice to avoid that schematic unless he needs a cut-off switch per rules for whatever he races.

seriously man, I expected at least "d'oh" when you realized you were 100% wrong with this classic line "YOU don't, that schematic is bullshit, who ever drew it up, knows nothing of cars"

Totally disagree with you, BTDT, proved my case years ago, and so to wait for 69427 Mike to settle the issue.....:shocking:

The internal regulator is set to disable any field or other battery load via internal zener/regulator wiring, and so IF there is no regulator hookup on our old SI series the Alt has to see some 1500 engine rpm to make a charge output...the genre of the one wire is from marine use, where engines typically easy see 1500 rpm almost all the time....and maybe even have different drive ratios,

I have modified SI series alts for marine useage, BTDT years ago, put one on a Volvo powered boat when the OEM flipped out....and had to call my EE old FIL to ask a couple tech questions he answered quick because he did the war on HIS boat.....the only terminal that needs be hot is the RED wire off the aftermarket connectors, I unsure of what a old vette was, have to go to the diagrams, but it's the MOST clockwise term when viewing from the back of the alt/engine...

the regulator is set so if the rpm is too low it lights the lite, nothing new there, except Vettes had a Resistor wire to simulate the bulb, and no bulb, but a useless amp meter instead.....another discussion.....:shocking:

 

[turtlevette]

switched systems put the field on as soon as you turn on the ignition.

One wire systems have a sophisticated system that recognizes when the engine is starting and when it has stopped to turn the field on/off. Voltage deltas and thresholds as well as a ripple detect.

 

[mrvette]

switched systems put the field on as soon as you turn on the ignition.

One wire systems have a sophisticated system that recognizes when the engine is starting and when it has stopped to turn the field on/off. Voltage deltas and thresholds as well as a ripple detect.

:shocking: You stated it better, I agree, what you said.....:beer::shocking:

 

[rtj]

That's how you have to wire a drag car. They need to be able to kill the power with one kill switch.

 

[denpo]

That's how you have to wire a drag car. They need to be able to kill the power with one kill switch.

I think I understand now, leaving the alternator connected keep the regulator active.
I might not need a switch that to kill the car, but what if the switch goes off by accident while the car still running? The alternator would go in dump load mode and fry the car electronic.

 

[mrvette]

That's how you have to wire a drag car. They need to be able to kill the power with one kill switch.

I think I understand now, leaving the alternator connected keep the regulator active.
I might not need a switch that to kill the car, but what if the switch goes off by accident while the car still running? The alternator would go in dump load mode and fry the car electronic.

:shocking: NEVER seen one do that.....60 years now.....

course I don't go pulling bat cables on running cars ever day either, I do forward trouble shooting, not backwards.....

:harhar::1st:

 

[denpo]

That's how you have to wire a drag car. They need to be able to kill the power with one kill switch.

I think I understand now, leaving the alternator connected keep the regulator active.
I might not need a switch that to kill the car, but what if the switch goes off by accident while the car still running? The alternator would go in dump load mode and fry the car electronic.

:shocking: NEVER seen one do that.....60 years now.....

course I don't go pulling bat cables on running cars ever day either, I do forward trouble shooting, not backwards.....

:harhar::1st:

Of course, that the kind of event you NEVER want to happen, and I'm glad it didn't happen to you, but you can't just rule them out.

 

[mrvette]

That's how you have to wire a drag car. They need to be able to kill the power with one kill switch.

I think I understand now, leaving the alternator connected keep the regulator active.
I might not need a switch that to kill the car, but what if the switch goes off by accident while the car still running? The alternator would go in dump load mode and fry the car electronic.

:shocking: NEVER seen one do that.....60 years now.....

course I don't go pulling bat cables on running cars ever day either, I do forward trouble shooting, not backwards.....

:harhar::1st:

Of course, that the kind of event you NEVER want to happen, and I'm glad it didn't happen to you, but you can't just rule them out.

:shocking: Couple of years ago, and I leaned my metal watch band against the alt out stud and alt frame.....

needless to say it branded me, but no worse than on my right arm from headers.....I show the scars someday....:harhar:

 

[big2bird]

I got one of those to install on my project.

Its sole purpose it to remove *ANY* electrical activity from the car when in storage.
My initial though was to put it between the + of the battery and the rest of the car.

After some research turns out when used with 1-wire alternator (like my 100a upgrade), you'd need a wiring like this one.

I don't get why you need to keep on powering the alternator.

Denis. Put the switch immediately after the battery. It's for storage, not emergencies.

 

[denpo]

Denis. Put the switch immediately after the battery. It's for storage, not emergencies.

Your remark puts me in front of my own inconsistency : I want a storage cut off but I buy a show-off switch.
I should have a cutoff at the battery post, one that can't fail and can't be operated by some monkeys while running, and if I want, put the flashy red one on the dash, with the extra wire.

 

[MYBAD79]

your battery is in the stock location ?

I relocated my battery to the front passenger side under the hood.... one of my near future projects is a "kill switch extension" so that I dont have to pop the hood everytime I want to get to the switch.....
:smash:

 

[Garys 68]

I put them on all the cars I work on. Easy to disconnect the battery when wrenching. On the vette, it's in that center storage area right next to the battery.

 

[Bullshark]

switched systems put the field on as soon as you turn on the ignition.

One wire systems have a sophisticated system that recognizes when the engine is starting and when it has stopped to turn the field on/off. Voltage deltas and thresholds as well as a ripple detect.

Sophisticated??? Don't they just depend on leakage current thru the regulator transistors to turn on the field current rather than the sense voltage.

 

[fastcompany2]

don't use that switch. your diagram is right that you posted at the beginning but it will kill your battery. you need to use this switch. https://www.pegasusautoracing.com/productdetails.asp?RecID=1464 i don't know why they even sell other ones. this is the only truly safe one that wont kill your battery or hurt your alt. oh and if your worried about where to mount the switch what we always do is mount it where it is out of the way and hook a choke cable up to it so it can be switched off easy while the driver is strapped into the car.