The Ford Barn

OL JENNY · 03-20-2015, 07:08 PM

I am still trying to think through some type of audio warning for lights being left on. On a Model A with a 6 volt alternator is there anywhere in the wiring where it is only hot when the engine is running. I have seen the posts that work with a generator by connecting ahead of the cutout, but I don't seem to think of a similar type location on a one post 6 volt alternator. I will probably settle for a little LED that is on when the headlights are on. Usually I have only forgot them when using the lights for daytime driving. Thanks for taking a look at the post.

MikeK · 03-20-2015, 09:35 PM

Not on a one-wire alternator if you have the original ignition wiring: Batt to coil to switch to points. If you have changed wiring to switch the coil on/off it is a simple high z relay or switching transistor between that point and the tail lamp feed.

If you have an alternator with an "L" terminal (lamp) AND the alternator is not wired to produce an output polarity opposite what the "L" terminal can sink, you could place a piezo buzzer between the tail lamp feed and the "L" terminal. Keep in mind piezos are polarity sensitive. To put that in simpler terms, it will work with a neg. ground 3 wire alternator, but not with most one-wire nor any positive ground alternators based on the old Delco 10/12SI design.

If you understand what is inside any alternator regulator you can split it open and add a MOSFET to switch a reminder buzzer on when the drive to the rotor falls to zero.

There are other external ways for a 6V+ one-wire vehicle, but not do-it-yourself easy. You could build a voltage comparator circuit that would switch on/off just above battery voltage. You could place a sensor, like a Hall or photo beam to detect engine rotation and use it to constantly reset a delay timer that keeps the buzzer off. You could build a waveform monitor to detect ignition activity, etc, etc. Get some TTL and CMOS cookbooks and have fun.

Mike V. Florida · 03-20-2015, 11:31 PM

I guess you could get used to looking at the ammeter, as it will indicate the lights being on.

I thinking out loud here but an electronic hobbyist could come up with a light replacement for the ammeter. It could show one color for charge and one for discharge. With the car off the"meter" lights would be off and if the headlamps are on it would be lit..

Willie Krash · 03-20-2015, 11:44 PM

You could bring a wire off a stator terminal and feed it out the hole by the #2 or F terminal or better yet mount an insulated stud there (they make a kit) and you would scab off about 3.5V of quasi DC. It will have the properties of DC. Now you would have to find a 3-4 V relay and tie that to a buzzer or sonalert. The stator tap would open the points when the car is running and when the alt stopped outputting if the lights are on the buzzer will sound. I think I'm good here, will have another glass of wine and think on it...

Context, this is often done on industrial equipment to feed hobbs meters, etc.
The stator tap can take a lot of electrical abuse where diode trio (L-term) not so much.

OL JENNY · 03-21-2015, 08:23 AM

Thanks to all who have replied, this gives considerable food for thought. Remembering or a small indicator light starts to look better all the time.

Bob C · 03-21-2015, 11:46 AM

Sponsored Links (Register now to hide all advertisements)

Just looking at the ammeter when you get out of the car is a good habit.
It will let you know if the cut out is stuck, brake light switch it stuck or
the head light are on.

Bob

Jacksonlll · 03-21-2015, 01:38 PM

I had that problem when using the lights in the day time and then parking. I have a roadster. I installed a brake light switch in the door jam. The door pushes the plunger in as it closes. I then took power from the tail light circuit to the switch, then from the switch to a 6 volt buzzer I got at Radio Shack and then to ground. When the lights are on and the switch plunger is out, the buzzer goes. jack

03-20-2015, 07:08 PM	#1
OL JENNY Senior Member Join Date: Sep 2012 Location: Muscatine, IA Posts: 223	Hot Wire Question I am still trying to think through some type of audio warning for lights being left on. On a Model A with a 6 volt alternator is there anywhere in the wiring where it is only hot when the engine is running. I have seen the posts that work with a generator by connecting ahead of the cutout, but I don't seem to think of a similar type location on a one post 6 volt alternator. I will probably settle for a little LED that is on when the headlights are on. Usually I have only forgot them when using the lights for daytime driving. Thanks for taking a look at the post.

03-20-2015, 11:31 PM	#3
Mike V. Florida Senior Member Join Date: May 2010 Location: South Florida Posts: 14,054	Re: Hot Wire Question I guess you could get used to looking at the ammeter, as it will indicate the lights being on. I thinking out loud here but an electronic hobbyist could come up with a light replacement for the ammeter. It could show one color for charge and one for discharge. With the car off the"meter" lights would be off and if the headlamps are on it would be lit.. __________________ What's right about America is that although we have a mess of problems, we have great capacity - intellect and resources - to do some thing about them. - Henry Ford II

03-20-2015, 11:44 PM	#4
Willie Krash Senior Member Join Date: Jan 2012 Location: Phoenix, Oregon Posts: 661	Re: Hot Wire Question You could bring a wire off a stator terminal and feed it out the hole by the #2 or F terminal or better yet mount an insulated stud there (they make a kit) and you would scab off about 3.5V of quasi DC. It will have the properties of DC. Now you would have to find a 3-4 V relay and tie that to a buzzer or sonalert. The stator tap would open the points when the car is running and when the alt stopped outputting if the lights are on the buzzer will sound. I think I'm good here, will have another glass of wine and think on it... Context, this is often done on industrial equipment to feed hobbs meters, etc. The stator tap can take a lot of electrical abuse where diode trio (L-term) not so much. __________________ Mike Stitt "A business that make nothing but money is a poor business." -Henry Ford

03-21-2015, 08:23 AM	#5
OL JENNY Senior Member Join Date: Sep 2012 Location: Muscatine, IA Posts: 223	Re: Hot Wire Question Thanks to all who have replied, this gives considerable food for thought. Remembering or a small indicator light starts to look better all the time.

03-21-2015, 11:46 AM	#6
Bob C Senior Member Join Date: May 2010 Location: So Cal Posts: 8,766	Re: Hot Wire Question Sponsored Links (Register now to hide all advertisements) Just looking at the ammeter when you get out of the car is a good habit. It will let you know if the cut out is stuck, brake light switch it stuck or the head light are on. Bob

03-20-2015, 09:35 PM	#2
MikeK Senior Member Join Date: May 2010 Location: Windy City Posts: 2,919	Re: Hot Wire Question Not on a one-wire alternator if you have the original ignition wiring: Batt to coil to switch to points. If you have changed wiring to switch the coil on/off it is a simple high z relay or switching transistor between that point and the tail lamp feed. If you have an alternator with an "L" terminal (lamp) AND the alternator is not wired to produce an output polarity opposite what the "L" terminal can sink, you could place a piezo buzzer between the tail lamp feed and the "L" terminal. Keep in mind piezos are polarity sensitive. To put that in simpler terms, it will work with a neg. ground 3 wire alternator, but not with most one-wire nor any positive ground alternators based on the old Delco 10/12SI design. If you understand what is inside any alternator regulator you can split it open and add a MOSFET to switch a reminder buzzer on when the drive to the rotor falls to zero. There are other external ways for a 6V+ one-wire vehicle, but not do-it-yourself easy. You could build a voltage comparator circuit that would switch on/off just above battery voltage. You could place a sensor, like a Hall or photo beam to detect engine rotation and use it to constantly reset a delay timer that keeps the buzzer off. You could build a waveform monitor to detect ignition activity, etc, etc. Get some TTL and CMOS cookbooks and have fun.

03-21-2015, 01:38 PM	#7
Jacksonlll Senior Member Join Date: Jul 2012 Location: Michigan-- Member of Oakleaf of MARC Posts: 1,686	Re: Hot Wire Question I had that problem when using the lights in the day time and then parking. I have a roadster. I installed a brake light switch in the door jam. The door pushes the plunger in as it closes. I then took power from the tail light circuit to the switch, then from the switch to a 6 volt buzzer I got at Radio Shack and then to ground. When the lights are on and the switch plunger is out, the buzzer goes. jack