adding a charging fault light

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moparmat2000

moparmat2000

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Hi Y'all,

Since i dont have my instrument cluster completely back together, i decided to add some hidden non stock niceties. One of these is an alternator fault light.

I am using a mini denso alternator which has a spot on its built in regulator for an indicator light. It a pretty simple circuit. The light gets its power from an ign hot circuit, thru a light bulb or 12v led, then to the internal regulator.

When ignition is rotated on but engine not running, the regulator faults to ground lighting the light, once the engine is running and regulator and alternator are on line, light goes out. If the alternator faults during operation , this circuit shunts to ground turning the light on.

Anyway, i like the idea of a backup light indicator to go along with the gage. My gage is an ammeter converted to volt gage with a sun volt gage. I drilled a tiny #50 hole to the left of the D on the gage, and used JB weld to hold the 12V led in place on the back of the gage face. I soldered the positive wire for the led to the 12v feed stud on the gages internals, as thats the ign switched feed to the gage, and drilled a small hole in the cast metal gage housing to run the wire that will go out to the voltage regulator.

I like it because its bright enough to get your attention, but doesnt ruin the classic look of the rallye gage cluster with a big honkin LED. The pix dont do it justice as far as the brightness goes, it does get your attention though.

Matt
 

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A+! Where does it tie in on the alternator/regulator?
 
My mini denso has a 2 wire plug. Plus heavy output to battery terminal.

On the 2 wire plug its labelled IG for ignition in, thats ign switched hot to turn on the regulator,

The other spade is labelled L for indicator light. Thats where the wire from the indicator light goes.

If using an LED these are polarity sensitive, if you hook it up backwards it will not light.
 
If my charging system goes down my A/F gauge starts flashing "E9" which is the code for low voltage.
 
On the older Delcos, the lamp circuit is the "exciter." Originally it was lamp in parallel with a resistor, so if the bulb failed, it would still excite. Frankly I'm surprised that an LED would excite "all" Delcos. Might be a "one wire" regulator.

Many guys used to mistake using the older Delcos in a swap, leave out the lamp, and wire the no1 connector direct to the key. That might work once, twice, or 507 times, but some time or other, it will take out the diode trio. You must have a diode or resistor or lamp in the no1 lead to protect it.

Some of the later model Furies? and other sleds had a warning lamp for the charging system. I will have to look them up. Forget what was involved, there

EDIT cannot find the bloody thing. First year I see mention is 79, was evidently a solid state voltage indicator (light came on with low voltage) but the wiring diagrams have it pretty well hidden LOL
 
67Dart273 said:
On the older Delcos, the lamp circuit is the "exciter." Originally it was lamp in parallel with a resistor, so if the bulb failed, it would still excite. Frankly I'm surprised that an LED would excite "all" Delcos. Might be a "one wire" regulator.

Many guys used to mistake using the older Delcos in a swap, leave out the lamp, and wire the no1 connector direct to the key. That might work once, twice, or 507 times, but some time or other, it will take out the diode trio. You must have a diode or resistor or lamp in the no1 lead to protect it.

Some of the later model Furies? and other sleds had a warning lamp for the charging system. I will have to look them up. Forget what was involved, there
Click to expand...

I have read up on installing and wiring a mini denso. The indicator light is not part of the exciter, therefore it doesnt need to be an incandescent bulb.

Your Ignition in hot wire takes care of that. It appears that the denso warning light just goes from an Ignition on hot source to a light , then to the connector on the alternator marked L for light. None of the schematics i have seen to wire up a denso setup show a resistor in parallel with the light. I did a lot reading and research as to how to hook one of these densos up. The light circuit is not required to run it.

But i am assuming you are talking about just old delco alternators wired this way.
 
moparmat2000 said:
I have read up on installing and wiring a mini denso. The indicator light is not part of the exciter, therefore it doesnt need to be an incandescent bulb.

Your Ignition in hot wire takes care of that. It appears that the denso warning light just goes from an Ignition on hot source to a light , then to the connector on the alternator marked L for light. None of the schematics i have seen to wire up a denso setup show a resistor in parallel with the light. I did a lot reading and research as to how to hook one of these densos up. The light circuit is not required to run it.

But i am assuming you are talking about just old delco alternators wired this way.
Click to expand...

That's good to know. I haven't run one of those as yet Nice idea, in any case
 
Im running a low mouont Sprint mini denso alternator on my stroker and it has the same connector in the plug for a charge light too. Now Im going to utilize it, thanks for the idea!
 
Interesting info. My 1980's M-B cars have the Motorola-type alternator (Bosch), same as older GM. As mentioned, the light provides current to boot-up the internal generator (a mini-alternator) that powers the internal Vreg. They feed the D+ terminal. If the bulb didn't light when you first turn the key, the owner's manual said to immediately drive to a dealer for an emergency bulb replacement (how many M-B techs does it take to change a light bulb? and how much would they charge?). Actually 3 dash lamps supply that current in my M-B's. When I changed to LED's in the dash, I found they wouldn't go out at idle, because they don't conduct enough current for boot-up. But, once I rev to 1000 rpm, they go out because in older alternators, there is enough residual magnetism to self-generate at higher speed. I carry a 1000 ohm resistor to use for emergency bootup if enough LED's fail. Good that the Denso alternators aren't like this and that wire is strictly for an indicator. The Motorola design was endlessly confusing to owners.
 
Yep everything i have seen and read about so far shows the light circuit to be an indicator only, and not part of the exciter. Its gonna be awhile before i get to test this. Now if thats not true, i can always put a lightbulb or a small resistor in parallel in the circuit to get it to do what its supposed to do. Anybody hazard a guess what ohm resistance resistor i would need?

Matt
 
So what kind of alternator do 5.2/5.9 magnum mills use?

My '93 Cummins Ram? The ram is a pita because the regulator is in the pcm and they fail every year the royals don't win a world series.
 
67Dart273, im thinking it should be able to put a light on our mopars with some wiring changes, maybe a diode? Im drawing some diagrams that look like it will work. What do you think?
Edit: Im thinking a relay that will drop out when ALT stops charging, lighting the light.
 
Mopar Tim said:
67Dart273, im thinking it should be able to put a light on our mopars with some wiring changes, maybe a diode? Im drawing some diagrams that look like it will work. What do you think?
Edit: Im thinking a relay that will drop out when ALT stops charging, lighting the light.
Click to expand...

I realize you asked Del, but I have to think the relay won't do it on it's own because the battery would feed it anyway.
Maybe a voltage threshold type device, so ANY time the voltage was below say 13 volts it would trigger the light?
(adjustable voltage threshold would be nice)

The Arduino controllers could do this easily.
 
moparmat2000 said:
Hi Y'all,

Since i dont have my instrument cluster completely back together, i decided to add some hidden non stock niceties. One of these is an alternator fault light.

I am using a mini denso alternator which has a spot on its built in regulator for an indicator light. It a pretty simple circuit. The light gets its power from an ign hot circuit, thru a light bulb or 12v led, then to the internal regulator.

When ignition is rotated on but engine not running, the regulator faults to ground lighting the light, once the engine is running and regulator and alternator are on line, light goes out. If the alternator faults during operation , this circuit shunts to ground turning the light on.

Anyway, i like the idea of a backup light indicator to go along with the gage. My gage is an ammeter converted to volt gage with a sun volt gage. I drilled a tiny #50 hole to the left of the D on the gage, and used JB weld to hold the 12V led in place on the back of the gage face. I soldered the positive wire for the led to the 12v feed stud on the gages internals, as thats the ign switched feed to the gage, and drilled a small hole in the cast metal gage housing to run the wire that will go out to the voltage regulator.

I like it because its bright enough to get your attention, but doesnt ruin the classic look of the rallye gage cluster with a big honkin LED. The pix dont do it justice as far as the brightness goes, it does get your attention though.

Matt
Click to expand...

Matt,
Wowwwwwwwwwwwwwwwww!! that is the coolest thing ever, I mean EVER! Do you have a part number of the Alternator and the Battery Gauge? how many volts does it take to trip the light on?

If there was a coolest award you would get it.... any pictures of the alternator?
 
64_Barracuda said:
Matt,
Wowwwwwwwwwwwwwwwww!! that is the coolest thing ever, I mean EVER! Do you have a part number of the Alternator and the Battery Gauge? how many volts does it take to trip the light on?

If there was a coolest award you would get it.... any pictures of the alternator?
Click to expand...

I used a sunpro instruments CP8215 volt gage, and used just its guts. Reinstalled my ammeter face after modifying it to fit. This was a mod shown elsewhere on fabo i just copied what was done.

I drilled out the old ammeter gage mounting holes in the gage housing and installed plastic grommets that came with the sunpro gage to insulate both studs. The ground stud i shimmed with a nut and washer and made sure it grounded to the gage housing. The positive stud you can see in the pic has a red plastic insulator

On the back side of the gage housing i made a 14g jumper wire from the volt gage positive stud to the 12V input for the initial gage feed from the wiring harness. This way it has power, and case ground. The pic shows a black ground wire i have since eliminated since the gage is now case ground. Only the red lead remains.

The alternator is a mini nippondenso 50A. Which required an 8 ga wire as output. This required removal of the original ammeter and wiring as 8 gage wasnt going to fit the bulkhead connector, and i wasnt going to put a major hot lead thru my firewall in a grommet.

I modded the ammeter circuit, and sent dual leads from the bulkhead that were for the ammeter and dash feed both straight to the battery with a fusable link at the battery. Actually tied them in at the starter relay lug.

Then my alternator 8 ga lead went straight to the battery with its own fusable link.

I could take a crapload of pix and post em up here, but with my upload rate, and resizing them some of the detail will be lost making it a bit hard to figure out.

Here is an alternator mounting pic though. The alt cost ne $87 new, is a 50A and weighs about 5 Lbs, and the 1/8" thick custom made brackets are 7475 T6 aluminum plate and weigh about 12 oz. Spacer was trimmed out of steel blackpipe from home depot to remove the threaded ends, then trued up on a lathe at work. The spacer for the adjustor strap to the lower alternator mount is a machine turned down aluminum spacer made from a SAAB 340 B aircraft overhead bin spacer, though anything could be turned down to be used. The adjuster bolt is 13mm which i left insteadbof tapping for SAE thread since a 1/2" wrench will fit a 13mm.

Heres sideways and upside down pix again lol.
 

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moparmat2000 said:
I used a sunpro instruments CP8215 volt gage, and used just its guts. Reinstalled my ammeter face after modifying it to fit. This was a mod shown elsewhere on fabo i just copied what was done.

I drilled out the old ammeter gage mounting holes in the gage housing and installed plastic grommets that came with the sunpro gage to insulate both studs. The ground stud i shimmed with a nut and washer and made sure it grounded to the gage housing. The positive stud you can see in the pic has a red plastic insulator

On the back side of the gage housing i made a 14g jumper wire from the volt gage positive stud to the 12V input for the initial gage feed from the wiring harness. This way it has power, and case ground. The pic shows a black ground wire i have since eliminated since the gage is now case ground. Only the red lead remains.

The alternator is a mini nippondenso 50A. Which required an 8 ga wire as output. This required removal of the original ammeter and wiring as 8 gage wasnt going to fit the bulkhead connector, and i wasnt going to put a major hot lead thru my firewall in a grommet.

I modded the ammeter circuit, and sent dual leads from the bulkhead that were for the ammeter and dash feed both straight to the battery with a fusable link at the battery. Actually tied them in at the starter relay lug.

Then my alternator 8 ga lead went straight to the battery with its own fusable link.

I could take a crapload of pix and post em up here, but with my upload rate, and resizing them some of the detail will be lost making it a bit hard to figure out.

Here is an alternator mounting pic though. The alt cost ne $87 new, is a 50A and weighs about 5 Lbs, and the 1/8" thick custom made brackets are 7475 T6 aluminum plate and weigh about 12 oz. Spacer was trimmed out of steel blackpipe from home depot to remove the threaded ends, then trued up on a lathe at work. The spacer for the adjustor strap to the lower alternator mount is a machine turned down aluminum spacer made from a SAAB 340 B aircraft overhead bin spacer, though anything could be turned down to be used. The adjuster bolt is 13mm which i left insteadbof tapping for SAE thread since a 1/2" wrench will fit a 13mm.

Heres sideways and upside down pix again lol.
Click to expand...

Neat, what VDC does the light come on at?
 
TrailBeast said:
I realize you asked Del, but I have to think the relay won't do it on it's own because the battery would feed it anyway.
Maybe a voltage threshold type device, so ANY time the voltage was below say 13 volts it would trigger the light?
(adjustable voltage threshold would be nice)

The Arduino controllers could do this easily.
Click to expand...
My thinking. thank You could use a veristat to control voltage on a test bench. lower it till a 12v relay cut out, read the total resistance on the veristat, and put in a resistor of the same value. When voltage goes below threshold relay drops out. Of course power the test circuit with the Same voltage a Alt puts out under load at Idle.
 
If on a typical alternator , the sense wire is needed with the resistance of a light bulb to get the regulator to start charging, couldent you run a 14 ga wire with a 470 ohm 5 or 10 W resistor to make the alternator think its a light bulb, , then if you wanted an LED indicator light, just wire it in parallel to the resistor with the negative side of the LED going towards the alternator. Since they only light in one direction polarity wise wouldent a setup like this work. I mean some of y'all are talking about diodes. Rectifiers, relays etc to make the light come on and go out. Do you think maybe your over thinking it a bit, or am i just under thinking it.

Matt
 
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