Dodge voltage regulator...

knockbill

Lunatic Member
Anyone ever design or build an adjustable VR for a car/truck? I've been trying to get the charging Voltage down in an old van using the regulators from the auto parts stores,,, but they all see to be cheap knock offs,, and hold the voltage at 15-15.1 Volts,,, not good for lights, ignition systems, motors, batteries, etc... Figured it may be easier to build one that actually worked, with help here!!!
Thanks for any input...
 
Unless you are talking about an old car, you could just go to the dealer and get a good one. I too have had problems with volt regulators (and starters, alternators, sending units, you name it) from auto parts stores. Seems like for every good one there are 3 bad! But they are cheap anyway..
 
Its for an 86 van,,, its just old enough for decent parts not to be stocked, but there is a lot of junk "new parts" on the market,,, The new VRs are considered "in spec" at 15V,,, which is dangerously high for the motors, lights, ignition etc on this truck, which specs 13.9 to 14.6VDC...
Figured it may be an interesting project...
 
Where does the voltage reference feed come from? If its straight off the battery, you can fake it some by pulling it straight off the alternator. That will let the drop between the alternator and battery put you back where it belongs.

Worth checking voltage drop on both the ground and hot side though, alternator case to battery and charge output stud to battery. I had problems with something on the Towncar, turns out it was a bad connection between the alt case and the bracket. Might not be a bad idea to measure the voltage drop on the regulator's + and - for the same reason. If the ground is crusty there it will over-charge.
 
There used to be a company that made them for at least European alternators. I had one on a VW Corrado to kick the headlight brightness up a little, along with a 12AWG wiring harness with relays and E-code reflectors. I can't remember the name to save my life though.
 
Just came to me. Transpo was the company.

Also if this is a really old van with an electromechanical regulator, those are all adjustable if you know what you're doing :)
 
Comes from battery, thru fuseable link which also feeds all memory stuff and ignition key power then to B+ terminal on alt, which field feeds Ignition terminal on reg,,, I install a bunch of redundant grounds on this van years ago when it had an intermittent problem in the dash,,, really not depending on chassis, case grounds, frame grounds,,, Rust ain't good comductor!

I found an easy resistance check for these prolific VRs,,, figure I'll look at some on old junkers and check em.... Seems the new replacement VRs are all made to the same spec which is considered good to 15VDC... I tried three new ones,,, best one measured 15.06, heater motor screams like a banshee...
 
This one uses a SS reg,,, but is close to last one without FI, computers and the extra load they need... But there only seems to be one "fits all" VR available now... I saw Summit has an adjustable VR but its rated racing only, what ever that means!!
 
It's funny that you're trying to turn it down, euro cars seem to sit right at 13.7V or even lower so we were always trying to bump it to 14.1-14.3
 
Yep,,, I replaced the alt also, and rebuilt the charging harness... Guess it was happier with the couple strands of wire left feeding the fuseable link!!! That and the redundant grounds don't allow for the high resistance connection Dodge allowed for in the design!!!!
Maybe removing the ground wires and just using the chassis/frame grounds would allow the voltage drop it requires to be in spec...
 
try a Ford voltage regulator maybe. They usually struggle to get much past 14 volts. If yours has the usual idiot light, battery sense, field, and stator connections a Ford one should drop right in if you make up a little adapter harness to go from the Chrysler connector to the Ford one. I don't think I've ever run a non-OE one though so no clue what those might do. The one on the Mark VII is original. I don't honestly know what the Continental has, it works so I never paid much mind to it.
 
That's a lot of voltage those aftermarket regulators are putting out!
I'd agree that it needs to be knocked down a little bit or you're going to be going through bulbs and motors like crazy.

I really don't have any ideas on how to do it aside from recommending a junkyard to scoop up as many good regulators as you can.
I did that for my '91 Ranger as they seem to have started to thin out at the yards these days. I loaded up on blower resistors, washer pumps, relays, and a bunch of other things I can't remember right now. The best part is when you carry your haul to the window to pay, the counter person looks at the sad bunch of stuff you've collected and usually just tells you to get going.
I've now got quite the collection of good junk so I should be set for a while.
 
Dodge VR wiring is just a B+ off the alt, then thru the field to Negative on the regulator,,, case is grounded...
http://www.mopar1.us/moparpost70.gif

I have some GM regulators, and thought about trying one of them, they are mechanical so can be adjusted... Or either testing some originals at a junk yard,, or lastly trying to build one... Maybe I removed too much fuseable link when I spliced the damaged alt B+ feed, and lowered the resistance in it, but I don't think so... I can try a longer piece and see if it drops any V...
 
80's Dodge and Chrysler electrical systems are strange. From the late 70's to the late 80's the company I worked for used dodge vehicles. We would catch holy hell if we didn't keep extra electronic ignition boxes, voltage regulators and ballast resistors in the glove box. It didn't matter if they were from the dealer or after market, they just did not last. And those gear reduction starters!
 
They aren't that bad its just parts available today,,, I had this truck 30 years,,, changed one starter a one alt/reg before this one... It let me down once in that time,,, Starter crapped out in a parking lot a mile from home, walked home, got a new one and had at swapped out in half an hour!!!!

Still haven't sorted this overcharging problem, but now I know how to check a regulator with a simple resistance test, to confirm potential output V before I leave a store with it!!!! Still have to locate a decent one, tho... Its been raining all week, and for the next few days,,, not a good junk yard day!!!!This may help someone avoid the problem I had,,,

 
Is there a ballast resistor or two? Those burned out the most with the regulator being second. To be fair these were dodge fleet trucks. If the regulators weren't potted it would be easy to repair.
 
No,, Its an 86,,, a few years after points ignitions, but just before FI and computers... never had a ignition problem with this,,, just changed caps, rotors, plugs and wires occasionally... Yep,,, I think it would be fairly easy to repair, or add an adjustment pot to this, if it wasn't epoxy potted... Its noon here now so the real parts places are closed...

That was the purpose of this thread,,, wondered if possible to just build one with decent parts, that would be adjustable,,, They used to have them available after market,,, I never ran into this problem before... but who keeps a work truck this long!!!!!!
 
Ah, yes--the infamous ballast resistors--they should have included spares of those in the kit with the spare fuses. You were more likely to have one of them fail than an actual fuse in the fuseblock.
Our trucks used the single ballast resistors. So we would bolt the dual ones in place of the singles. When they failed we just had to move the connectors to the other side. @knockbill The older ones had a soft translucent rubbery potting material. It was easier to dig it out to see what the part values were.
 
Interesting,,, I got one of those in my hands!!! I'll start digging, and get back to ya! It tests open... They exist tho, look at the link!!,....
 
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