Add a resistor to one of the wires to the field coil? That's how the old mechanical regulators worked. There was just a relay type thing, and a couple resistors. All it does is adjust the current to the field coil. I don't really have a suggestion for a value though. The resistors weren't very big, so I doubt you'll need a real high wattage one.
Dodge voltage regulator...
- Thread starter knockbill
- Start date
knockbill
Lunatic Member
Got it opened up... can't tell if a couple resistors are missing, but I didn't find them stuck in the RTV... The biggest chip at one end looks like the middle terminal is broken/burned off also... This VR was the original that was replaced along with the new alt... It tested open, as did the two new VRs I tried, according to the test link I posted...
Going to see if I can find a schematic with the board number...
Going to see if I can find a schematic with the board number...
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Djcoolray
Addicted Member
Mopar.com....
I would just get the right parts to begin with and save the headaches, time and frustration. I’ve heard about after market alternators having power surges that blow out cheap replacement parts. I would order an alternator, VR and ballast resistors and check all the grounds to make sure they’re clean.
The best Dodge van is a B-series early seventies unibody with a 225 engine, add iridium spark plugs and a magnaflow muffler to get impressive gas mileage. If your going to have to work on something it should be something to your benefit.
Good luck....
I would just get the right parts to begin with and save the headaches, time and frustration. I’ve heard about after market alternators having power surges that blow out cheap replacement parts. I would order an alternator, VR and ballast resistors and check all the grounds to make sure they’re clean.
The best Dodge van is a B-series early seventies unibody with a 225 engine, add iridium spark plugs and a magnaflow muffler to get impressive gas mileage. If your going to have to work on something it should be something to your benefit.
Good luck....
knockbill
Lunatic Member
I have a couple mechanical regulators,,, GM tho... easy enough to measure the resistor to the field relay...
knockbill
Lunatic Member
Sounds like a plan,,, gotta time machine ,,, site only goes back to 2001
I've replaced many voltage regulators on that type charging system and the cheap electronic regulators were good at roughly 14.2 volts, depending on temperature... colder regulator temps produce higher charging voltage. It is absolutely necessary to have good ground connection from battery to chassis and from regulator to chassis... check for voltage drop under load between battery post, not clamp, and chassis and engine... should be a few millivolts... be sure of good battery negative to chassis connection.
Djcoolray
Addicted Member
From what I just checked on, your van is not old enough for restoration parts and not new enough for factory parts. But parts between C-body, pickups and vans interchange depending on the size of engine used and due to using the same alternator. That’s what’s great about auto wrecking yards, the comparison of parts...and serial numbers. Chrysler uses so many of the same parts over many generations.
Good luck...
knockbill
Lunatic Member
Yep,,, That's the problem... Junk yard is on the list, and using that quick resistance test in the link, it should be easy enough to find one that will work.... First I'll check with a couple of professional parts guys on Monday and see if I can get an adjustable VR... NAPA doesn't have it either...
knockbill
Lunatic Member
See post #7,,, 14.2VDC would be what were shooting for,, spec for this van is 13.9-14.6V... I talked to tech support for the new VRs I tried, they said manufacturers dropped some part numbers, and provide a replacement VR with a higher max allowable Voltage,,, 15.0V + or - is acceptable, as far as they are concerned!
damacman
Resident Psycho
15.0VDC won’t damage the accessories but it will dramatically shorten battery life. Case in pont my ex’s ‘12 Cruze charged at 14.8VDC every time I put a meter on it. That car goes through batteries every 24mos.
Incidentally, flooded lead acid batteries will last longer than AGM batteries with such high voltage. I agree with your plan - only I’d shoot for more like 13.8VDC output after the battery charge is replenished after a start.
Incidentally, flooded lead acid batteries will last longer than AGM batteries with such high voltage. I agree with your plan - only I’d shoot for more like 13.8VDC output after the battery charge is replenished after a start.
knockbill
Lunatic Member
Not sure I agree with the 15V being OK! The heater motor howls at 15V with the alt/reg in the ckt... runs fine on 12.5v battery only tho.... I pulled it yesterday to lube the bushings, and its quiet on 12-13V... this is just an old work van,, radio/heater are the only accessories, so there isn't a huge load on it...
the problem with trying to lower the charging rate with alternators and transistorized voltage regulators is that the regulator is instructed by the voltage it sees from the D+ terminal, (which is gathered from the "trio diodes" which are coming from the (3) apexes of the six big rectifying diodes.)
The voltage they produce is higher than the output voltage of the alternator. If you want to fool the regulator into reduced output, then this voltage needs to be higher than normal, not an easy manipulation.
However, if you desire higher output, a biasing network would (potentiometer with grounded leg) would probably work.
I do remember when I raced a Volvo, that using a Sev/Marchall regulator on a Bosch alternator resulted in a real nice (12.9v) output voltage.
Of course, if there's a difference in the ground plane voltages, (IE: regulator mounted to chassis, and a voltage drop between the alternator itself and the regulator, you'll get a higher charging voltage. You can try a jumper wire from the frame of the alternator to the ground connection (case?) of the regulator and see if the rate goes down.
If it does, go through the system looking for the lost voltage (voltage drops) with the meter: Alt to engine block; block to chassis; etc.
PS: manufacturers never expected to see charging voltage at consumers; they expect and accept the voltage drops that occur with larger consumers like headlights. It is quite a surprise to see what a full voltage at a headlight produces, like when you run a relay for high beams and #10 wire from battery to headlamp. The output of incandescent bulbs increases logarithmically by voltage because output is a function of watts and as voltage increases, so does current in the circuit, resulting in a second order at the output. Likewise, doesn't take much voltage loss to dim a lot.
The voltage they produce is higher than the output voltage of the alternator. If you want to fool the regulator into reduced output, then this voltage needs to be higher than normal, not an easy manipulation.
However, if you desire higher output, a biasing network would (potentiometer with grounded leg) would probably work.
I do remember when I raced a Volvo, that using a Sev/Marchall regulator on a Bosch alternator resulted in a real nice (12.9v) output voltage.
Of course, if there's a difference in the ground plane voltages, (IE: regulator mounted to chassis, and a voltage drop between the alternator itself and the regulator, you'll get a higher charging voltage. You can try a jumper wire from the frame of the alternator to the ground connection (case?) of the regulator and see if the rate goes down.
If it does, go through the system looking for the lost voltage (voltage drops) with the meter: Alt to engine block; block to chassis; etc.
PS: manufacturers never expected to see charging voltage at consumers; they expect and accept the voltage drops that occur with larger consumers like headlights. It is quite a surprise to see what a full voltage at a headlight produces, like when you run a relay for high beams and #10 wire from battery to headlamp. The output of incandescent bulbs increases logarithmically by voltage because output is a function of watts and as voltage increases, so does current in the circuit, resulting in a second order at the output. Likewise, doesn't take much voltage loss to dim a lot.
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Hmmm... appreciate the multiple grounds but did you actually measure for voltage drops. Weird things happen. Also measure what the regulator is seeing, make sure it is actual system voltage, and measure for voltage drop between regulator and positive battery terminal. It is assumed you are measuring charge voltage at battery terminals. 15 volts is within stated specs but in practice is too high if sustained. I've seen a number of them... many years of Mopar share this basic system, some regulate the feed to alternator field, others ground, but basically same system.... and they regulate at 14.2, a little less at idle depending on year and load but quickly come at or about 14.2 off idle. The first of those cheap electronic regulators I saw did not produce much confidence, don't weigh anything and cost ten dollars, but they have worked out just fine. It's been two or three years since I've worked on one of those charging systems and maybe something in the parts industry has changed.... those Chrysler/Dodge vans were good and many people kept them going, plus all the older Mopar cars.
knockbill
Lunatic Member
Battery V at B+ terminal of alt and Pos terminal of Battery is the same... of the three VRs I tried, all reading over 15V,,, none of them would pass the 1.75K resistance test in the link in post #15,,,, all read open between those two regulator terminals... I believe the parts guys are taking these things back on return, and passing them off to the next customer, along with the story that 15V is OK...
I can read a bit over 15volts (B+) off the new alt, which only a tenth or so volts over reading on battery terminals, so the regulators are not doing anything... Can't really make any more tests as I returned the two "new" VRs, and dissected the original one, finding a missing/burned off middle terminal on the big chip (see pic post #22)...
Finding a working, (must pass the R test before I walk out with it!) VR seems to be the challenge here...
Also. seems there are 60A and 78A rebuilt alts available as direct replacements for this van,,, I have a supposedly 78A rebuilt replacement installed now, not sure what the old one was... there seems to be only one VR around now tho,,, everyone I spoke to carries the generic one, just different price point...
I can recheck ground connections, and voltage drop on the battery and alt wires... but after I found and repaired the broken weld between the alt B+ cable and fuseable link, voltage readings were good to any ground point...
Sad part of this story is, I could have probably just repaired the B+ wire while there were a couple strands still attached, had I realized it,,, and kept driving with the old parts.... But the alt bearings were going also, so I replaced it, and most likely severed the B+ wire completely, while removing/connecting the new alt so here we are!!!!!
Thanks to everyone that contributed so far,,, I'm sure we'll get it,, just have to find reliable parts, which may be the real challenge here.. its a 318 Dodge,,, can't be a more bullet proof, commercial engine ever made!!!
I can read a bit over 15volts (B+) off the new alt, which only a tenth or so volts over reading on battery terminals, so the regulators are not doing anything... Can't really make any more tests as I returned the two "new" VRs, and dissected the original one, finding a missing/burned off middle terminal on the big chip (see pic post #22)...
Finding a working, (must pass the R test before I walk out with it!) VR seems to be the challenge here...
Also. seems there are 60A and 78A rebuilt alts available as direct replacements for this van,,, I have a supposedly 78A rebuilt replacement installed now, not sure what the old one was... there seems to be only one VR around now tho,,, everyone I spoke to carries the generic one, just different price point...
I can recheck ground connections, and voltage drop on the battery and alt wires... but after I found and repaired the broken weld between the alt B+ cable and fuseable link, voltage readings were good to any ground point...
Sad part of this story is, I could have probably just repaired the B+ wire while there were a couple strands still attached, had I realized it,,, and kept driving with the old parts.... But the alt bearings were going also, so I replaced it, and most likely severed the B+ wire completely, while removing/connecting the new alt so here we are!!!!!
Thanks to everyone that contributed so far,,, I'm sure we'll get it,, just have to find reliable parts, which may be the real challenge here.. its a 318 Dodge,,, can't be a more bullet proof, commercial engine ever made!!!
knockbill
Lunatic Member
Thanks for the offer... there are junkyards in the area,,, not sure what is left on cars/trucks of this vintage tho,,, I'll bring a DMM if it comes to that,, but the cars in the yards most likely have had VRs replaced also, however its probably not the crap that's on the market today!!
petehall347
the brandy coffee man
i used to see adjustable regulators on commercial vehicles .. setting were low medium high .. it was set for whatever the vehicles job was . like round town it would be set to high .. long distance set to low .
could you not simply fit an alternator with built in regulator ?
depending on how the battery warning light is wired in simply changing the bulb for higher wattage will reduce alternator output . worth a try i think .
could you not simply fit an alternator with built in regulator ?
depending on how the battery warning light is wired in simply changing the bulb for higher wattage will reduce alternator output . worth a try i think .
knockbill
Lunatic Member
That's what it would look like,,, but new at 20 bux scares me,,, the non adjustable, bad ones I got cost that much!!!