Solid-state Replacement for Mech. Voltage regulator (1 Viewer)

[PabloCruise]

O-k, so things are not as groovy as I initially thought with my charging system...

Problem: after sitting for ~ 1 week, the battery was damn near dead.

Background: '78 40 w/ stock charging system. I gave the 40 a nice long drive before leaving it sit while my son was born (see Chat). Before I went w/ the SS VR, my battery was draining overnight. I surmised that the VR was fielding the alternator overnight and doing this. So I got a points type VR, and then a week later switched to the SS VR.

One thing that concerns me is that after I got the 40 started, the Amp meter was not pegged, or showing vigorous charging activity... When I hooked it up to a trickle charger, it drew 8 and then 6 amps for the better part of a day. Battery now acts fully charged.

In my feeble little mind, this means to me that either the VR is not calling for a charge, or my alternator is no longer putting out - correct?

Would step one be to fully field the alternator and measure output? If so, how do I fully field my stocker 40, external VR alternator?

Back to this question...

 

[Pin_Head]

If you look at the '78 schematic in tech links, you will notice that the VR and most of the rest of the truck has no power unless the key is in the run position, so it can't be be the source of the drain (unless the key is shorted).


Only the brake lights, headlights, tail lights and cigarette lighter fuses are "hot" with the key off. If you remove these fuses one at a time while measuring the current drain (amps) at the battery you can tell if one of the circuits has a short.

If none of these circuits has a short, then the drain is likely upstream of the fuse block, which doesn't leave too many possibilities: the alternator, starter, ignition switch, fuse block and the wiring between these places. Disconnect the white / blue stripe wire at the alternator and see if the drain disappears. If so you have a bad diode that is ("punched through") or conductive in both directions.

You can "full field" the alternator for test purposes by jumpint between the B lug and the F terminal of the alternator with a wire or paper clip.

 

[bsevans]

If you look at the '78 schematic in tech links, you will notice that the VR and most of the rest of the truck has no power unless the key is in the run position, so it can't be be the source of the drain (unless the key is shorted).


Only the brake lights, headlights, tail lights and cigarette lighter fuses are "hot" with the key off. If you remove these fuses one at a time while measuring the current drain (amps) at the battery you can tell if one of the circuits has a short.

If none of these circuits has a short, then the drain is likely upstream of the fuse block, which doesn't leave too many possibilities: the alternator, starter, ignition switch, fuse block and the wiring between these places. Disconnect the white / blue stripe wire at the alternator and see if the drain disappears. If so you have a bad diode that is ("punched through") or conductive in both directions.

You can "full field" the alternator for test purposes by jumpint between the B lug and the F terminal of the alternator with a wire or paper clip.

I ran into an issue with my brakelights occasionally staying on. It turns out that they put grease on the tip of the switch and over the years it migrated into the switch and dried out causing the switch to not fully return and disconnect power to the brakelights on occasion. I found this out when I saw that the brake light lens had deformed from the brake light being on too long.

 

[PabloCruise]

Only the brake lights, headlights, tail lights and cigarette lighter fuses are "hot" with the key off. If you remove these fuses one at a time while measuring the current drain (amps) at the battery you can tell if one of the circuits has a short.

If none of these circuits has a short, then the drain is likely upstream of the fuse block, which doesn't leave too many possibilities: the alternator, starter, ignition switch, fuse block and the wiring between these places. Disconnect the white / blue stripe wire at the alternator and see if the drain disappears. If so you have a bad diode that is ("punched through") or conductive in both directions.

You can "full field" the alternator for test purposes by jumpint between the B lug and the F terminal of the alternator with a wire or paper clip.

Wonderful - this makes sense.

The battery has not drained on me since I reported initial problem

We had several days of weather near 0 degrees and I thought for sure the Cruiser would be dead. It was not. Seems to be charging fine ever since I put a trickle charger on it.

Tested alternator output today. Under load test and fully fielded, she put out just fine: >30A.

I'll check the diode array another day.

 

[PabloCruise]

Would a faulty diode array allow the alternator to charge sometimes and not others? Or could it be responsible for diminished output from stock alternator?

 

[PabloCruise]

On further testing it looks like the alt was fine, the new SS VR was not fielding the alternator.

Bummer.

I'm thinking I'll throw my points type VR back in for now...

 

[IDave]

I'm thinking I'll throw my points type VR back in for now...

My new points VR works great!

 

[DSRTRDR]

So my question is, why would you not buy one that is plug compatible with a cruiser as opposed to buying one meant for another vehicle and change out the connectors with questionable results?

my VR now is already an aftermarket VW/Bosch and I have yet to figure out how I would connect the individual wires of the plug if I had to swap in a new one - fortunately no need yet

 

[DSRTRDR]

What's in my 2/71 currently. There is no plug, the wires with ring terminals go under screws on this regulator...

ditto here

 

[Pin_Head]

my VR now is already an aftermarket VW/Bosch and I have yet to figure out how I would connect the individual wires of the plug if I had to swap in a new one - fortunately no need yet

You could try guessing and have a 50% chance of being correct, because there are only two wires (not counting the ground). Usually they are marked "Ign" which goes to the key on hot wire and F which goes to the field (F) terminal of the alternator. One way it would work and the other way it wouldn't.

 

[Pin_Head]

Would a faulty diode array allow the alternator to charge sometimes and not others?

No.

Or could it be responsible for diminished output from stock alternator?

Yes. More typically they also allow the battery to drain through the stator because when they go out, they conduct in both directions.

It is EZ to check them: disconnect the white/blue stripe wire at the B lug of the alternator. Measure the resistance between the B lug and the case. Reverse the leads and measure again. In one direction the resistance should be very low and in the other it should be very high.

 

[tabascoloco]

Great information

I'd like to thank eveyone for there input on this conversion...I'd like to know how the IN568 bolted up for you guys...

I read the link posted above about the NAPA VR128 and that the holes were within 1/16 inch of factory...that's nice.


Thanks everyone...hope this remedies the way my lights dim and go bright, etc...up and down...etc...I've not had any electrical issues other than than...never had any shorts/drain or anything other than the erratic output. Have tried new battery, clean all grounds, etc....still seems weak/erratic when cold especially...

 

[ChrisK]

Reviving this old thread ... trying to find a SS replacement for my 7/69's 27700-40010 VR. The URL that some folks found useful is now 404 ... can someone help? My truck doesn't have a molded connector, just screw terminals.

Thanks!

 

[bsevans]

Reviving this old thread ... trying to find a SS replacement for my 7/69's 27700-40010 VR. The URL that some folks found useful is now 404 ... can someone help? My truck doesn't have a molded connector, just screw terminals.

Thanks!

The URL and instructions in post 24 still function properly and will let you look at the VR they carry. I'm not sure they make a SS VR replacement for your year FJ40. If you follow the instructions in post 24 you can look at the photos of all the VRs they make.

 

[alkarich]

Glad this thread was revived. I'm going to look into doing this mod. Thanks for all the info.

 

[spotcruiser]

This gives me an idea. I see no reason why a guy couldn't mount a Delco regulator in the LC regulator enclosure and wire it up. I have a spare Delco regulator and an old LC regulator, so maybe I'll give it a try.

 

[ChrisK]

The URL and instructions in post 24 still function properly and will let you look at the VR they carry. I'm not sure they make a SS VR replacement for your year FJ40. If you follow the instructions in post 24 you can look at the photos of all the VRs they make.

Right. If you look at post 25, you'll see that Coolerman already discovered that they don't.

It's post 27 that looked promising and is now 404...

 

[Coolerman]

I have not found a direct source for the early SS VR but keep this in mind if you are looking:

A regulator does nothing more than control the amount of field (rotor) current in the alternator. This 'regulation' causes the alternator output voltage to remain at a pre-set 14 volts or so.

Alternator output current is NOT regulated by the regulator. Alternator output current is more related to RPM, the internal resistance of the battery, and it's state of charge, but mostly by the load on the electrical system.

What this means is ANY 3 terminal (+12V, GND, Field) regulator will work with an early 40-50 amp alternator, IF it has the ability to handle the field current, and is set, or can be set, to about 13.8 to 14.6 volts regulation. It's just a matter of finding one and making the connectors work. A good auto electrical shop should be able to provide the specs of the regulator making it easy to choose one that will work.

When I get to this point in my build I will research this and post what I find.

 

[lostmarbles]

Tremendous thread - So I thought I'd add a "down-under" aspect to it.

Plug-in-replacement solid-state regulators are available in this part of the world too and are distributed by a mysterious Australian Company called OEX accessories. (Mysterious to me because there is no access to their catagues on-line that I can find - yet they even supply remanufactured starters which could be of interests to those of us with old cruisers.)

Anyway here is the solid state voltage regulator I've just bought from them for my 1979 BJ40 through REPCO here in NZ. (REPCO I guess is abit like NAPA in the States.) Cost me $86NZ but we're used to "paying through the nose" in this part of the world. (The cost of living in paradise )

Here are some pics:

 

[lostmarbles]

Here is the way I think my 1979 BJ40 is wired (as far as the charging system goes):



But I'm not 100% sure that the internal wiring of the regulator is correct as I've drawn it. Toyota seem to vary this according to which diagram you look at - and some clearly contain drawing-errors. (It would help if I knew exactly how the regulator does its job.)

Anyway - so that RGX2032 regulator is the down-under equivalent to the Transpo IN551 regulator.