Jump to content
desoto1939

converting to 6v pos grd alternator 1 wire

Recommended Posts

I have been thinking about converting my stock 39 Desoto over to a 6v positive grnd alternator 1 wire system.

 

What do I have to change and how is the 1 wire run to the apprppriate point on the cr.  My car has the foot pedal start and the starter selinoid sits on top of the starter and this is where the negative battery cable is attached tot he starter.

 

I currently have a headlight relay installed and have a 10gage wire running from the selinoid and battery cable connection to power the 6v headlight relay.

 

Still have the original 6v regulator on the firewall.

 

So what do I disconnect from the gen? I know there are two wires F and A that run to the voltage reg and then the one wire runs to the amp gage.

 

So do I disconnect both wires that run to the volt reg and were do I run the single wire from the alternator.

 

I can purchase the 60 amp or around a 35 amp alternator.

 

I stillhave the old bulb system headlights and was thinking of converting also to halohen style bulbs, not sealed beams beaches my car in 39 was the last year to use bulbs before converting over to sealed beams.  want to retain the look of the old style headlights to keep it more original looking and to also provide me with better night time driving capabilities.

 

I have extra headlight reflectors that can be modified to accept the halogen light and drillthe reflector for the mounting hardware.  Would run new 14 gage wires to the terminal blok. Also the car was rewired with modern wire and all wiring was upgraded to at least 14 gage wireing.

 

Any input is greatly appreciated.

 

Rich HArtung

desoto1939@aol.com

 

 

Share this post


Link to post
Share on other sites

I will be doing this shortly to my '37 as well. The wire from the alternator goes to the 'BAT' battery wire on the regulator. ie., the one going to the ammeter. 

 

 It shouldn't have any affect on the other systems.

 

The F & A wires on the generator and regulator should be terminated off. 

Edited by maok

Share this post


Link to post
Share on other sites
1 hour ago, desoto1939 said:

I have been thinking about converting my stock 39 Desoto over to a 6v positive grnd alternator 1 wire system.

 

What do I have to change and how is the 1 wire run to the apprppriate point on the cr.  My car has the foot pedal start and the starter selinoid sits on top of the starter and this is where the negative battery cable is attached tot he starter.

 

I currently have a headlight relay installed and have a 10gage wire running from the selinoid and battery cable connection to power the 6v headlight relay.

 

Still have the original 6v regulator on the firewall.

 

So what do I disconnect from the gen? I know there are two wires F and A that run to the voltage reg and then the one wire runs to the amp gage.

 

So do I disconnect both wires that run to the volt reg and were do I run the single wire from the alternator.

 

I can purchase the 60 amp or around a 35 amp alternator.

 

I stillhave the old bulb system headlights and was thinking of converting also to halohen style bulbs, not sealed beams beaches my car in 39 was the last year to use bulbs before converting over to sealed beams.  want to retain the look of the old style headlights to keep it more original looking and to also provide me with better night time driving capabilities.

 

I have extra headlight reflectors that can be modified to accept the halogen light and drillthe reflector for the mounting hardware.  Would run new 14 gage wires to the terminal blok. Also the car was rewired with modern wire and all wiring was upgraded to at least 14 gage wireing.

 

Any input is greatly appreciated.

 

Rich HArtung

desoto1939@aol.com

 

 

 

Rich,

 

Here is a wiring diagram on the website for the vendor that supplied my 6v alternator:

 

GentoAltWiringDiagram.jpg

 

This diagram is for a negative ground system, just reverse the battery connections in the diagram if you have a positive ground. I added a large fuse in the lead coming from the alternator in case that lead or the alternator ever failed to ground:

 

alternator.jpg.554c025afa3266103eda658aa76f1cd6.jpg

 

The alternator is a fantastic upgrade, gets rid of the ancient stuff and provides more capacity than the generator ever dreamed about.  You will never have to worry about your battery not being fully charged.     :)

Edited by Sam Buchanan

Share this post


Link to post
Share on other sites

Careful there, if you are putting a positive output negative case alternator in, like shown in the drawing, and you swap the battery connections you are likely to let the smoke out of something.

Share this post


Link to post
Share on other sites

I am going to be putting in a ^V Positive Ground Alternator since the 39 Desoto is stil positive grounded.  I know to order a positive ground unit.

 

Rich

Share this post


Link to post
Share on other sites
3 minutes ago, Sniper said:

Careful there, if you are putting a positive output negative case alternator in, like shown in the drawing, and you swap the battery connections you are likely to let the smoke out of something.

 

Go back and carefully read the notes and diagram.....

Share this post


Link to post
Share on other sites

U rread the notes, I see the diagram.  It shous a negative case, positive output alternator in a negative grouns syste,

 

In that specific circumstance ig you just

Share this post


Link to post
Share on other sites

I read the notes, I see the diagram.  The diagram shows a negative case, positive output alternator in a positive ground system.

 

In that specific circumstance if you just " reverse the battery connections" you will smoke something.  The drawing is a poor one for a positive ground setup and is likely to lead to confusion when someone with minimal electrical experience tries to use it.   

Edited by Sniper

Share this post


Link to post
Share on other sites

I understand the battery terminal issue. But on my 39 Desoto the Battery is under the front seat under the driver So the positive grounded cable is going to the frame also with a strap flat cable to help with the grounding.

 

The negative cable runs up to the starter selinoid and or starter switch that is on top of the starter. My car has the foot pedal driven starter mechanism.  So from reading the information and the Alternator would be a positive grounded unit the 1 wire from the alternator would still then run up to the Battery side of the original volt regulato.  I woud disconnect the F A wires from the volr regulator and they would also be disconnected from the generator since this would be replaced with the positive grounded Alt.

 

The 1 wire leading to the Battery Terminal on the Old Volt reg would attach at this point and there would also be a wire running to the 6v original Amp meter in the dash.

 

I have a 10 gage wire running from the starter selinoid to the 6v headlight relay.  So I would then have the 00 sized negative battery cable, 10 Gage wire that runs to the headlight relay and a new wire 10 gage that would run from the Battery terminal on the volt reg do to the connection where the battery cable attaches to the starter selioid 

Since the Alt is a positive grunded unit I would assume that the wire running from the Alt to the battery connection on the volt reg and then running to the connection on the top of the starter should be correct because the alt would be a positive grouded unit and the supply of the electrical connection would be feeding back throught the 1 wire via the connection on the volt reg and the connection from there to the starter and negative post on the starter selioid.  Correct or not correct.

 

rich hartung

desoto1939@aol.com

Edited by desoto1939

Share this post


Link to post
Share on other sites

Maybe the VR does it in this schematic but don't you need a pilot light (idiot light) to keep from back feeding with IGN off?  I had to wire my three wire gm in my Studebaker but maybe with the one wire it's not needed.

Share this post


Link to post
Share on other sites
40 minutes ago, desoto1939 said:

 

 

The negative cable runs up to the starter selinoid and or starter switch that is on top of the starter. My car has the foot pedal driven starter mechanism.  So from reading the information and the Alternator would be a positive grounded unit the 1 wire from the alternator would still then run up to the Battery side of the original volt regulato.  I woud disconnect the F A wires from the volr regulator and they would also be disconnected from the generator since this would be replaced with the positive grounded Alt.

 

The 1 wire leading to the Battery Terminal on the Old Volt reg would attach at this point and there would also be a wire running to the 6v original Amp meter in the dash.

 

 

 

Correct. Wire from the alternator connects to the wire going to the ammeter, and the generator F and A wires are retired. That's all there is to it.  :)

Share this post


Link to post
Share on other sites
4 minutes ago, greg g said:

Maybe the VR does it in this schematic but don't you need a pilot light (idiot light) to keep from back feeding with IGN off?  I had to wire my three wire gm in my Studebaker but maybe with the one wire it's not needed.

 

No light needed, this is a one wire system.  And it works beautifully.   :)

Edited by Sam Buchanan

Share this post


Link to post
Share on other sites

For those who have used a 1 wire alternator with an output greater than your factory amp meter, does the system peg the amp meter upon startup? Especially after sitting a while when the battery may be low.

I put a power master one wire (basically the same as a one wire alternator) on my car but was worried about the amp meter at 60-65 amp output so I used a shunt (just a 14ga wire about 2 ft long) straight  to the battery so some of the current bypassed the amp meter. The only problem is to much current bypasses the meter and the meter is basically of no use. I have a volt gauge so not really needed but was curious and wanted the op to also be aware the output of a one wire alternator would exceed the amp meter capacity and if that is a concern. 

Share this post


Link to post
Share on other sites

One side bar-

 

My 47 DeSoto was wired to ground the starter solenoid through the field of the generator.  That way, when the engine was running, the back current in the generator would not provide a suitable ground for engaging the starter, thus keeping the dummy behind the wheel from trying to engage the starter when the engine was running.  

 

When I installed my alternator, I grounded the wire that ran from the starter solenoid to the generator.   Fine, except that it no longer protected the starter from operator error. 

 

This may not be a big problem, but one solution is to install an oil pressure switch, with a normally-on contact that turns off when the engine is running.  (l installed such a switch to keep the electric fuel pump from running on if the engine stalls.  I push a separate momentary contact switch to run the electric pump for priming the caerburetor.)  

Share this post


Link to post
Share on other sites
6 hours ago, Bbdakota said:

For those who have used a 1 wire alternator with an output greater than your factory amp meter, does the system peg the amp meter upon startup? Especially after sitting a while when the battery may be low.

I put a power master one wire (basically the same as a one wire alternator) on my car but was worried about the amp meter at 60-65 amp output so I used a shunt (just a 14ga wire about 2 ft long) straight  to the battery so some of the current bypassed the amp meter. The only problem is to much current bypasses the meter and the meter is basically of no use. I have a volt gauge so not really needed but was curious and wanted the op to also be aware the output of a one wire alternator would exceed the amp meter capacity and if that is a concern. 

 

Since the alternator keeps the battery fully charged when the car is in use and I've never seen the alternator charge a really dead battery, I don't know the answer to your question. The most I've ever seen after the car sits for a week or so is about 1/3 scale deflection for a few seconds then the needle eases back to near zero in a minute or so as the car idles. If the battery has been idle for a long time putting a charger on it prior to startup would address this concern and also keep the alternator from working as hard.

Share this post


Link to post
Share on other sites

on my 39 desoto I have a 3amp charger always hooked to the battery to keep it fully charged and this also prolongs the life of the battery so there should not be an issue with the battery being low on charge.

 

Rich Hartung

Share this post


Link to post
Share on other sites

Rich,

I have one of these single wire 6v positive ground alternators on my truck. The unit I have is from Quality Power. It has been flawless. 

You can either use the terminal on the old regulator or run it straight to the battery terminal on the pedal starter. I did it the later way. 

I run with a pair of 6 volt Optima red tops. I have never needed a remote charger. This alternator eliminates any charging issues.

Batteries are always ready to go.

Jeff

Share this post


Link to post
Share on other sites

This may or may not help...

I purchased and installed a 6 volt positive ground alternator from Quality Power this weekend.

The size of the bottom mounting tabe on the alternator required a adjustable bracket.

https://images.app.goo.gl/YRXZG7WNhV64sPxg8

The original top bracket didn't work either, so I used a bracket from Mr Gasket.

https://shop.advanceautoparts.com/p/mr-gasket-universal-alternator-generator-arm-9851/6121551-p?c3ch=PLA&c3nid=6121551-P&adtype=pla&product_channel=online&store_code=&gclid=EAIaIQobChMIyquz3omR5wIV5JJbCh3-igoqEAQYASABEgKo0_D_BwE&gclsrc=aw.ds

I had to cut and drill a hole to mount.

I had to remove fan blade bolts to make enough space behind water pump pulley to remove the bolt which holds the top bracket.

The bolt sits inside the water jacket, so there will be a loss of coolant.

The wiring is the easiest part. Removed the original wires from generator to regulator. Ran a single wire from alternator to the battery terminal on the regulator.

I ran out of day light before I could properly test. 

IMG_20200118_152330-2268x3024.jpg

Share this post


Link to post
Share on other sites
4 hours ago, Jeff Balazs said:

Rich,

I have one of these single wire 6v positive ground alternators on my truck. The unit I have is from Quality Power. It has been flawless. 

You can either use the terminal on the old regulator or run it straight to the battery terminal on the pedal starter. I did it the later way. 

I run with a pair of 6 volt Optima red tops. I have never needed a remote charger. This alternator eliminates any charging issues.

Batteries are always ready to go.

Jeff

Jeff:  The reason I keep the 3 amp battery charger hooked up to the car is to prolong the life of the battery.  I attend the AACA annual meeting in Philadelphia each year.  There is an egineer that comes down from Penn State University and he has had many lectures on battery life.  He has tested 6 v batteires and shows that by keeping a 3amp trickle charge on our 6v batteries is stops the flaking away from the ploates in the battery and this then helps to extend the longevity of the battery.  The slow flaking off of the metal plates is wht causes the battery to lose it charge over time.  He has shown that by using the tender unit you can get 8-10 years out of a regular 6v lead battery.  I have been doing this and have gotten at least 8 years out of my batteries. I live near valley forge so we do get cold weather and snow.

 

Also thanks for the input. Did you put on a 60 amp alt or a smaller unit?

Share this post


Link to post
Share on other sites
12 hours ago, tom'sB2B said:

 

I had to remove fan blade bolts to make enough space behind water pump pulley to remove the bolt which holds the top bracket.

The bolt sits inside the water jacket, so there will be a loss of coolant.

 

 

When I replaced the water pump on the P15 I got ahead of myself and installed the pulley and fan before realizing I had not previously installed the generator bracket. Instead of removing the fan and pulley so the water pump bolt could be removed I "slotted" the hole in the bracket so the bolt would only need to be loosened a few turns and the bracket slid into place under the head of the bolt. This doesn't compromise the bracket since it is held in place in compression by tension on the fan belt. The bolt tightened back up with no water leakage.

Edited by Sam Buchanan

Share this post


Link to post
Share on other sites

on the early mopars around the mid 30's to mid 40's the water pumps and on my 39 Desoto the wp is held onto the front of the block by three studs and three bolts.  So all I have to do is just loosen the upper bolt and the genearator braket can pivot.

 

There isa problem that does occur when you get a newer WP.  The issue is that on the lower left portion of the newer redesigned WP that have the sealed bearing they made the body of the WP thicker. Originally this area was only approx. 1/2 thick and therefore the original stud would come through the hole and then you could use the bolt to hold the unit onto the block. But since this is now thicker approx. 1 inch they supply a bolt that woud go into the block.  So with the older cars you would have to remove the old stud that has been in the block for who know how long and with the heat and all of the other years there isa good possibility of breaking the stud in the front of the engine block.

 

So if you have the early style water pump make sure that when you get a rebuilt pump that it has the thin body in the lower left area where the return hose attaches to the body of the wp.  I found this out the hard way just before going to the National Desoto convention in Maryland a few years back.

 

So if you have the older style WP keep thee as spares. I was talking to Art Gould's son at Hershey this past October and he stated that if there is enough metal he can drill out the old bronze bushing area and install the sealed bearing.  It all depends on if there is enough metal left in the main body of the WP.  The sealed bearing is much better than the old fiber bushing ad you do not habe to worry about greasing the WP and or over greasing the bushing and then the WP starts to leak were the main bearing connects to the wp hub.

 

Rich Hartung

desoto1939@aol.com

Share this post


Link to post
Share on other sites
13 hours ago, desoto1939 said:

Jeff:  The reason I keep the 3 amp battery charger hooked up to the car is to prolong the life of the battery.  I attend the AACA annual meeting in Philadelphia each year.  There is an egineer that comes down from Penn State University and he has had many lectures on battery life.  He has tested 6 v batteires and shows that by keeping a 3amp trickle charge on our 6v batteries is stops the flaking away from the ploates in the battery and this then helps to extend the longevity of the battery.  The slow flaking off of the metal plates is wht causes the battery to lose it charge over time.  He has shown that by using the tender unit you can get 8-10 years out of a regular 6v lead battery.  I have been doing this and have gotten at least 8 years out of my batteries. I live near valley forge so we do get cold weather and snow.

 

Also thanks for the input. Did you put on a 60 amp alt or a smaller unit?

I installed the 50A unit. It easily handles things including a fairly powerful stereo....extra lighting...etc. I cant imagine needing more than that.

Jeff

Share this post


Link to post
Share on other sites

Hi Rich,

 

After you install the new Alternator, can you please send in some pictures?

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Terms of Use