What's wrong with 6 volts?

[Sparkydave]

Trying to figure out something.  A number of folks have already been asking me if I'm going to switch the Lincoln over to a 12 volt negative ground system.  I say no, it's been working fine for 77 years with a 6 volt positive ground system.  They look at me like I'm nuts and there is some perceived need to change it.  I'm an electrical engineer, so I understand the technical reasons why 12 volt systems made 6 volts obsolete (lower current for the same amount of power, so no need for heavy gauge wires), but I also know that changing it over to 12 volt would be difficult since the radio, power window pump, gauges, starter, generator, overdrive solenoids, and all the lights would have to be changed to 12 volt.  I see no reason to change it.  I just have to remember to flip the switch to 6 volts on my battery charger, and that the red and black cables from the charger have to be reversed since the red lead is negative.

[The 55er]

There's nothing wrong with 6 volts. If it ain't broke don't fix it. 

[Matt Harwood]

I've found that the people who recommend 12 volts aren't particularly good mechanics. Instead of actually fixing things, they prefer to just go to the auto parts store and buy another one. Your attitude towards the change is the right one.

[Dodgeman]

Some people want to be able to charge their phones or run modern electronics in their vintage car and changing to 12 volts accomplishes that. However there are ways to do that with a 6 volt system. You just need to do your research. Also the slow cranking speed is unfamiliar to people. I’m fine with 6 volts in my Coronet.

[rocketraider]

As an EE you have a better understanding of your Lincoln's electrical system than your 12v proponent associates do. 

 

The only things wrong with 6 volts are its perception as "inadequate" by people who don't understand electricity, and it doesn't fit the narrative that all old cars have to be modified or "upgraded" before they can possibly be driven and used. These are the same people who think 20 foot long 8 gage jumper cables are fine.

 

Well... finding 6v light bulbs might be a problem!😄

 

With suitably sized cabling and clean connections 6v works fine. Kudos for keeping your Lincoln as the Ford engineers designed it.

[West Peterson]

It's a whole lot easier to fix something wrong with a six-volt system than to change it to 12-volt, so I don't understand the want/need to change, either.

[Sparkydave]

24 minutes ago, rocketraider said:

With suitably sized cabling and clean connections 6v works fine. Kudos for keeping your Lincoln as the Ford engineers designed it.

Totally agreed on CLEAN connections.  Over the years it had been getting a little dicey starting it when the engine was hot, so dad resorted to finding the highest CCA batteries he could find, usually tractor batteries.  Still had to push start it occasionally though.  When he gave it to me earlier this year and I started getting it running again, it was cranking even slower than I remembered it.  My calibrated finger told me there was something seriously wrong with the starter and solenoid connections as they were hot after just a few seconds of cranking.  Polished them up, and it made a world of difference.  The ancient starter solenoid's terminals were still getting pretty toasty though, and with a new starter solenoid they are staying cool and the engine is cranking way better.

[alsancle]

1 hour ago, Sparkydave said:

Trying to figure out something.  A number of folks have already been asking me if I'm going to switch the Lincoln over to a 12 volt negative ground system.  I say no, it's been working fine for 77 years with a 6 volt positive ground system.  They look at me like I'm nuts and there is some perceived need to change it.  I'm an electrical engineer, so I understand the technical reasons why 12 volt systems made 6 volts obsolete (lower current for the same amount of power, so no need for heavy gauge wires), but I also know that changing it over to 12 volt would be difficult since the radio, power window pump, gauges, starter, generator, overdrive solenoids, and all the lights would have to be changed to 12 volt.  I see no reason to change it.  I just have to remember to flip the switch to 6 volts on my battery charger, and that the red and black cables from the charger have to be reversed since the red lead is negative.

Lose the phone number of anybody that tells you to convert to 12 volts.

 

Also, clean the ground connection and make sure the cables are OO.

[Larry Schramm]

9 minutes ago, alsancle said:

Lose the phone number of anybody that tells you to convert to 12 volts.

 

Also, get some new battery cables. Preferable welding cables 00 or 000 size.  Put new terminals on both ends and SOLDER the new terminals to the cables and you will be amazed at how well the car will then start.  If not a world of difference, then and only then check the starter/solenoid.  FYI, Soldering fixed lots of errors in cable crimps.

[alsancle]

34 minutes ago, Larry Schramm said:

 

Also, get some new battery cables. Preferable welding cables 00 or 000 size.  Put new terminals on both ends and SOLDER the new terminals to the cables and you will be amazed at how well the car will then start.  If not a world of difference, then and only then check the starter/solenoid.  FYI, Soldering fixed lots of errors in cable crimps.

This!

[Rusty_OToole]

We get queries all the time from people wanting to change 6V cars to 12V, add power steering, replace the complete front suspension, replace the engine with an OHV V8 and other "upgrades". Invariably they are amateurs who have no idea what they are talking about, probably influenced by some equally ignorant friend. Also invariably, it would be better easier and cheaper to fix the car properly than gut it like a trout.

[joe_padavano]

As a very hands-on motorhead who is also an aerospace engineer, I'll give you the pragmatic answer. Yes, obviously the 6V system worked fine when it was new. The problem is that every connection is a potential voltage drop now that they are all dirty and corroded, and the higher current in the 6V system will cause more heating and pitting at those resistive connections, which is a self-perpetuating problem. Sure, you can take the time to completely disassemble the wiring harness and carefully clean every contact and splice. The reality is that a 0.9v drop on a 6V system is a much bigger deal at the starter and headlights than a 0.9V drop in a 12V system. And frankly, people have been converting 6V systems to 12V for over half a century now. It's not rocket science (and yes, I am qualified to say that). I'll defer on the oddball issues like the Chrysler transmissions and the OD trans solenoids, but for the basic stuff, this is not the big deal that everyone makes it out to be. Sorry, but that has not been my experience.

[hook]

Some people just don't understand electricity, nor do they know how to read a simple schematic or wiring diagram.

[West Peterson]

16 minutes ago, joe_padavano said:

As a very hands-on motorhead who is also an aerospace engineer, I'll give you the pragmatic answer. Yes, obviously the 6V system worked fine when it was new. The problem is that every connection is a potential voltage drop now that they are all dirty and corroded, and the higher current in the 6V system will cause more heating and pitting at those resistive connections, which is a self-perpetuating problem. Sure, you can take the time to completely disassemble the wiring harness and carefully clean every contact and splice. The reality is that a 0.9v drop on a 6V system is a much bigger deal at the starter and headlights than a 0.9V drop in a 12V system. And frankly, people have been converting 6V systems to 12V for over half a century now. It's not rocket science (and yes, I am qualified to say that). I'll defer on the oddball issues like the Chrysler transmissions and the OD trans solenoids, but for the basic stuff, this is not the big deal that everyone makes it out to be. Sorry, but that has not been my experience.

But it's a bigger deal than to just take a little time in cleaning the terminals mentioned. 

[hook]

Do you want an old car or don't you? While you're at it changing to a 12 volt system why don't you install disc brakes and duel master cylinder, plus air conditioning, power steering, air bags, blue tooth and satellite radio. Oh, don't forget new rims, tubeless tires and anti-lock brakes.

[joe_padavano]

20 minutes ago, West Peterson said:

But it's a bigger deal than to just take a little time in cleaning the terminals mentioned. 

I'll challenge that. Accessing all the terminals and splices is not trivial, especially for the ones under the dash. And when the corrosion is between the terminal and the wire (inside the crimp), well, that's a slippery slope to a new harness. 😉

[ABear]

1 hour ago, Larry Schramm said:

Put new terminals on both ends and SOLDER the new terminals to the cables and you will be amazed at how well the car will then start.  If not a world of difference, then and only then check the starter/solenoid.  FYI, Soldering fixed lots of errors in cable crimps.

I would have to agree with soldering, provided you have good new clean wire and terminals to work with. Attempting to rework with solder on old corroded wire can be an exercise in frustration and failure, must be nice clean wire and do not use flux not rated for wire as different types of flux used in automotive work will contain considerable amount of acid that is not rendered harmless with heat and will eat the copper up..

 

Although one must be careful using the solder word on some forums in a mobile environment with vibration, using that word can get you banned from some forums as they believe that soldering is inferior to crimps.. I have had to find and fix a lot of bad crimps over the yrs in robotic systems with good old solder..

[Dr B]

55 minutes ago, hook said:

Do you want an old car or don't you? While you're at it changing to a 12 volt system why don't you install disc brakes and duel master cylinder, plus air conditioning, power steering, air bags, blue tooth and satellite radio. Oh, don't forget new rims, tubeless tires and anti-lock brakes.

Welcome to the resto-mod scene! 😱

 

Robert

Edited September 23 by Dr B (see edit history)

[ia-k]

The one benefit I could see of having a 12V system on an old car is if the battery is dead and you need a jump start. Slim pickings for a jump unless you are with a group of other old cars and one of them is 6V.

 

Is there jump packs that have both 6V and 12V settings like some battery chargers?

 

My 6V car is a manual transmission so I could always get it rolling and "pop the clutch".

[DavidinCA]

I’ve always been a fan of keeping things original, since these cars were, for the most part, used as daily transportation and presumably worked more often than not.  One of the first things I learned on these forums was the importance of proper battery cables with clean, paint free connections on a 6v system.  When I went and made that very straightforward change it made a world of difference and was quite inexpensive as well.  

 

For me, the biggest issues with 6V is that incandescent headlights in general are not nearly as bright as modern LEDs even after making sure the connections are clean.  Living in a somewhat rural area with lots of deer makes driving at night less than ideal, and more light would definitely be better.  It hasn’t bothered me enough to look for 6V LED headlights, so it may be easier to solve than I think.  

 

 

[ABear]

21 minutes ago, ia-k said:

Is there jump packs that have both 6V and 12V settings like some battery chargers?

There are 6V only portable battery "jump boxes" out there, just have to try a websearch..

 

But personally, to me, portable jump boxes are a waste of money, much, much cheaper to keep your vehicle (6V or 12V) in good working order. Checking battery condition is easy and cheap, costs nothing.

 

So far myself, for nearly 35 yrs I have never been stranded by a dead battery, dead starters yes, other failed parts yes, but not dead batteries. I have worn out a lot of batteries, they often give warning signs of sluggish starts when temperatures get cold. Just replaced a battery in of one of our modern vehicles last week and replaced with new battery. Noticed the starter was sounding rather slow in the morning as we had a overnight low temp of 40F last week.. Checked the battery voltage at rest, 12V battery should have a min of 12.6V when fully charged, it was reading 11.8V at rest.. Bad cell..

 

Jump boxes, do require periodic recharging, so folks tend to charge them when they first get it, toss it in the vehicle trunk and forget about it for yrs until they actually need it.. By that time the jumpbox battery is partially or fully discharged..

[John348]

The biggest culprit I have found in 6 volt systems is the disc in the solenoid, that seems to get pitted up and causes a bad connection. A well-maintained system works fine, but as pointed out by other electricity seems to be a weak point for many, even for those who claim to be professional mechanics.

[John_Mc]

3 hours ago, Rusty_OToole said:

We get queries all the time from people wanting to change 6V cars to 12V, add power steering, replace the complete front suspension, replace the engine with an OHV V8 and other "upgrades". Invariably they are amateurs who have no idea what they are talking about, probably influenced by some equally ignorant friend. Also invariably, it would be better easier and cheaper to fix the car properly than gut it like a trout.

Could not agree more……..instead of “upgrade”, how about using the term “changed”.

[wayne sheldon]

5 hours ago, Sparkydave said:

My calibrated finger told me there was something seriously wrong with the starter and solenoid connections as they were hot after just a few seconds of cranking. 

 

I worked in communications  systems contracting for over thirty years. We did it all, from digging the trench to the top of the tower, and all the cutting edge technology in between. Underground locating, commercial satellite receiving, early digital transmissions, forensic studies of failures, high power systems to subcomponent electronics, been there, done that.

All that, and one of my favorite methods of locating failure points was to let a system cool. Then stress it for a couple seconds and then quickly run my fingers over the wiring. I often recommend doing that on common automobile problems. Usually with a warning. You see, there is this little scar on my left index finger. Been over fifteen years now, and that little half moon scar is nearly gone, but I can still see it. My daily driver car had developed an intermittent failure. It would act up. I was in a hurry and all I had to do was slam my hand onto the fender of the car and be on my way. So, one day when I wasn't in a rush, and the car was cold, with the hood carefully opened I started the car and then shut it off. I ran my fingers around the battery cables and starter and - - . The control wire post to the starter solenoid was so hot it branded my finger when I touched it. By the way, it was a 12 volt electrical system car.

 

I also firmly believe in cleaning up a 6 volt system, not molesting it into a 12 volt mess.

[60FlatTop]

5 hours ago, joe_padavano said:

As a very hands-on motorhead who is also an aerospace engineer,

As one who has supported aerospace engineers I figure there are some 5V microprocessors and 1000 Ohm resistors a long way from home and operating just as well as the 5V power supply on this PC I am using.

 

Last week I was on the tech line with Honneywell International looking for the proper thermostat to operate the 750 milivolt gas valve on my home furnace. I think I was born in the wrong hemisphere.

 

12V cars? They are just a product of the Korean war shortages.

 

Like they say: 6V car systems ain't rocket surgery.

Edited September 23 by 60FlatTop (see edit history)

[EmTee]

8 minutes ago, 60FlatTop said:

Last week I was on the tech line with Honneywell International looking for the proper thermostat to operate the 750 milivolt gas valve on my home furnace.

You wouldn't have that problem if you had ditched that dinosaur for a cold-climate heat pump like the one that "says a lot" on those radio and TV commercials... 

[edinmass]

I’ll respond to the 6 vs 12 by saying this. Any of the great collections do not have any cars converted to 12 volts. The most sophisticated and educated collectors simply keep their cars stock. Does anyone think a purchaser of a 1930 Cadillac V-16 would have tolerated a slow cranking or hard starting car? Do you think Clark Gable would have driven a blowen SJN Duesenberg if it was unreliable? Properly maintained and serviced cars are absolutely reliable. On the last Model J tour, we ran a JN for 750 miles in four days and I never opened the hood. Never added water. Only checked the air pressure. Properly serviced cars don’t need much attention.

[trimacar]

To add to Ed’s post, exactly, does one seriously  think a “slow starting” car would sell?

 

The culprit, usually, is that 6 volt cars were grounded to the frame.  A frame riveted or bolted together, meaning nice clean steel from the factory.  As Joe mentions, corrosion at those points is self perpetuating.

 

Have your starter rebuilt correctly, not just “good enough”.

 

Run a ground directly to your starter motor, using heavy cables.

 

The difference is incredible.  Driving my Pierce, I’m at the Glidden, turns over incredibly fast as it did when new.

 

If one has lighting trouble, run a ground to each light.  A lot of trouble with big rewards, ask the guy who makes your new wiring harness to include grounds.

 

Yes a little wet on the tour, picture after Pierce unloaded.  Not driving, static, just where Suburban wipers stopped.

[joe_padavano]

41 minutes ago, 60FlatTop said:

As one who has supported aerospace engineers I figure there are some 5V microprocessors and 1000 Ohm resistors a long way from home and operating just as well as the 5V power supply on this PC I am using.

There are. What you are overlooking is that the connections to those parts were made using MIL-SPEC connectors that in some cases cost more than our cars. These connectors have gold-plated terminals specifically to avoid the voltage drops I'm talking about. The switches are all solid state devices, so no contacts to pit with operation and increase resistance. Prior to launch the probes are maintained in a completely controlled environment and once launched, they are effectively "vacuum-sealed", so there definitely isn't any moisture or grease to cause the connections to become more resistive. Oh, and considering that many of those systems operate on milliwatts, I doubt those components are pulling the amps that a 6V starter motor or headlight are pulling.

[nzcarnerd]

On this side of the Pacific the primary reason for changing to 12 volts is that 6 volt batteries cost twice as much and don't last as long.

[joe_padavano]

I said I was espousing the pragmatic approach. 😁

[Paul Dobbin]

35 years ago I bought my 6 Volt 1966 VW Bug.   It had lived it's entire life (23 years) as a 6 Volt VW in a retirement trailer park in Florida.

Owned by an elderly couple since 1966 it was kept in a carport until the old man died and the wife drove it until she went in a nursing

home.   The owner of the trailer park bought the trailer and the VW for a song.   Finding the battery was dead, he installed a 12 Volt battery

and sold the car to me.   I found  the starter turned the engine over faster than any of my previous VW"s and the headlights and turn signals were really bright too.    I fixed all that with a new 6 Volt battery and a new 6 Volt ground cable.   Then we enjoyed the car for 34 years on many AACA Tours, all with a 6 Volt electrical system.

[Rusty_OToole]

7 hours ago, joe_padavano said:

It's not rocket science (and yes, I am qualified to say that). I'll defer on the oddball issues like the Chrysler transmissions and the OD trans solenoids, but for the basic stuff, this is not the big deal that everyone makes it out to be. Sorry, but that has not been my experience.

Joe it may not be a big deal on cheap cars like Fords and Chevs that used vacuum wipers, had no radio or other electrical accessories but as you point out, can get very complicated on well built cars like Chrysler products and luxury makes .

[Sparkydave]

Thanks all, interesting discussion.  My dad had made some minor changes to his car, though they were relatively discreet.  For example, he didn't like the vacuum-powered wipers stopping on hills, so he scrounged the electric wiper motor and switch from a 1950s Chrysler, though I found he saved the old wiper motor and switch in his parts stash so he could always change it back.  Neat thing is the new wiper switch blends in well with the rest of the dash, so it doesn't look out of place unless you're familiar with Lincolns.  I'm not opposed to making improvements for safety or to overcome some known deficiencies.  My MG had a dead electronic ignition when I bought it from a friend of mine.  Come to find out that factory electronic ignition was notoriously unreliable, and word on the street was the ignition modules were so bad that it wasn't a question of if it was going to fail but where and when it was going to leave you stranded.  I replaced it with a Pertronix, but I tucked it neatly inside the distributor and used the wiring harness from the old system, so unless you look under the distributor cap, nothing looks different.  Even if it had still been working, I probably would have replaced it as British Leyland eventually started replacing it with a completely different system.

[joe_padavano]

9 minutes ago, Sparkydave said:

 Come to find out that factory electronic ignition was notoriously unreliable, and word on the street was the ignition modules were so bad that it wasn't a question of if it was going to fail but where and when it was going to leave you stranded. 

Wait! Are saying that British electronics are unreliable? I'm shocked, SHOCKED I tell you! 😲

 

(Yeah, pun only partly unintended... 😆)

 

Oh, what you really needed was this:

 

[wayne sheldon]

2 hours ago, joe_padavano said:

using MIL-SPEC connectors that in some cases cost more than our cars. These connectors have gold-plated terminals specifically to avoid the voltage drops I'm talking about.

 

The important part of that sentence is "MIL-SPEC". Even beyond "MIL-SPEC"? Know what your "MIL-SPEC" is. Most "gold connectors" are NOT plated in gold (the metal). MOST "gold" connectors are "anodized gold", most of which is aluminum based! While anodized gold plating is corrosion resistant, it is far from corrosion proof! I know from too much personal experience that most supply company's personnel do not know the difference. 

One of the rare (only?) time I needed a true gold plated connector? I knew at first glance the connectors supplied were not gold (except in the color sense), and demanded proof. Instead of the real gold plated connector, I did get an apology after the supplier found out I was right.

 

In a more down to Earth sense, when I go to buy brass rivets for antique automobile brake work? I take a strong magnet with me. About half the times, the clearly marked on the package "brass rivets" turn out to be brass plated steel rivets. The employees almost never know.

 

 

Edited September 24 by wayne sheldon
I hate leaving typos! (see edit history)

[Land24]

I don’t believe you switch the charger cables around as was stated in the first post

[joe_padavano]

39 minutes ago, wayne sheldon said:

 

The important part of that sentence is "MIL-SPEC". Even beyond "MIL-SPEC"? Know what your "MIL-SPEC" is. Most "gold connectors" are NOT plated in gold (the metal). MOST "gold" connectors are "anodized gold", most of which is aluminum based! While anodized gold plating is corrosion resistant, it is far from corrosion proof! I know from too much personal experience that most supply company's personnel do not know the difference. 

One of the rare (only?) time I needed a true gold plated connector? I knew at first glance the connectors supplied were not gold (except in the color sense), and demanded proof. Instead of the real gold plated connector, I did get an apology after the supplier found out I was right.

 

In a more down to Earth sense, when I go to buy brass rivets for antique automobile brake work? I take a strong magnet with me. About half the times, the clearly marked on the package "brass rivets" turn out to be brass plated steel rivets. The employees almost never know.

 

 

Read MIL-DTL-38999, specifically Series III space grade. There is no anodizing or aluminum on the contacts. The table below are the available options for the contacts, and I can assure you that the ones we use on spacecraft have gold plated contact pins and sockets (styles G and U). The connector bodies themselves are typically passivated stainless steel.

 

 

 

[wayne sheldon]

1 hour ago, joe_padavano said:

Read MIL-DTL-38999, specifically Series III space grade. There is no anodizing or aluminum on the contacts. The table below are the available options for the contacts, and I can assure you that the ones we use on spacecraft have gold plated contact pins and sockets (styles G and U). The connector bodies themselves are typically passivated stainless steel.

 

 

I am not in any way questioning your interpretation of any MIL-SPEC or application thereof. True gold plating of connectors of many types are far better than basically anything else anywhere, on Earth or in space.

What I am saying is that most non-MIL-SPEC  in the general marketplace is a whole lot more about appearances than about facts. It is much more about marketing hype and presentation than it is about the truth of what something is. Look at almost any online supplier of electronic equipment and home audio/video components or supplies. Hundreds of various connector cables and fittings touted as being "gold". Probably less than one percent of them have any real gold anywhere in them.

Thirty and more years ago, even the commercial suppliers we often dealt with rarely understood that most of what they sold "gold" was not the metal gold.

The fact is, that actual gold plate is not all that expensive. A small simple connector might require a few pennies worth of actual gold. But big companies sell billions of small simple connectors. Even at pennies each, that is millions of dollars that can be saved every year by simple anodizing and presenting it in a way that most people will still pay several dollars more for a connector cable with maybe six anodized subcomponents in it.

[Frank DuVal]

10 hours ago, joe_padavano said:

Accessing all the terminals and splices is not trivial, especially for the ones under the dash. And when the corrosion is between the terminal and the wire (inside the crimp), well, that's a slippery slope to a new harness. 😉

On a typical 6 volt car, the large current connections are what?, 8 for the starter circuit? Two on the battery, one on the chassis, two on the ground connection chassis to engine block, two (or one) on the starter switch/solenoid and one on the starter itself. 

 

Most of these are readily accessible! And two of them will be fixed when converting to 12 volts, so that is only 6 more connections to clean. And see next comment, voltage drop is still an issue even though it might start on 12 volts. FIX IT! Those acid eaten big cables will continue to deteriorate on 12 volts too....  Just delaying the inevitable.

 

If the connections under the dash are bad, the a new harness is needed EVEN if you convert to 12 volts, as this is a fire waiting to happen!😮  Voltage drop across a connection does not get better with age, and V * I = Watts of heating. FIX IT!

 

12 volts is a crutch, period, just like those weird 8 volt batteries! Just throwing parts at a problem rather than fixing it.🤬

 

You ARE right on the D38999 connectors, I've used lots of them. Not on cars, hmm, well maybe on winch remote connectors....  Race car  builders use them a lot!  Gold over nickel, with stainless steel holding the females (sockets) tight.👍     

Edited September 24 by Frank DuVal (see edit history)