Packard Forum Index » Post-War (1946-54)

A battery polarity question-the guy I rescued my 53 Patrician from tried to get it going at one point and installed the battery backwards-negative ground I don't think he tried very hard or very long to make it go, but I'm wondering what kind of damage might have been done. The starter bench tested OK and I seem to have what I need for lights and ignition. Still cleaning up the carb so have not run it yet to see if it charges.
Thanks
MIkeG

No damage would have been done to anything on a normal Packard. Only possible thing might be anything aftermarket added with sold state electronics including the Packard radio if it had it's vibrator or rectifier tubes replaced--all original radio or if kept off, no problems.

The only thing I can add to HH56's 100% correct answer is that whenever you take it to someone who might "service" it, put a sign in red on the battery stating that this is a POSITIVE GROUND car.

Of course, you can convert it to negative 6V ground if you want, but that's an entirely different thread that I believe has been covered in at least the V-8 Forum for 12V.

Craig

Thanks for the info. As far as changing polarity-why bother? I have as many 6V positive as 12V negative vehicles. Perhaps I can get a more definitive answer here that nobody on the Model A or BSA motorcycle forums has given. Since most vehicles produced through the 50s were positive ground why was the switch made to negative?

You're sure right about answers as to why the change being all over the place. Everything from Henry Ford decreed it to positive ground being more corrosion prone to efficiency of electron flow. Probably the one making the most sense is the govt wanted all to be the same--just like they did with the transmission shifter layout a few years later. One of those mysteries that will go on I guess----

I am not positive (no pun intended) as to the actual reasoning of the manufacturers but experience tells me that Positive ground electrical systems work well when everything is new and all components ground as designed. As the vehicles get older, parts rust/corrode/get loose, etc. components tend to loose their grounds and to become either inoperable or intermittent, if you will. The negative ground system with its input and ground wiring tends, I think, to be more dependable and easier in some cases to diagnose over the long run. Today, most mechanics have never seen a Positive ground system and some tend to do strange things to them in their ignorance.

I don't believe one is any more or less reliable or easy to diagnose than the other. Keeping terminals and connections clean should result in the two methods performing essentially equally. The only difference I've observed over the years is that in a poorly maintained condition, positive-ground systems tend to generate their electrical corrosion at the ground/engine block connection, and negative-ground systems tend to get theirs at the battery terminal.

Quote:



My two cents worth here: My electronics background goes back to the early 50's. Growing up with a father with a EE degree from UC Berkeley I learned a lot about electronics from a very early age from him as well as going on to school myself. Except for a side trip into the Real Estate business in 1976 my entire living,from 1965 to date, was made in the electronics repair business. My first job out of high school was repairing mobile CB radio equipment as well as Tube type radio's such as the ones in our Packards. I can say that there is not the slightest difference to anything if you use positive or negative grounded to the car chassis. The only thing that changes is the wether the current flows to or from the chassis. The chassis of a car is nothing more than the common connection for the electrical system. Saves you from the necessity to run two wires to everything. Electron flow is from negative to positive. The electrons don't care which terminal of the battery is connected to the chassis. They will still flow
- to +.

I may not be saying this very well but the bottom line is there is no difference. The only thing I can think of is that in the early days UC Berkeley taught that current flow was + to - when most were teaching just the opposite. Again it makes no difference.

Are there any EE people that can say it in a better way. I know my father could but he is no longer with us.

Absolutely agree - no difference. The electrons "flow" both into and out of the chassis to be the "other wire" as you say. They don't really flow, they more "bump", so the question of (+ to -) or (- to +) is just a visualization/teaching convention. At least that's how I remember my EE electives.

Bob -

I understand and agree with what you're saying, but with a couple of exceptions.

First, I believe the generator must be properly polarized to match the ground. Otherwise, over the long term, you could damage the voltage regulator, which could then result in a burned up generator armature.

Second, as HH56 noted above, if you have upgraded to a solid state replacement for the rectifier or vibrator in the OE radio or added other solid-state aftermarket equipment, then polarity is a big issue.