positive ground to negative ground

[frijolito]

Hello everyone. I'm trying to convert over from positive ground to negative ground. Still keeping it 6 volts. I've read this great article from Fifth Avenue Garage and was wondering if its all I have to do. Any help with changing over or the steps it takes would be helpful. 

 https://fifthaveinternetgarage.blogspot.com/2017/06/changing-your-electrical-system-from.html

Edited July 7, 2020 by frijolito

[Sam Buchanan]

Turn the battery around so you can connect the ground cable to the negative post of the battery. Leave the other cable disconnected while you swap the wires on the ammeter. Once that is done connect the positive post of the battery to the other cable.

 

The article states it is not necessary to switch the wires on the ignition coil. You will get various opinions on this but the coil will function either way.

 

That's it.

[Sniper]

I noticed the coil was wired backwards on my 51, fixed that but there was no noticeable difference.  Now on a different brand (VW) the spark was so weak it would not fire the engine, corrected that and it fired right up. 

[TodFitch]

Curious about the reason to change polarity if keeping 6v. I don’t see an advantage.

[Sam Buchanan]

The primary advantage for changing polarity on my car was because that is the way I wanted it.  ?

[frijolito]

15 minutes ago, TodFitch said:

Curious about the reason to change polarity if keeping 6v. I don’t see an advantage.

mostly because I'm running 12volt pumps that won't work on positive ground. 

[Go Fleiter]

The Radio may be polarity sensitive. put a fat (!) bridge rectifier if so.

I don´t know which type of e- motors are used:

E- motors can have the field and armature windings inline or have a permanent magnet (sorry, I don´t know the correct technical terminology).

The heater fan may run reverse, depends on the style.: Try if airstream comes right out

Wiper motors too, which would be irrelevant: but try if they reach the parking position.

 

[milo9rat]

I kept my 6V wiper motor when i changed to 12V neg. and used one of these and wiper works great and parks...

[Sniper]

And one of these is what?  Got a link?

[maok]

1 hour ago, milo9rat said:

I kept my 6V wiper motor when i changed to 12V neg. and used one of these and wiper works great and parks...

your 6v wiper motor would have worked fine without that step-down transformer. It would just run twice as fast.

[Sniper]

It's not a step down transformer, transformers don't work for DC.

 

As for running your 6v wiper motor on 12v, I did that, bad idea.  I tends to beat the linkages up

[frijolito]

In 1939 my wiper motors are still vacuum. 

[Plymouthy Adams]

8 hours ago, maok said:

your 6v wiper motor would have worked fine without that step-down transformer. It would just run twice as fast.

which would be somewhat slower than many of todays wiper systems...⛈️

[milo9rat]

Sniper.. How can it beat the linkage up?? It doesn't run faster, runs at the same speed as it did on 6V....

[milo9rat]

This is what I bought.. It works great, wiper runs at original speed and the park works too.. At $20 bucks, can't go wrong in my opinion....

Edited July 10, 2020 by milo9rat

[desoto1939]

8 hours ago, frijolito said:

In 1939 my wiper motors are still vacuum. 

Yes that is correct for the 1939 Plymouth.   The 1939 Chrysler, Desoto and Dodge all came standard with the Autolite electrical wiper motor.

 

The lower line of Plymouth retained the trico vacuum wiper motor system.

 

Rich Hartung

desoto1939@aol.com

[kencombs]

1 hour ago, milo9rat said:

Sniper.. How can it beat the linkage up?? It doesn't run faster, runs at the same speed as it did on 6V....

Not Sniper but, according to your post, the wipers on running on the 6v output of the device (resistor pack) that is installed not 12v.  I ran a 6v motor on 12 once just to try it:  Fast!  and would surely put a strain on mechanical linkages.

[Sniper]

6 hours ago, milo9rat said:

Sniper.. How can it beat the linkage up?? It doesn't run faster, runs at the same speed as it did on 6V....

 

I think you are thinking of how your wiper runs after you put that DC to DC converter in.  Which means your 6v wiper motor is running on 6v as designed.

 

I said running a 6v wiper motor on 12v was a bad idea.,  BTDT.  I ended up building a current limiting circuit to slow it down.  Works good. 

 

A link to what I think you bought

 

https://www.ebay.com/itm/DC-12V-24V-to-6V-20A-120W-STEP-DOWN-DC-DC-Power-Converter-Regulator-/390805682663

[maok]

Yes, 'transformer' is not the correct terminology, however, the DC is converted into an AC source (a square wave by switching the dc 'on and off') then converted to the appropriate voltage, up or down then converted back to DC in these dc - dc converters.

 

If the linkages are free and not binding, I can't see how the extra speed from a small DC motor would damage them.  I have never had any issues running a a 6v wiper motor on 12v, but my wipers have only been single wiper arms.

[Sniper]

Single arm wipers don't have linkages, so any experience with those is not relatable.

 

Whether you can see how it would happen or not is also not relatable, it happens from direct observation and experience.  As they say, theory is fine, till it meets reality.

[maok]

And one failed attempt does not make one an expert.

 

Limiting the current does not slow it down,  voltage level controls the speed.

[greg g]

Some one wiser than me said you can use the chassis as ground for both positive and negative systems.  If this is indeed the case, 12 volt neg accessories can be powered from a dedicated source like a battery in the trunk, with negative grounded to frame or body sheet metal. Then the accessories can be wired as one normally would from dedicated power through the switch and then either self grounded through the mount r wired to a body or frame bolt.

[Plymouthy Adams]

when doing this one has to be very careful taking electrical measurements and just where they have the test leads....you will get some very funky reading......dual charging systems just have never made sense to me 

[Sniper]

On 7/11/2020 at 6:02 PM, maok said:

And one failed attempt does not make one an expert.

 

Limiting the current does not slow it down,  voltage level controls the speed.

 

How about this then, I finished my electronics training in 1984 and have 36+ years experience.  That qualify as an expert for you?

 

It is apparent to me you know little about Ohm's law, the basic foundation of electricity and electronics.

 

What determines Voltage? Current times resistance.  The wiper motor's resistance does not change so in order to change the voltage you have to change the current.  You limit the current, you limit the voltage, period. 

 

So go tell my wipers that limiting current does not work.

 

https://youtu.be/Ip-mtPqGBd4

[Sam Buchanan]

I have no formal electronics training..........can somebody come swap out this battery for me???    ?

 

Grumpy old men.......................