View Full Version : Negative or positive earth?
Shane Scanlan
2nd September 2020, 03:44 PM
Hello again.
Today we're confused about electrics.
In particular, all the references I can find say that my 1960 Series 2 109 should have a positive earth.
And yet the negative battery terminal is connected to the chassis.
My questions are:
* Does this just mean that the previous owner got this wrong and it should just be swapped without any dire consequences?
* Or does this setup suggest a plague of serious problems are coming my way?
* If so, what are they?
Thanks
Shane
Homestar
2nd September 2020, 04:20 PM
A lot of early Series vehicles that started out their life as positive earth have been changed over the years to negative earth - one of the reasons for this would be when fitting a modern alternator over and old generator, they are all negative earth units. If your vehicle has an alternator rather than a generator then swapping back would cause ‘Bigga badda boom’ as they say in the Fifth Element.
If you want it all original and you have a generator in there then it could be swapped back but there will be a few things you need to check before doing so - one fo which is the wiring to the gen and regulator, but I can’t remember exactly what changed here - only going off memory from other threads.
If you have no issues with how it is now, I’d just leave it, it makes no difference to the vehicle.
Shane Scanlan
2nd September 2020, 04:36 PM
A lot of early Series vehicles that started out their life as positive earth have been changed over the years to negative earth - one of the reasons for this would be when fitting a modern alternator over and old generator, they are all negative earth units. If your vehicle has an alternator rather than a generator then swapping back would cause ‘Bigga badda boom’ as they say in the Fifth Element.
If you want it all original and you have a generator in there then it could be swapped back but there will be a few things you need to check before doing so - one fo which is the wiring to the gen and regulator, but I can’t remember exactly what changed here - only going off memory from other threads.
If you have no issues with how it is now, I’d just leave it, it makes no difference to the vehicle.
Thanks for that. Happy to leave it if it makes no difference.
And the vehicle has a generator.
1950landy
2nd September 2020, 08:11 PM
A lot of times the polarity gets change is if a radio has been fitted that is negative to earth. Positive to earth radios are harder to find these days & not all the older ones had a polarity switch .
mox
8th September 2020, 09:24 PM
A lot of times the polarity gets change is if a radio has been fitted that is negative to earth. Positive to earth radios are harder to find these days & not all the older ones had a polarity switch .
I have a 1961 Series 2 LWB acquired from estate of a relative who owned it for about 50 years. It still has the original type generator. With negative earth. Presumably was positive earth originally but changed as is evidence it has had a two way radio installed in the past. Presumably at least when the owner was the local volunteer fire brigade captain. I recall seeing on www.expeditionlandrover. info instructions on how to alter wiring for old Land Rovers with positive earth to negative earth. Looked fairly simple. Presumably still there for those who want to check.
W&KO
9th September 2020, 05:52 AM
I have a 1961 Series 2 LWB acquired from estate of a relative who owned it for about 50 years. It still has the original type generator. With negative earth. Presumably was positive earth originally but changed as is evidence it has had a two way radio installed in the past. Presumably at least when the owner was the local volunteer fire brigade captain. I recall seeing on www.expeditionlandrover. info instructions on how to alter wiring for old Land Rovers with positive earth to negative earth. Looked fairly simple. Presumably still there for those who want to check.
Link did quite work, guessing this is the article.
Land Rover - Pos to Neg Polarity conversion (http://www.expeditionlandrover.info/polarityConversion.htm)
JDNSW
9th September 2020, 06:11 AM
As above. Landrovers up to 1967 were positive earth, but by 1970 most polarity sensitive accessories were negative earth only, and since the changeover is simple and easy, most have probably already been changed. The only wiring change is to change the battery clamps and reverse the ammeter connections. Then reverse the remnant magnetism in the generator, most simply by momentarily closing the cutout points with the engine stopped.
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