Negative Ground Conversion

JimC · Nov 24, 2015

kingcole said:
Hi to all.
Ok so I am ignorant but I cannot see what the benefits are that you will get out of changing from positive earth to negative, a load of hassle and expense maybe ?. I have a 1972 Mk3 750 which functions perfectly well on its original set up so why change if it aint broke.

No benefit whatsoever, unless you want LED lights, GPS, radar detector, radio, charge a cell phone, etc. All modern electrical devices require a negative ground. Although, there are some that say switching polarity will make a difference how a spark plug functions. There is also dissension among experts on which way current travels. When I was in the Navy electronics school, two theories were discussed. The conventional theory said current flowed from positive to negative, whereas the electron theory said the opposite. Filament bulbs work with either polarity, even with alternating current. Relays with a diode across the coil are polarity sensitive. Fortunately, few relays are wired as such.

Don't forget the zener diode the Commando uses for a regulator is polarity sensitive.

batrider · Nov 24, 2015

It does not matter which direction current travels (+ to - or - to +) as long as you are consistent in your calculations. I always think of electrons flowing towards positive (schooled in the 70's) but I recognize that some use the opposite convention and just go with it. Totally arbitrary.

Has nothing to do with this topic though.

JimC · Nov 25, 2015

It does not matter which direction current travels (+ to - or - to +) as long as you are consistent in your calculations.

It only matters, for our discussion, that devices that are positive supply and negative ground by design need a battery that has the negative post connected to ground ( frame or bus).

Deets55 · Nov 25, 2015

JimC said:
kingcole said:

Hi to all.
Ok so I am ignorant but I cannot see what the benefits are that you will get out of changing from positive earth to negative, a load of hassle and expense maybe ?. I have a 1972 Mk3 750 which functions perfectly well on its original set up so why change if it aint broke.

Click to expand...

No benefit whatsoever, unless you want LED lights, GPS, radar detector, radio, charge a cell phone, etc. All modern electrical devices require a negative ground. Although, there are some that say switching polarity will make a difference how a spark plug functions. There is also dissension among experts on which way current travels. When I was in the Navy electronics school, two theories were discussed. The conventional theory said current flowed from positive to negative, whereas the electron theory said the opposite. Filament bulbs work with either polarity, even with alternating current. Relays with a diode across the coil are polarity sensitive. Fortunately, few relays are wired as such.

Don't forget the zener diode the Commando uses for a regulator is polarity sensitive.

Jim,
Positive ground LED bulbs are available, A lot LED headlight bulbs can be fitted either way. Unless any other equipment you might want to use is case grounded an attached to the frame or any other grounded point it will work with out any issues. You just have to keep track of your + & -'s. Also be careful of the type of plugs you use sometimes the exposed pin can cause a short if it accidental gets grounded. Use fuses to protect you add on's. I share my GPS with my bikes and cars, I also have a USB tap for my phone.

JimC · Nov 25, 2015

Deets55 said:
JimC said:

kingcole said:

Hi to all.
Ok so I am ignorant but I cannot see what the benefits are that you will get out of changing from positive earth to negative, a load of hassle and expense maybe ?. I have a 1972 Mk3 750 which functions perfectly well on its original set up so why change if it aint broke.

Click to expand...

No benefit whatsoever, unless you want LED lights, GPS, radar detector, radio, charge a cell phone, etc. All modern electrical devices require a negative ground. Although, there are some that say switching polarity will make a difference how a spark plug functions. There is also dissension among experts on which way current travels. When I was in the Navy electronics school, two theories were discussed. The conventional theory said current flowed from positive to negative, whereas the electron theory said the opposite. Filament bulbs work with either polarity, even with alternating current. Relays with a diode across the coil are polarity sensitive. Fortunately, few relays are wired as such.

Don't forget the zener diode the Commando uses for a regulator is polarity sensitive.

Click to expand...

Jim,
Positive ground LED bulbs are available, A lot LED headlight bulbs can be fitted either way. Unless any other equipment you might want to use is case grounded an attached to the frame or any other grounded point it will work with out any issues. You just have to keep track of your + & -'s. Also be careful of the type of plugs you use sometimes the exposed pin can cause a short if it accidental gets grounded. Use fuses to protect you add on's. I share my GPS with my bikes and cars, I also have a USB tap for my phone.

I realize LEDs can be found that are negative supply, but I would think positive supply LEDs are much more plentiful and probably cheaper. I'm totally aware of isolating a positive supply device from ground and using a negative battery supply. It would just seem a whole lot simpler to change from a positive ground to a negative ground electrical system and not have to worry about plugs and inadvertent grounding of electrical device cases. Kind of a plug n' play mentality.

Jeandr · Nov 27, 2015

Why are all motorcycles left foot shift and right foot brake NOW? standardisation!

Why go to -Ve to frame?

1- everyone else is like that (again standardisation)
2- keeps some idiot from attaching booster cables like a car and frying your wiring loom (I have seen it)
3- as mentionned by many, any electronic add on with negative to case is guaranteed to work
4- also mentionned many times, LED lights bought anywhere cheaper will work.

Jean

Negative Ground Conversion

JimC

batrider

JimC

Deets55

JimC

Jeandr

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