Author Topic: 6 volt or 12 volt  (Read 16638 times)

Offline warmshed

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Re: 6 volt or 12 volt
« Reply #60 on: 18.02. 2014 17:39 »
 
[/quote]
Totally agree with going 12V but I am not aware of any particular issue with +ve earth for powering GPS and phones etc.  As long as they are connected through some connector or similar mounting hardware, it should be possible to wire them accordingly to work with +ve earth.  Only issue I see could be with electronic ignition if it is "grounded" through the engine/frame earth.  12V LED bulbs are readily available but the ones I have used are polarity sensitive.  Not sure if all LED's are polarity sensitive though.
[/quote]

Keith, most LED bulbs are polarity sensitive. They are normally all made as  -Ve earth which is why the bulbs via Goff (good supplier) are more expensive, he makes them for people with +ve earth, they are rarely available from most other sources, certainly all the cheaper ones are available only as -ve earth.

The majority of electronic ignitions are supplied as -ve earth, you will limit your choice if you go +ve earth.
 

Offline Ethelred

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Re: 6 volt or 12 volt
« Reply #61 on: 18.02. 2014 19:05 »

Just curious, but is there any electrical advantage/disadvantage between positive and negative earth (apologies for being a bit off topic)
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Online RichardL

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Re: 6 volt or 12 volt
« Reply #62 on: 18.02. 2014 19:29 »
This is a great question and I am still trying to figure out what part of it is most important and why, based on what I've just read. Apparently, battery corrosion is less when the positve terminal is earthed. Also, it appears that spark is better when it jumps from the electrode to earth. Then (again, I just read this), our magnetos send opposite polarity spark to the cylinders, so this aspect might not matter. (Groily or other magneto mavins will please correct me if I've read that wrong or it does not apply apply to K2F.).

I put this stuff out there so I can be slapped-about with corrections and learn thereby.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline KeithJ

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Re: 6 volt or 12 volt
« Reply #63 on: 18.02. 2014 19:37 »
Heard you should swop plugs over as one side deposit conductor material and the other erodes its?  Also, it was something to do with the way current was thought to flow.  Historically it was from +ve to -ve but more recently thought to be the other way, who knows?
'59 A10RR + Second engine

Online trevinoz

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Re: 6 volt or 12 volt
« Reply #64 on: 18.02. 2014 20:50 »
Would you all believe that 6V bulbs are readily available from India and are cheap as chips.
I bought about 30 for myself and others and the landed price came to somewhere between A$2 - A$3 each.
They are motorcycle pre-focus type (filaments in the right position) and can also be had in 12V.

Trev.

Online groily

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Re: 6 volt or 12 volt
« Reply #65 on: 18.02. 2014 22:07 »
On the pos/neg polarity of sparks, if you've got a single, negative sparks are preferable - for being stronger - because electrons like going from the centre electrode to the earth one if they can.  But not an option we get with a twin mag, as one spark is always going to be positive. Folk say you should swap the plugs round now and again to compensate, but have to say I never do. The plugs in my A (NGKs as it happens) have been in there for 30K+ miles now, and you'd have to be a lot smarter than me to know which had run pos and which neg. They both look good as new.
Just a throwaway line, but I reckon a lot of plug trouble is actually symptomatic of other issues with the mag (or the carb). (But I agree some plugs do prematurely fail for no obvious reason.)

On the pos/neg earth Q for the electrical system generally etc, I really dunno. 'They' said years ago, and the 'continentals' followed it, that negative earth avoided corrosion of bodywork on cars, and didn't I read once that Rolls Royce were always Neg earth? But frankly, a lot of cars just rusted away whatever you did after they'd abandoned chassis. None of my bikes ever has (rusted away), despite terrible neglect, and I run pos earth, except on a couple of things with electronic ignition conceived for neg earth. I don't really think it makes a lot of odds.

But I'm sorry your mag's died again Morris - that's depressing. They shouldn't die like that, they really shouldn't!
Bill

Online bsa-bill

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Re: 6 volt or 12 volt
« Reply #66 on: 18.02. 2014 23:10 »
The good news with LEDs is they are quite robust and connecting them up the wrong way wont harm them, they are polarity sensitive in as much as they only work one way but all that is necessary is to reverse the connection 
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline warmshed

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Re: 6 volt or 12 volt
« Reply #67 on: 19.02. 2014 19:29 »
Only trouble is some lamp holders are connected to earth so you cant reverse the wiring.  I see some LED fittings (though rare), have diodes fitted inside them so you can fit them to either polarity

Offline KeithJ

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Re: 6 volt or 12 volt
« Reply #68 on: 19.02. 2014 20:02 »
'59 A10RR + Second engine

Online bsa-bill

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Re: 6 volt or 12 volt
« Reply #69 on: 19.02. 2014 20:34 »
Quote
Only trouble is some lamp holders are connected to earth so you cant reverse the wiring

True
Quote
have diodes fitted inside them so you can fit them to either polarity

Ah a diode in a Light Emitting Diode, wonder if they just double them up wired up each way so one will always work - obvious but still clever
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online morris

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Re: 6 volt or 12 volt
« Reply #70 on: 19.02. 2014 21:41 »
But I'm sorry your mag's died again Morris - that's depressing. They shouldn't die like that, they really shouldn't!
Agree. That's why it's going to be revived and be reused on the plunger!
The swingarm's magneto is still as was when I bought the bike. A wile ago the right plug refused to spark, so I took it part and found a dirty carbon coated slipring. Cleaned it up, renewed the brushes, but now it started to develop the same symptoms again.
When taking it apart I found that he who did the last overhaul didn't do a good job, so I'll be sending it to someone who knows what he's doing.
The swingarm is going to be converted to electronic sparking, mainly because I will be using it as a daily runner, and also a bit as an experiment because I want to know if it will behave any better.
Thanks for your kind words of condolence....
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'52 BSA A 10 Plunger
'55 MORRIS ISIS
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Offline Dynamo Regulators Mike

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Re: 6 volt or 12 volt
« Reply #71 on: 20.02. 2014 08:58 »

True
Quote
have diodes fitted inside them so you can fit them to either polarity

Ah a diode in a Light Emitting Diode, wonder if they just double them up wired up each way so one will always work - obvious but still clever

Actually the polarity insensitive ones employ four small diodes (in a bridge) to steer the current to the LED(s) in the correct direction. A small version of the familiar alternator rectifier, but tiny and only cost a few pennies/cents/sou.
Mike Hutchings
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Online groily

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Re: 6 volt or 12 volt
« Reply #72 on: 20.02. 2014 09:16 »
Glad you're going to revive the mag on your plunger Morris, and be interested how you get on with the new box of clever tricks. If the mag has got a mucky slipring again, then maybe the brush quality is the problem, as there are a lot out there that are too soft and leave deposits, despite lots of comments from unhappy owners that you'd think would deter people from selling them. The brushes must not 'write' like a pencil on paper, but should leave only faint traces. There have also been some pretty horrible sliprings out there over the years, and pattern HT pick-ups that leak from brand new, so I'm sure when you have the thing sorted out properly it will fine again! Good luck.
Bill

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Re: 6 volt or 12 volt
« Reply #73 on: 28.02. 2014 04:10 »
This is a great question and I am still trying to figure out what part of it is most important and why, based on what I've just read. Apparently, battery corrosion is less when the positve terminal is earthed. Also, it appears that spark is better when it jumps from the electrode to earth. Then (again, I just read this), our magnetos send opposite polarity spark to the cylinders, so this aspect might not matter. (Groily or other magneto mavins will please correct me if I've read that wrong or it does not apply apply to K2F.).

I put this stuff out there so I can be slapped-about with corrections and learn thereby.

Richard L.

It all goes back to steel hulled ships used in WW II.
They discovered that you could use eletrodes connected to the ships batteries to protect the hulls in place of the big chunks of zinc formally used.
Thus leaving more zinc for important things, like brass buttons for generals.
Post WW II some clot in the auto electricial trade decided that running + earth would stop cars & bikes rusting and they managed to convince every one that what works in full contact highly conductive salt water would also hold for partial contact less conductive rainwater & condensation.
Proper metallurgical research into galvanic corrosion proved this to be rubbish in the early 50's but the auto industry persisted with it .
there are some highly esoteric reasons why neg earth is better than pos earth but thr primary reason was to be consistent with domestic electricity.
Bike Beesa
Trevor

Offline Rich

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Re: 6 volt or 12 volt
« Reply #74 on: 28.02. 2014 20:30 »
I changed to 12 volt some time ago with the original dynamo, DV2 regulator, also running an SRM dynamo belt conversion for a better output at lower revs.  I will stay with 12volt as the electric starter requires 12 volt to work, need the electric start even having had a new right hip joint replaced 9 weeks ago!!