The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Guy Wilson on 26.03. 2012 13:38

Title: 12 volt negative earth conversion
Post by: Guy Wilson on 26.03. 2012 13:38
Hello All,
This has been discussed at length and I'm sure there is a very comprehensive answer somewhere amongst the posts, however I can't find one!
Can any one direct me to an account of what's involved converting from 6 volt positive earth to 12 volt negative
many thanks
Guy
Title: Re: 12 volt negative earth conversion
Post by: muskrat on 26.03. 2012 19:46
G'day Guy,
               converting reg (dvr2 or equivalent) or re-wound dynamo, battery, globes etc, and flash dynamo to - earth.
Thats about it.
Cheers
Title: Re: 12 volt negative earth conversion
Post by: bsa-bill on 26.03. 2012 19:51
going negative earth would confirm to 99.9% of the rest of the world but make no difference to performance or other aspect to your bike.
viva le difference as they say Rodney
Title: Re: 12 volt negative earth conversion
Post by: Guy Wilson on 27.03. 2012 06:06
Thanks Bill, so you're saying it makes no difference and I should probably keep it as positive earth? My Triumph Trophy is a positive earth and doesn't seem to mind....
Guy
Title: Re: 12 volt negative earth conversion
Post by: a101960 on 27.03. 2012 09:34
I changed to 12 -ve earth so that I could fit LED's to my speedo and rev counter. I also have an LED stop/tail and front pilot LED (which is very bright). The change from +ve to -ve earth is very easy as muskrat says. If you have the 6v mechanical regulator just reverse the battery connections and flash the dynamo. To convert to 12v you will need to fit an electronic regulator (My preference would be the DVR2) then same as described for the 6v conversion reverse battery leads, flash the dynamo, and change your lamps to 12v. Fitting a belt drive to the dynamo would be a good idea ( I have done this) and there is no real need to have the dynamo rewound for 12v operation. The E3L is more than capable of delivering 12v reliabley.

John
Title: Re: 12 volt negative earth conversion
Post by: Guy Wilson on 27.03. 2012 10:40
thanks Bill, John, Muskrat,
I was already looking at the belt drive conversion and the DVR2 replacement regulator, so you've just convinced me. The original chain drive was missing in the box of bits that I'm building the bike up from. Its been a long slog as most of the major parts were sourced locally form various locations around Kenya. I've now got it pretty much together and complete. Its free standing and the engine cranks and sparks etc. Its the small stuff that's taking the time, not that I thought it wouldn't, so I'm looking for the most practical solutions for things like the generator and rewiring etc.
I've given myself a deadline of this September, which was revised from last september to a least ride down the escarpment to the Masai plains...we shall see, I'll post picture of me ether succeeding or failing by September,
Guy
Title: Re: 12 volt negative earth conversion
Post by: iansoady on 27.03. 2012 11:47
I must say that positive earth always confuses me a bit as my car and modern bike are both negative and I have to change my mindset when working on the A10. If I was to do it again I'd convert to negative earth.

I would only change to 12 volt if I intended doing much night riding.
Title: Re: 12 volt negative earth conversion
Post by: muskrat on 27.03. 2012 13:31
Funny, I got the A65 cheap as the owner couldn't get it started. He had the battery in the wrong way, Boyer ign wouldn't work at -ve.
Cheers
Title: 12 volt negative earth conversion
Post by: Guy Wilson on 23.01. 2020 15:38
G'day Guy,
               converting reg (dvr2 or equivalent) or re-wound dynamo, battery, globes etc, and flash dynamo to - earth.
Thats about it.
Cheers
I've read through this old thread. I've been using a total loss electrical system for a couple of years and don't have my dynamo connected in the circuit. If I convert to - earth, is it just a matter of switching the terminals on the battery? I want to use LED bulbs is the reason for the change..

Guy
Title: Re: 12 volt negative earth conversion
Post by: morris on 23.01. 2020 20:16
G'day Guy,
               converting reg (dvr2 or equivalent) or re-wound dynamo, battery, globes etc, and flash dynamo to - earth.
Thats about it.
Cheers
I've read through this old thread. I've been using a total loss electrical system for a couple of years and don't have my dynamo connected in the circuit. If I convert to - earth, is it just a matter of switching the terminals on the battery? I want to use LED bulbs is the reason for the change..

Guy

Explanation how to flash in Beezermacs reply;
https://www.a7a10.net/forum/index.php?topic=11474.msg87177#msg87177
Dynamo belt drive and DVR2 highly recommended.
If you’re not on electronic ignition you don’t really need led bulbs. A dynamo In good order will be perfectly capable of running all the lights even on 12v
Title: Re: 12 volt negative earth conversion
Post by: Guy Wilson on 24.01. 2020 07:05
Thanks Morris, one day..maybe this week, I'll get around to connecting the dynamo and seeing it works .. I've been running on a battery only for the last couple of years... my battery lasts about 3 weeks using the brake light and horn an occasionally the sidelights.. The batteries a bit crap too, so I though LED's would help. I have them on my BMW which is - earth ..
Guy
Title: Re: 12 volt negative earth conversion
Post by: Rex on 24.01. 2020 10:31
I never see any confusion with pos or neg earth. Just make sure that the cable going to the battery positive is red and the neg is black. It's of no consequence whether the lead is 3" long and goes to earth, or much longer and disappears into the loom.