The BSA A7-A10 Forum

Technical => Lucas, Electrical, Ignition => Topic started by: Housewiz on 15.12. 2012 17:51

Title: 6v to 12v conversion
Post by: Housewiz on 15.12. 2012 17:51
Who has had great luck converting 6v to 12v and what parts were used?  I saw the post on bulb choices, the conversion parts listed in that post, although I am in the dark about what the protocol is on converting the dynamo.

Just a little curious about what is needed to provide good lighting at night - not like it's going to anytime soon ai will be motoring around on my Frankencycle.

Thanks,

Steve
Title: Re: 6v to 12v conversion
Post by: warmshed on 15.12. 2012 18:54
Just get an electronic control box, DVr2 is what I have used and very pleased with.  Easy wiring just use the wires from existing regulator, only 4, so no electrical knowledge needed, just follow the instructions..  Put in the battery and change the bulbs. The horn will work fine with 12 volts, you may even hear it.

You can even use the regulator to work as 6 volts until you get round to getting a new battery. Only one wire difference.

Only decision to make is what earth polarity do you want, I would suggest -ve earth as most things you buy now like it this way round.
You may have to Polarise the dynamo to change the polarity, easy done, without the regulator connected, run a temporary wire from the non-earthed side of the battery (ie +ve if using -ve earth) and touch it on the F tag of the dynamo, it will flash with a spark.  Remove this wire and connect the regulator.  The "flashing" of the dynamo just changes the polarity of the magnetism of the field coil so it now generates the voltage in the required way. 

Any problems just list on here and help will follow.

Good luck.
Title: Re: 6v to 12v conversion
Post by: Triton Thrasher on 15.12. 2012 19:10
There is a disadvantage.

The headlight will soon flatten the battery and go very dim, in urban traffic conditions, because the 6V dynamo does not cut in at 12V until higher rpm than when regulated to 6V.  Many riders use a 10W halogen pilot lamp, or other low-current light in town, for that reason.

Title: Re: 6v to 12v conversion
Post by: Housewiz on 15.12. 2012 19:35
I have read somewhere the belt-driven dynamo conversion spins the dynamo gear a bit faster - would that help with low speeds in city driving?
Title: Re: 6v to 12v conversion
Post by: trevinoz on 15.12. 2012 19:37
Much better to rewind the generator for 12V operation.
Title: Re: 6v to 12v conversion
Post by: groily on 15.12. 2012 19:57
I've been running with DVR2s at 12v for years on 2 bikes, and since very recently on my A.
All the above is true, but I live in the back of beyond so the town thing isn't an issue for me. However, using in my case an SRM belt drive, the loads balance at 12v at just on an indicated 40mph in top (with an extra tooth on the gearbox sprocket). One bike, not the A, uses a finer-wound armature and field, the other 2 run on standard windings. The fine-wound dynamo obviously cuts in faster, but the heavier '6v' windings are capable of supporting loads up to 80-odd W and I have had no problems. As i say, I live in the boondocks where trickling around isn't necessary. I've tended to go for meaty batteries - meatier than strictly necessary probably - and am very happy with all three bikes in year-round quite heavy use. It's Horses for Courses really. Cheers, Bill
Title: Re: 6v to 12v conversion
Post by: Housewiz on 15.12. 2012 20:34
Sorry for so many of these rookie questions. 

What is a DVR2?

To "rewind" the generator, what is involved in that?  And who does it?  An electric motor shop?

Trying hard to come up to speed on these A10s so I don't have to ask tons of questions - so many bits of info to inhale and parts to sort out.  It's a very good thing I don't have plans on riding until next summer.  It will take me that long to sort out all this stuff.

Thanks,

Steve
Title: Re: 6v to 12v conversion
Post by: metalflake11 on 15.12. 2012 20:58
A DVR2 is a brand of regulator, they are very good. Which country are you in? If you are in the UK then I could make some suggestions.
Title: Re: 6v to 12v conversion
Post by: Housewiz on 15.12. 2012 21:03
Live in the good old USA - far away from the treasure trove of mechanics, shops, parts and other related A10 resources your lucky guys have in the UK.  Strange it's like that because BSA exported so many bikes here.  Also, I am just getting into the A10 scene.  Two Brit bike shops around but far too few parts, spares, etc.

Thanks,

Steve
Title: Re: 6v to 12v conversion
Post by: metalflake11 on 15.12. 2012 21:22
Sorry Steve I can't help you other than with advise. If the dynamo is working ok you can wire it 6V or 12V. The regulator S.R.M. sell is very good, as is the DVR2. They also sell a belt drive kit which increases the revolutions of the dynamo by 10%. This too is an improvement on standard in todays traffic chaos, when riding on sidelights is not really a sensible option. It does of course wear your dynamo out 10% quicker!
Title: Re: 6v to 12v conversion
Post by: Triton Thrasher on 15.12. 2012 22:00
Much better to rewind the generator for 12V operation.

Except, it's physically less robust then.
Title: Re: 6v to 12v conversion
Post by: warmshed on 15.12. 2012 22:27
The majority of people use a standard 6 volt generator without problem. The DVR2 (Dynamo Regulator mk2?) can be seen here http://www.dynamoregulators.com/dvr2.php

The SRM/DVL tooth belt dynamo conversion increases the relative speed of the dynamo by 10% and 20% respectively,   and therefore enables the dynamo to balance the load at lower engine revolutions.
I would not think the dynamo would wear out 10% (or 20%) quicker, the mag/dyno set up on many bikes has increased dynamo to engine speed (by 20%) and they don't suffer from increased wear.

The more modern electronic regulators do cut in much earlier than the older ones, unless you are doing a lot of sub 30mph riding you should not find it a problem even with the original chain drive.

If you envisage lots of very slow driving the use of a lower wattage bulb or bright pilot as suggested is, as suggested, worth considering. LED rear lights also help to reduce the load the dynamo has to supply.

All the  bikes I know with 12 volt regulator conversions use the standard 6 volt dynamo without problems and benefit with good lighting, don't forget that using 12volts on the thicker 6 volt wiring gives a reduced voltage loss adding to its efficiency too. I certainly would not go back to 6 volts.
Title: Re: 6v to 12v conversion
Post by: metalflake11 on 15.12. 2012 22:50
Surely, increasing the revolutions of the dynamo by 10 or 20% (whichever it is) for every mile travelled will result in higher wear and tear of the bearings and the brushes by a similar ammount?
Title: Re: 6v to 12v conversion
Post by: warmshed on 15.12. 2012 23:02
Surely, increasing the revolutions of the dynamo by 10 or 20% (whichever it is) for every mile travelled will result in higher wear and tear of the bearings and the brushes by a similar ammount?

Just because it turns quicker does not necessarily mean greater wear, as long as the dynamo is turning within the specified rating for the bearings. I am not sure of the speed rating of the bearings but I don't believe that the extra 20% will ve beyond the working speed of the bearings fitted, especially as not many rider run at a constant 6000+rpm

Brush wear is more related to the current its passing, at 12 volts for a similar load it will be half that of 6 volts so even with increased speed the wear should actually be less than standard 6 volt system..
Title: Re: 6v to 12v conversion
Post by: trevinoz on 16.12. 2012 02:28
TT,
      I disagree that a 12V wind is less robust.
I use 0.7mm wire for 12V, 0.8mm for 6V, in the armature.
For the field coil I use 0.6mm instead of 0.7mm.
Hardly a great difference.
The generator will deliver 80W easily, which should be enough for any A10, without over heating.
I don't like the practice of running a 6V generator at 12V mainly because the field coil is drawing around 4 Amps when the generator is working hard.
The coil is not designed for this and will tend to over heat not to mention the 2 amps which could be put to better use.
I have seen enough cooked field coils in my time and the generators were only running at 6V.
I have only had one of my 12V armatures fail in service, with thrown solder. This was found to be caused by a faulty regulator.
Luckily the conductors were not burnt at the commutator and a resolder and new regulator fixed the problem.

Trev.
Title: Re: 6v to 12v conversion
Post by: Triton Thrasher on 16.12. 2012 07:49
Good stuff Trev. Maybe some conversions aren't as good as yours.  Years ago, a guy on the phone at SRM was very reluctant to sell me a 12V dynamo, even though they had them advertised, because they weren't lasting long. I know that's hardly first hand experience.

I did many miles with a 6V dynamo at 12V. Probably lightly loaded most of the time, but did have 60W headlight and coil ignition for a while.
Title: Re: 6v to 12v conversion
Post by: BSA500 on 17.12. 2012 09:32
Hi,
I had my dynamo sorted by Andy at Priory Magneto's. Because I ride all year round in town and country he recommended the 12 volt wound. Before that the battery would flatten and the dynamo would overheat,so much so last time the armature expanded and split the bearing *eek*.
So now I run DVR2,12 wound dynamo and a 9ah lead acid(used the gel cells but they didn't like the flat/charged cycles so much :!).Andy also recommended I go back to chain drive as he feels the tightness the belts run at can be a little harsh on the dyno bearings. Not aproblem as the dynamo now cuts in at BSA designed speeds.
Title: Re: 6v to 12v conversion
Post by: metalflake11 on 17.12. 2012 17:04
Well you live and learn something new every day!....Thanks Warmshed.
Title: Re: 6v to 12v conversion
Post by: bikemadinspain on 17.12. 2012 18:33
Thanks to everybody who gave the great info on this post and especially to the chap who asked. I have been wondering about how the hell I was going to sort this problem for a while and now I have a better idea, cheers.

PS; Me and electrics, we get on like me and my first wife!!!!
Title: Re: 6v to 12v conversion
Post by: BSA500 on 02.12. 2013 20:28
Update... A year on and no issues bright lights all the time incl all last winter(except when it snowed)  *smile*
Title: Re: 6v to 12v conversion
Post by: terryk on 03.12. 2013 14:51
One thing I always do when wiring up a bike is run an earth wire from the headlight to the battery earth or frame earth. This is instead of trying to get a good earth thru the grease in the fork triple tree bearings. It does make a difference to the headlight brightness.

I've always just used 6V it's ok for me. If I had to get a dynamo completely overhauled I would probably go to 12V if I didnt have spare good 6V dynamos which I do have plenty of. I've just always kept the old 6V ones working.

A good battery is the key I think if its going flat easily ditch it and get a new one. If I ever get a flat battery for whatever reason I pull it out and charge it with a charger instead of trying to let the dyno on the bike charge it. Its just what I do but if its night time and you need to get home do whatever.

Rant over
Title: Re: 6v to 12v conversion
Post by: Greybeard on 03.12. 2013 17:31
One thing I always do when wiring up a bike is run an earth wire from the headlight to the battery earth or frame earth. This is instead of trying to get a good earth thru the grease in the fork triple tree bearings. It does make a difference to the headlight brightness.

I bought a new loom for my A10, (from Draganfly I think). I was pleased to see it included earth return wires so the frame is not part of the electrical circuits on my bike. The 6v lights seem pretty good to me, however  I know that headlight strength requirement is related to speed; I tend to ride at a suitable speed for the machines brakes and lights.
Title: Re: 6v to 12v conversion
Post by: 1959superocket on 04.12. 2013 18:33
Hello,
My bike has E3L 60 watt dynamo, SRM dynamo belt drive, DVL2 voltage regulator and 2 cyclon dry cell batteries in series.

The dynamo was restored to 6v standard for the thicker wire rather than the thinner wire for reasons stated by others and the regulator steps it up to 12volts.

The bike has SRM electronic ignition in the K2F magneto and I think this takes just 9 of the 60watts and the only other pull in daytime is for brake light so I have some charge going back into battery.

You need to add up all the wattages and even with the faster spinning dynamo if you up the ratio I think you might find the E3L will struggle.

You could use Paul Goffs low wattage LED lamps instead of the normal headlight tail and stoplight bulbs but if it was me I would look to use one of those replacement alternators rather than the E3L.
Regards
Stuart


 
Title: Re: 6v to 12v conversion
Post by: fido on 22.01. 2014 17:55
You might need some of this:

(http://img.photobucket.com/albums/v161/NVNLHOBDEN/th_1236983_448877161896614_101872915_n_zpsa5a11b27.jpg) (http://smg.photobucket.com/user/NVNLHOBDEN/media/1236983_448877161896614_101872915_n_zpsa5a11b27.jpg.html)
Title: Re: 6v to 12v conversion
Post by: muskrat on 23.01. 2014 09:09
Looks like you have used it all fido. *roll*
Cheers
Title: Re: 6v to 12v conversion
Post by: bsa-bill on 23.01. 2014 19:01
Some nice shots on your page Fido - got a good eye methinks