12 volts from a 6volt dynamo

[marcus whatling]

Just been reading the Bibliography & lore Square Forum And a good read it is too .
Page 37 got me wondering if it was easy to get 12 volts from a 1953 MK2 6 volt Dynamo. The artical talks about a J.G Unit With its Schottky Barrier Diode (may as well read a flux capaciter to get me back to the future ). I wasn't sure if any of the solid state type Reg Rec units for sale that fit in to the old FADE unit were the same or if this was a special unit ? REF from Dave Lindsley 770118-20.
I am doing some work on the SQ4 and if !" Volts were available it might be a good idear. Didn't want to go for the 12v alternator conversion at the moment due to cost

[Keith.owen]

Hi,
My understanding is that with the correct regulator a 6V dynamo (60Watt version) will output up to 90Watt if operated at 12V. Clearly it was not designed for this so heat dissipation could be a problem if it is run at this higher output for long periods of time. This for the reason that the voltage applied to the field coil will be higher and thus so will the current flowing through it. This does not effect the armature because in actual fact if the voltage is doubled the current is halved to do the same amount of work (Watts of output) - In practise the dynamo voltage will just rise as engine speed increases until something goes pop (another job of the regulator is to limit this voltage rise).

The average engine speed may need to be higher in order to effectively charge the battery, but, I understand from discussion with one of the voltage regulator manufacturers that their product dumps voltage from the battery to the field coil at lower revs thus 'artificially elevating the dynamo output voltage). This of course only works as long as the dynamo is outputting more power than the battery is sinking into the field coils so, the net result is improved performance with a well designed electronic regulator over the conventional electromechanical types.

However, you can't ever get out more than you put in!!!

Keith

[Steven.Carter]

However, you can't ever get out more than you put in!!!

Keith

Well, I'm not sure about that. I'm sure more oil comes out of my primary then goes in

Now to be useful, I've converted to 12volts on two of my bikes and have had no problems, well so far.



Steve

[Bob.Murphy]

My VH is running 12 volts - using a "Classic Motorcycle Electrical Services (CMES) - Bristol" solid state regulator.

They don't appear to have a website, but can be contacted on 01454 323434.

This article may be useful, as are the other electrical fault-finding texts on the site.

http://matchlessclueless.com/electrical/lucas/12v-conversion/

I thought mine wasn't working as it never showed a charge - but it balances the headlight and the high-tech solid state battery doesn't appear to go flat!

CMES say in their fitting instructions . .

"For a 12 Volt system with a 60 Watt load, the speed required to to equalise the charge is around 2,300 to 2,500 rpm - compared to approximately 1,800 rpm with a 6 Volt system". That's using a Lucas E3L dynamo with both output wires ganged together.

I do like the look of the Alton alternator . . I'm thinking of putting one on the 1930 500 Panther I'm restoring as I don't have a dynamo for it at the moment. 2,500 rpm may be an issue though



Bob.

[Keith.owen]

Hi,
Yes I have also looked at the Alton but I considered it to be very pricey for a machine that will undergo only occasional night time use (my machines that is).

I bought a regulator from a company in Fareham and am happy with it.

The challenge is to, as far as possible, balance the load so that the battery receives a trickle charge when fully charged and the dynamo / alternator supplies current to the other devices that are in circuit (load i.e switched on).

Using LEDs as much as possible, so that only the headlight really consumes any power, a Lucas dynamo operating at either 6V or 12V should be easily capable of charging a battery and then maintaining it's charge provided the rider doesn't ride around continuously banging the horn.

John Nash wrote an article on LED lights that makes good and useful reading.

Keith

PS. Will the Panther pull a chair?

[Bob.Murphy]

PS. Will the Panther pull a chair?

Well, it could, but I'll be riding it as a solo.

My intention is to ride it to the Panther Owners' Club Swedish Rally one day - but it won't be in 2014 I'm afraid as there is far too much work to be done on it at the moment (and I have four other bikes to fettle).

It has a three speed Sturmey Archer gearbox with a hand change, it could be interesting .

Many, many years ago I "had a shot" on a couple of Panther outfits, one was a '120' (650cc) around an empty car park (remember them?) but the other was a disreputable 600cc heap of **** that I tried out on the road.

I decided that chairs were not for me, but at one time I did consider fitting one to my '57 VB and taking it to the Green Elephant Rally at the Nurburgring - life and a very expensive 4G restoration got in the way of that idea .

I'm intending to take the 'VH' to the AOMCC Italian Rally in 2014 (I haven't told SWMBO yet ).

Bob.

[jim.haydock]

I've been using the 6v to 12v electronic regulator from Alan Osborn at A O Services http://www.aoservices.co.uk/index.htm for about 8 years now on my 1946 350 Red Hunter with excellent results over many thousands of miles. The only issue I've had is when I've inadvertently flattened the battery as the unit needs some life in the battery to fire it up. I've also found Alan also very good to deal with whenever I've had to speak to him. Check out the Battery Status Monitors that he also sells, comprising small LED's which glow green, amber or red to indicate whether or not your system is charging or keeping up with demand. I've fitted one to my Ducati 916 and I'll also be fitting one to the Huntmaster Project in due course.

[david.anderson]

What I can say is that with a rebuilt 6v Lucas C35SD on my mk2 which was fitted with a 25 tooth engine sprocket and running a 35w quartz headlight (turned on) the ammeter would not balance until 45mph. Fitted with a 6ah battery (too small but all that I could buy in 6v) and travelling at city speeds of 30 or 35mph the battery drained rapidly and the bike would miss or stall due to a flat battery, unless run around in third gear. The system was totally inadequate if you wanted to run lights on. As the 12v reg conversion does not cut in until higher revs, even more care would have to be taken to avoid flattening the battery around town with lights on, although a large battery would help.
I built one of Bennets alternators base on the Cheval article. I now run a 26 tooth engine sprocket (lower engine revs) a 60w headlight, handlebar heaters and a seat heater and the bike is still charging on the plus side at 30mph. The 300w electrics are superb.
I run an Alton on one VH and am very happy with it. Again I run a 60w headlight and handle bar heaters and easily balance the ammeter at city speeds. I did not find the Alton pricey as I needed a generator and regulator. Any 2nd hand lucas would have been in need of a rewind which would have added to the cost. The Alton came with a reg and the price ended up less than I could have purchased and repaired a lucas set up.
I also run a 6v lucas fitted with an AOL 12v reg on another VH. Again I run a 60w headlight and handlebar heaters and just get by around town, although with a VH I do not have to worry about a flat battery or power for the ignition. the VH is of course running higher engine revs than the 4 at the same speed.
David

[Keith.owen]

Hi David,
What issue of Cheval is the 'Bennet's described in?

I paid about £80 for a new armature and £40 for the solid state regulator. I don't recall what the bearing etc cost me.

The Alton's are going or around the £360 mark. If I was doing any serious night time riding ( or winter riding to that matter) then yes, of course, a 300 Watt electric system would be in the order!!!

Keith

[Bob.Murphy]

Until I bought the 'VH' this year I'd forgotten just how underpowered old British bike electrical systems were .

My 2004 BMW R1150 GS Adventure has a 720 Watt 12V alternator - that's 60 Amps .

I'm seriously considering an Alton for the VH.

Bob.