Battery or earthing problem?

[Hubie]

Not to worry chums,

I have begun the 12 volt conversion, just need globes.  Put a 12v battery on with a globe in the stop lamp, all works fine, the ammeter runs so that means that the reg was not getting enough power to tell the dyno to charge.

Cheers

Dave.

[trevinoz]

It seems to be a problem with some of the electronic regulators that they need a charged battery to allow them to start working.
It's not an issue with the DVR2 as I have found.
       Trev.

[Hubie]

G'day Trev,

All is working fine now, have a 12 volt flasher unit in the bike as well now as I have indicators.  I can tell the charging system is working fine as the ammeter moves depending on revs and the indicators flash faster above idle so I know the volts are going in there.  I just need a 12 volt headlamp globe which is the BPF style, although a mate has stacks of sealed beams at his place so I can convert that part of it for nothing.  BPF globes are not cheap!!

Cheers,

Dave.

[Hubie]

Still sorting my system out.  Did two night rides of about 6 miles and lights went right down.  I have a v reg iia on the bike and have read that it needs at least a 5 amp hour battery to work properly and prevent overcharging and I have a 4 amp hour battery in it.  My needle on the ammeter sits in the negative unless the revs are going well above idle.  I am wondering if the amp hour figure will make a difference or is it that my dynamo is simply not spinning fast enough.  If so,  is there a way I can speed it up?  Smaller sprocket on the engine side perhaps?

If it is all too much trouble, I am going to go back to 6 volt.  Will just need to replace the reg and globes and fit a 6 volt battery.  I would also be grateful if someone can measure their 6 volt battery and post it so I can find a suitable 6 or 12 volt replacement.

Cheers

Hubie.

[muskrat]

G'day Hubie,
                    sounds like there is still something wrong with your system, and I'm leaning towards your dynamo. Revs do need to be up a bit for it to charge, say about 30mph in top. I have a vreg2 on the '51 A7 and just fitted a new amp meter, it shows +4 with no lights and +2 with everything on. I have also fitted a belt drive that ups the speed by 5% from John at Lytedrive down there. I have an SRM kit on the cafe that ups it by 10% and starts charging just above idle ( just a light, no meter).
The vreg can be used for 6 volt as well. I think you just cut the looped wire, or is it join the cut wire. But thinking of that, is yours set for 6 or 12 volt ?? I will dig out my instructions for the vreg in the morning.
Cheers

[Hubie]

The system is set up for 12 volt.  Dynamo was rebuilt and works very well.  Maybe there is something wrong with the reg.  It is a vregII.  Still not sure what is going on.

[bsa-bill]

Can I suggest you take the battery of the bike and charge it up with a charger, then test it with a meter and see if it holds it's charge.
I have spent the last three weeks of and on trying to sort out a brand new battery, suspected the charger, suspected the acid, suspected a short/leak on the bike, I changed all these and came to the conclusion that the brand new (Chinese) battery is duff.
The battery would charge up but holding a meter on it would show a slow reduction of voltage, about .1 of a volt a minute ( this without load)

[muskrat]

G'day Hubie,
                     I can't find my notes on the vreg, but it's the little green wire loop that should be cut to go 12 volt. Here is the vreg page, have a look and re-check all yours. http://www.nanocontrols.co.uk/auto/v-reg2.htm
 Bill, a friend once told me a charged battery will loose about 1% a day = 0.12 volts. 0.1 per minute is way too much. New parts don't mean much anymore.
Cheers

[Hubie]

I am going to source a new reg just to see if it is the reg that is suspect.  I know that the dynamo is fine but on reading the notes on the vreg 2 it does say that it needs a good 5 amp hour battery to work properly and the one I have in it is 4.  If all else fails, I will get a new 6 volt batter and reg and put all the 6 volt globes back in.

I have also re fitted the standard 21 tooth engine sprocket to see if that helps.  My other solution was to try and find a smaller size sprocket for the dynamo chain (the engine one of course).  The standard is 27 teeth.   Does anyone know where I might find a smaller one?

[trevinoz]

Dave,
             The standard set-up is fine, it should work well as it did from 1949!
A smaller engine sprocket will run your dynamo slower!
You should find with the 21 tooth engine sprocket that your bike will pull away from 20 MPH in top  and keep accelerating into the 80s or 90s. Don't worry about the revs, they won't hurt your engine.
Trev.

[Hubie]

Thanks Trev,

The rev's wont hurt but it sure does vibrate!

[trevinoz]

Probably needs balancing!
                                       Trev.

[muskrat]

G'day again Hubie,
                             If you do a bit of night riding I would stick with 12 volt. I have never heard of different size sprockets for the dynamo and as Trev said the std setup is fine. I have a Vreg on the "51 and a DVR2 on the cafe and can't fault either.
Cheers

[Hubie]

I have a feeling the generator before it died might have overloaded the reg or damaged it in some way.  I will be testing to find out.  I will have decent 6 volt lighting considering i have low wattage but halogen headlight beam.  It is brighter than the 12 volt globe that i have in it right now.

Cheers

Hubie.

[muskrat]

Yep, when my dynamo spat the dummy it took the reg with it. I rebuilt the dynamo and seeing charge thought all was good. But what happened was the reg overcharged and cooked batteries.
Cheers