Battery charging

I had a problem with my 650's charging some years ago, with the Ammeter (Lights off) taking a left turn at less than 50 mph in top.

I decided not to trust the Ammeter and bought the Paul Goff charge warning light and the results were the same. (Light went out above 50 mph in top with no lights on. Forget about night riding.

Turned out the air gap between rotor and stator was too big. I fitted the correct Lucas rotor and all was well. And now I have double proof of the charging situation.

As for the A reg, I have just fitted one to my Dommie racer but not yet wired it into the system so I can't comment on that.

Have a Areg 1 plus the BSM from Paul on a BSA B40WD. To my surprise charges with lights on at moderate revs. Also fairly easy to start without battery with a 2MC replacement. It must have have a good alternator.

Running but not connected yet the reason for me having an Areg1 in my Dommie racer is that I have a battery, alternator and a mag.Therefore it needed something like a zenner to take away the excess charge. I'm told that the Areg1 will take care of this and not fry the battery....We'll see.

Seems to me that Anthony's bike is not charging anything like enough. But that is stating the obvious. 

We are the back up for all three of these products.                                                                             With regard to large air-gap on the alternator, this I expect would have been due to fitting a 70mm rotor within the later stator. (74mm).

Warning-the original Warning light Assimilater was a 'tin can' underneath the petrol tank, this detected alternator output then switched the RED Warning lamp OFF (by disconecting and earth to the lamp). Having an Earth inside this device which very easily went faulty could/would often take an alternator wire to Earth. ON the original rectifier/Zener charging system this caused a low output (ie half of the rectifier was shorted) but no long term damage. With the modern rectifier/regulator this 'short' to earth of an alternator wire will actually cause permanent damage to the REG/RECT. Therefore it is recommended that the original 'tin can' Assimilater is not used.

Neil W By the way if you have a battery, alternator and a mag you do NOT use a zener. (although Zeners no longer available) As the output from an RM21 can easily push the zener over its 100W limit without coil ignition.

Hi Al,

Glad you responded to this to add an expert contribution.

No Zener on my Dommie racer project, it was the AReg1 that was recommended to deal with excess charge. Yet to be tested.....

I now have 4 Wassel 70 mm rotors, a lesson learned but the first thing Anthony should check.