NIGHT DRIVING IN A CHUMMY

Our Chummy has a completely standard, original set up with 6v electrics, original CAV DEL dynamo with full and half charge and the original CF1 cut-out. The only extra electrical draw I have added are brake lights.  The car came with original 6v bulbs all round, which with the headlights on sent the ammeter off the scale past maximum discharge. They gave a very authentic, vintage look, but put a lot of strain on the system. The rear lights were about as bright as undernourished glow-worms.  I had got LED headlight bulbs from Ian Jury who runs Classic Dynamo & Regulator in Lincoln, for use in R47s on a Mulliner Sports Austin 7 that I played with. They worked very well, but this car had 12v electrics with dip and main beam function. With freshly re-silvered reflectors in the R47s this worked very well.  Ian Jury has developed a lot of new products since I bought his early version of LEDs for the Mulliner, which then relied on the original reflectors in the lights.
I bought his LED side light bulbs which are single filament and they went straight into the Chummy’s R47s and worked perfectly. I then explained to Ian that I wanted a single filament headlight bulb as the Chummy does not have dip and main beam, just headlights on and off. He said his twin filament Double Dipper Pro bulbs would be best and to make them single filament he would simply solder the two terminals together for me to make a single filament bulb.  They do not rely on the reflector in the R47s so the fact that mine are slightly yellow in colour due to age would not matter. They arrived in the post and I simply put them straight into the original single filament bulb holders in the headlights and turned them on.  I then explained that I wanted LEDs to fit into Lucas AT 201 rear lights to act as stop, tail and number plate lights, which again he makes specifically for this light unit. Again, I simply put these straight into the original bulb holders.
With the engine on tick over and the headlights on, the ammeter shows discharge of about 5 amps. When driving at approximately 40 mph the ammeter shows zero amps which means the dynamo is keeping up with what the coil is drawing to run the engine and what the LEDs are pulling.  I didn’t want the complication of having to change the wiring or charging set up of the car as I wanted to keep it original. All I wanted was to change the bulbs for modern equivalents which meant I could enjoy driving the car at night with lights that meant I could see where I was going and equally that meant modern car drivers could see me. This way I feel I have retained the originality without sacrificing the usability of the car.
Richard Wadman DA7C