Andy
<<<snip>>>
I have a Pertronix electronic ignition inside the dizzy . . . is
it
polarity sensitive?
<<<snip>>>
YES!
<<<snip>>>
I suppose I could isolate my tachometer and keep it postitive
ground
to run the clock,
<<<snip>>>
Original TD tachs were mechanical. You'll need an electrical one
designed for the negative ground. I don't know if the MGB's are
the same diameter, but I think they're smaller.
I have halogen headlamps in my TD and am still using the original
19 amp generator.
55 watt halogens times 2 = 110 watts
6 watt sidelamps times 2 = 12 watts
6 watt tail lamps times 2 = 12 watts
2.2 watt panel lamps times 4 = 8.8 watts
6 watt number plate lamp = 6 watts
.5 watt fuel or highbeam lamp = 1 watt
---------
Total = 150 watts divided by 12 volts =
12.5 amps
12.5 amps plus the three amps my ammeter says for the fuel pump
and coil, when the key is turned on, is 15.5 amps. This is less
than the 17 or 19 amp output specified in the shop manual.
Additionally, the coil and fuel pump are intermittant use as are
the stop lamps.
(The voltage regulator is set at about 16 volts, and the lamps
run from the generator when the engine is running. So perhaps
the power consumption is less at about 10 amps. Am I right on
this O knowlegeable ones?)
So you can use the hologen headlamps without changing to an
alternator.
Here's another way of looking at it. Standard tungsten headlamps
are 36/36 watts. Add on the tungsten fog lamp at 48 watts. Thus
two 36's and one 48 equals 120 watts. The two halogen head lamps
are 110. So if you're not using a fog lamp, the original
generator will easily handle the load.
My ammeter doesn't show a discharge with the halogen headlamps on
and one 55 watt halogen fog or driving lamp on. The ignition
warning light would also come on with excessive current draw.
However, my warning light has been modified for other purposes.
I also know that I could run the standard tungsten headlamps with
the 55 watt halogen driving lamp with no problems. That was when
the ignition warning lamp still functioned as designed.
The generator was designed to operate ALL of the electrical
accessories, PLUS charge the battery. If the battery is
completely charged up, than all available current can be used to
run the lamps and wiper motor.
Blake
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