Regarding your fog lamp mod, here's some more information.
| 350 W System Design
Basis |
| Load |
Watts |
Amps |
| Low Beam OR High Beam |
55.0 |
4.6 |
| Sidelight |
5.0 |
0.4 |
| Tail Light + Brake Lights on |
21.0 |
1.8 |
| Turn signal lights |
10.0 |
0.8 |
| Number plate light |
5.0 |
0.4 |
| Instrument cluster bulb |
2.0 |
0.2 |
| Warning light bulb off (1.2 watts) |
0.0 |
0.0 |
| Fuel Pump (clean filter) |
60.0 |
5.0 |
| Horn |
60.0 |
5.0 |
| Cooling Fan |
60.0 |
5.0 |
| Electronic Ignition |
48.0 |
4.0 |
| Computer |
24.0 |
2.0 |
| Subtotal: |
350.0 |
29.2 |
| |
|
|
| Available for battery
charging |
0.0 |
0.0 |
| |
|
|
| Total: |
350.0 |
29.2 |
Normal Operating Conditions
The design conditions above are conservative, so here's a more common
operating condition with say two headlights operating simultaneously, no
horn or directional lights, cooling fan on. Even so, the early systems are
marginal.
| 350 W System Design
Basis Normal Operation with Two Headlights
On Design Mod |
| Load |
Watts |
Amps |
| Low Beam |
55.0 |
4.6 |
| High Beam |
55.0 |
4.6 |
| Sidelight |
5.0 |
0.4 |
| Tail Light + Brake Lights on |
21.0 |
1.8 |
| Turn signal lights |
0.0 |
0.0 |
| Number plate light |
5.0 |
0.4 |
| Instrument cluster bulb |
2.0 |
0.2 |
| Warning light bulb off (1.2 watts) |
0.0 |
0.0 |
| Fuel Pump (clean filter) |
60.0 |
5.0 |
| Horn |
0.0 |
0.0 |
| Cooling Fan |
60.0 |
5.0 |
| Electronic Ignition |
48.0 |
4.0 |
| Computer |
24.0 |
2.0 |
| Subtotal: |
335.0 |
27.9 |
| |
|
|
| Available for battery
charging |
15.0 |
1.3 |
| |
|
|
| Total: |
350.0 |
29.2 |
Fuel Pump Overload
Ducati superbikes use a high pressure fuel pump powered by a DC motor in
it's fuel injection system, so the fuel pump runs more often and draws more
current. One characteristic of DC motors is that if the system voltage
drops, the motor duty cycle will pull more current. So, if the fuel pump is
drawing close to 3 amps at normal operating voltage and the voltage drops
due to a second headlight, it will draw more current from the regulator
and/or blow the fuse. Further, a dirty/clogged fuel filter causes the fuel
pump motor to draw much more current from the regulator as the load on the
pump motor increases. Ducati incorporates an in-line fuel filter inside the
gas tank that requires regular replacement. A pump with a clean fuel filter
will draw about 2 amps, but this figure can rise to 10 amps with a dirty
filter. Clogged fuel filters are a prime contributor to regulator failures.
Regulator Relocation
Even 500 watt systems have marginal regulator/rectifiers. The reason why
they fail is simple overheating. Heat is the enemy of electrical components
and it's simply too hot inside the superbike fairing to cool them. Move it
to a location outside of the fairing and into the air stream. Extend the
wiring and mounted it on the underside of the license plate holder facing
the rear tire where it's hardly noticeable. The regulator still gets really
hot while stopped, so it's no wonder that they fail when mounted inside the
fairing. If it's any consolation, Honda's do the same thing.
Hope this helps,
Larry Kelly
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