My personal feeling is 55/60W H4 bulbs with the Hella conversion cases is OK with SPF stock wiring. This is a tremendous upgrade from the 2D1 sealed beams.
--However anything hotter (amp wise ,like an 80+w constant bulb) I would upgrade the headlamp wiring with a relay kit.
2 key items ;
I > You are using a Lucas repro headlight switch
If you go beyond 60W's you are now feeding way more amperage through the switch than intended by design.
II > The Wipac lamp bucket wiring inserts.
In the stock SPF headlamp assemblies (with the wiring colored as various blues) are sourced from WIPAC, a classic British light supplier. they come with a wiring insert for the socket and supporting it is a pretty tiny gauge of wire, like 22ga. This is a smaller ga. than the say 20ga SPF car wiring that feeds them from the headlamp switch.
-- both of which I was personally uncomfortable with running my Proposed Hella H4 80-130s on.
OK, here is the
AMPERAGE Math ;
A> (Normal Hella H4 55-60W) 55W bulb x 2 headlights = 110Watts.
Watts / Volts = AMPs. --- so 110/12= 9.16Amps@55W
B> (Hella 80W base 80-130W) 80W bulb x 2 headlights = 160Watts.
Watts / Volts = AMPs. --- so 160/12= 13.3A @80W
C> (Hella 130W high beam) 130W bulb x 2 headlights = 260Watts.
Watts / Volts = AMPs. --- so 260/12= 21.6A @130W ( High Beam )
So in this case ; " B" This crossed my internal rule of no electrical circuit loaded more than 50% during normal use.
Wire Gauges and ratings ; -- and when I looked at the 22 ga. wiring in the buckets and consulted my handy ga/amps chart I found the following
22ga. rated to 7A.
20ga. rated to 9A.
18ga rated to 16A.
16ga. rated to 22A.
so 18ga would be fine. --
so I upgraded the headlamp harness - using the painless kit.
--- and now my headlamp switch is just in control of the relay circuit and not the ...
wait for it; " amperage of the lamperage".
--and I have been a happy (well lit) camper ever since.
Steve
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