Don Enderton wrote:
>
> I'm replacing the right low beam bulb on my 98 Accord EX V6 sedan for the
> first time, which gives rise to two questions:
>
> 1) The owner manual says to use a 51 watt HB4 bulb, and that's also stamped
> right on the plastic near the bulb on the car itself. But most of the HB4
> bulbs I see listed by auto parts dealers are rated at 55 watts, not 51
> watts. If I only replace one low beam bulb, will this cause a visible
> mismatch in the amount of light from each side? Does it make any difference
> whether it's 51 watts or 55 watts? If so, does anyone know the brand name
> and dealers for a 51 watt bulb?

There are several standards for rating automotive light bulbs. Some
require the power to be measured at 12.8 Volts, others at 12.0 Volts
(and I believe 13.2 Volts is used as well). HB4 / 9006 type bulbs are
rated 55 Watts at 12.8 Volt, and 51 Watts at 12.0 Volts. Same bulb just
measured at two different voltages.

And in case someone finds that the numbers do not jive with Ohm's law,
when you run the bulb at 12 Volts rather than 12.8 Volts, it will run a
tad cooler, and the resistance of the filament will be a little less.