Important info about headlights & "relays"
Light output and voltage.
Typically on a stock motorcycle the current powering the headlight,
auxiliary lights, horn, and accessories flows through many undersized
wires and small connections. The result is power loss or voltage drop
before reaching the intended device. The headlight is dimmer due to
the full battery voltage not reaching it. This voltage drop can be 1-2
volts on new or like new bikes. This light output loss can be
Why use a solid-state
"relay" to control your headlight? A solid-state relay
is a very low powered remote controlled switch. It allows the high
current to pass through it from the battery directly to the headlight
with negligible voltage drop about 0.1 volt. The current required to
remotely control a solid-state relay is about 0.00003 amps while a
power hungry mechanical relay requires about 0.3 amps or 10,000 times
greater current than a solid-state relay. A solid-state relay has
lighting fast switching and it does not degrade from electrical arcing
or mechanical wear - no clicking sounds.
Switchgear may last forever.
Your bike's switchgear now supplies milliamps or less to control the
solid-state relays instead of the many amps to the headlight before.
Switchgear is expensive to replace.
Increased safety. Solid-state
relays deliver near full battery voltage to the headlight giving
greater light output. You're more visible to others and you can better
Headlight heat problems. High wattage bulbs can significantly increase safety and
require special use care to avoid damaging bike parts. Extreme heat
can build up in the headlight housing damaging parts so adequate
ventilation is important. Also, the bike's stock wiring will conduct
more current heating up trying to supply the required power to the
headlight without a solid-state "relay" installed.