fb40dash5
Junior Member
OK, I searched and searched. If this has been covered before, let me know, I'm all about giving credit where it's due!
I've been looking at the different headlight mods and their pros and cons. The simplest way is to just run a jumper from the low beam of the left bulb to the empty low beam of the right bulb. Works, but draws extra power on high beam, and also probably shortens the life of your H4, burning both filaments when on high beam. So then we add an NC SPST relay to the mix, using the high beam wire to open the relay, and kill power to the low beam of the H4 when using the high beam. For all intents and purposes, this works, but you've gotten little benefit from mounting and wiring the relay- the headlights are still drawing full power through the headlight switch on the handlebar. The more elegant version is to just add the "missing" wire to the connector to power the right low beam- simple, it works, but again, you're still drawing all the power through the switch and small, meandering wires.
The closest I found to this idea was PrayHarder's mod, though the initial plan was a bit overcomplicated, and involved modding a bulb or the headlight to fit an H4 in the left for dual high beams as well.
Sorry for my dumpy MSPaint schematic. Pay no mind to the far right relay, I just doodled that in assuming I would add a relay for the horn while I'm at it, so I could upgrade the horn in the future.
Fused power from the battery runs to the first SPST relay, which is closed by the signal from the stock low beam wire. The output of this relay powers the left headlight, as well as input power for the SPDT relay. It could also be used to provide switched power to a power outlet or just about anything else, since the headlight shouldn't be drawing more than ~10A through that 30A relay. The normally closed contact of the second relay powers the low beam of the right headlight, but only when the left headlight is powered. When the high beams are switched on, the second relay switches the right low beam off, and the high beam on. You could also switch to a pair of H4s and run them both from this second relay, or even leave the H7 and do the same, though you would then only have one bulb on high beam rather than low beam!
This way, all 3 (or 4, if you switch the left bulb) filaments are drawing power "directly" from the battery, and you don't have both filaments of the H4 burning at once, as well as gaining a switched power source that's limited by the bike's charging system more than anything else. It could also be made totally plug-and-play and removable by using male and female H4 plugs- just plug the stock connectors in, plug the new connectors into the bulbs, and hook up the battery leads!
Note: I'm not claiming the concept as my own. Most of it (especially the plug-and-play idea) was inspired by the IPF and similar H4 relay harnesses for cages.
I've been looking at the different headlight mods and their pros and cons. The simplest way is to just run a jumper from the low beam of the left bulb to the empty low beam of the right bulb. Works, but draws extra power on high beam, and also probably shortens the life of your H4, burning both filaments when on high beam. So then we add an NC SPST relay to the mix, using the high beam wire to open the relay, and kill power to the low beam of the H4 when using the high beam. For all intents and purposes, this works, but you've gotten little benefit from mounting and wiring the relay- the headlights are still drawing full power through the headlight switch on the handlebar. The more elegant version is to just add the "missing" wire to the connector to power the right low beam- simple, it works, but again, you're still drawing all the power through the switch and small, meandering wires.
The closest I found to this idea was PrayHarder's mod, though the initial plan was a bit overcomplicated, and involved modding a bulb or the headlight to fit an H4 in the left for dual high beams as well.
Sorry for my dumpy MSPaint schematic. Pay no mind to the far right relay, I just doodled that in assuming I would add a relay for the horn while I'm at it, so I could upgrade the horn in the future.
Fused power from the battery runs to the first SPST relay, which is closed by the signal from the stock low beam wire. The output of this relay powers the left headlight, as well as input power for the SPDT relay. It could also be used to provide switched power to a power outlet or just about anything else, since the headlight shouldn't be drawing more than ~10A through that 30A relay. The normally closed contact of the second relay powers the low beam of the right headlight, but only when the left headlight is powered. When the high beams are switched on, the second relay switches the right low beam off, and the high beam on. You could also switch to a pair of H4s and run them both from this second relay, or even leave the H7 and do the same, though you would then only have one bulb on high beam rather than low beam!
This way, all 3 (or 4, if you switch the left bulb) filaments are drawing power "directly" from the battery, and you don't have both filaments of the H4 burning at once, as well as gaining a switched power source that's limited by the bike's charging system more than anything else. It could also be made totally plug-and-play and removable by using male and female H4 plugs- just plug the stock connectors in, plug the new connectors into the bulbs, and hook up the battery leads!
Note: I'm not claiming the concept as my own. Most of it (especially the plug-and-play idea) was inspired by the IPF and similar H4 relay harnesses for cages.
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p) I went ahead and bought the supplies for it today. Three relay blocks (one for the horn relay) that dovetail together, a pair of H4 bulb connectors, a SPDT Hella relay, and a cool SPST Hella relay with double 87 terminals- one to the H7 bulb, one to the SPDT relay, no splicing needed!
