Anyone know how many watts our tail light/brake light pulls?

I'm considering adding a pair of running lights to the rear end, and dont want to add power drain. I figured if I went with a good quality LED brake light, and 2 small running lights....it would work OK so long as the new configuration pulls about the same power as the original incandescent brake light bulb.

Any help would be, as always, greatly appreciated.

Varies a bit by manufacturer but an 1157 bulb is around 25 watts for the bright(brake) filament and around 8 watts for the dim(taillight) filament.

Nice, I thought the bulbs would be higher priced

Well.....you are actually only reducing the 8 watt running light down to a 1 watt running light....and saving 7 watts.

The brake light portion of the bulb will be reducing the load from 24 watts down to 3 watts - but honestly how much of your ride is the brake light on........1% of your total ride time?  Same thing for the turn signals.....they are very little of the total ride time.  If your could find a clear or amber 1157 bulb to put in the front turn signals/running lamps you could save some energy....both front running lights are using 8 watts each.

Boogie_with_Stu wrote on 06/20/15 at 15:26:23:


I'm planning the exact same thing you're doing.  Are you at all concerned about heat with the rectifier?  The seat seems to have an molded airflow channel specifically for the rectifier to dissipate heat from the stock location.  

Also, when my rectifier recently went bad it produced an enormous amount of heat and after closer inspection I noticed that it had completely melted some nylon strings from my bags that were tucked under the seat.  If your rectifier goes out and it's sitting on, or close to other wiring I think it could possibly melt the casings.  

I removed my saddlebag yoke and replaced with two straps to avoid moving the regulator/rectifier.  I would really like to put the yoke back on.  Is moving the r/r forward safe?  If it is then I sure would like to see a pic of your relocation.

The charge system output is only slightly less than the bike uses, leaving only a few watts to be dumped, in the form of heat.
Decreasing the amount USED increases the amount that the RR has to dump.

I'm planning the exact same thing you're doing.  Are you at all concerned about heat with the rectifier?  The seat seems to have an molded airflow channel specifically for the rectifier to dissipate heat from the stock location.  

Also, when my rectifier recently went bad it produced an enormous amount of heat and after closer inspection I noticed that it had completely melted some nylon strings from my bags that were tucked under the seat.  If your rectifier goes out and it's sitting on, or close to other wiring I think it could possibly melt the casings.  

I removed my saddlebag yoke and replaced with two straps to avoid moving the regulator/rectifier.  I would really like to put the yoke back on.  Is moving the r/r forward safe?  If it is then I sure would like to see a pic of your relocation.

chzeckmate...I'm an electronic engineer by trade but I have forgotten anything I learned about closed 12 volt systems. The principles however, remain the same: Power (watts) is equal to the Amperage X the Voltage of the circuit. Even without knowing the exact resistance of the entire circuit, or the wattage rating of the rectifier/regulator...we can still come up with some nominal values.

I find it disturbing that your old Rectifier go so hot that it melted plastic. Normally a unit like that will fail OPEN. It is possible in your case, the alternator output (roughly 100 volts I think) was allowed to go straight to ground through the damaged rectifier/regulator. That would certainly turn the heat sink into a heater in a hurry. Not good.

The area just behind the air intake manifold does indeed have a lot of crap in the way. That is the area where all of the bikes wiring seems to meet up. Moving all of those wires and plugs/connectors out of the way isnt really possible. After reading your story, I started looking for alternative locations.

I have read somewhere that some Savage owners have relocated the R/R to the airbox. They bolt it to the plastic door/cover that covers the filter. Although I have a photo of a regulator set up like that, I have no clue how they did it. MY R/R is way to big and doesnt even fit inside that little plastic cover. The footprint is too large and the height of it makes it stick out close to an inch. Maybe I have an aftermarket R/R? Also, just stuffing the unit into the airbox in front of the air filter doesnt sound like a very good idea.

If I leave it where it is...bolted to the fender right behind the air intake, I suppose I could wrap all of the wiring that is nearby with heat resistant Fiberglas tape. It is rated at over 900 degrees F.

Another possible location would be to bolt it to the front side of the chrome battery box(under the carb). It actually doesnt look too bad in that location, although it does cover up a bit of the chrome. Of course, getting rid of the airbox altogether and going with a straight RYCA cone filter would free up tons of room....but I am not ready to go that route yet.

I'll update this as the week goes on...I'll be working on the bike all week. Anything that looks promising, I'll post pics.

I thought I'd revisit this just in case you're still working on your project or if anyone wants the info.  This is from the LS650 manual