LED Auxillary Lighting

I've been thinking about getting a set of these to mount on my crash bars but curious if I have enough amperage to run these on top of all the normal things. How many extra amps do these bikes have to play with and has anyone ever done this already?

 

I have a 9000 lumen VisionX LED auxiliary light affixed to the center of the windshield mounted on my 1981 Maxim 650. It is wired to the high-beam circuit so I can turn it off in urban areas, or flash it to get extra attention when required.

The headlight itself is an H4 halogen with a modulator (flasher) provided by Len Chacal. He also provided the LEDs for the instrument cluster and a modulator for the LED tail light. All four turn indicators are converted to LED, controlled by a relay also acquired from Len. The relay is necessary to bypass the automatic turn cancellation, which I disliked anyway since it would too often cancel prematurely when I did not accurately judge time and distance to the turn.

The lower demands of the LED turn and tail lamps provide a nice margin of power for the auxiliary light.

I also replaced every plug-in connector on the bike with permanent, heat-sealed and crimped butt connections. This avoid the loss of current to unwanted heat at the connection points, a phenomenon that increases over the years as the connectors corrode.

I moved the wiring from the headlight bucket to a separate junction box mounted on the fork cross brace. This was necessary to make space for the H4 lamp which extends to the very back of the bucket.

I stuffed a battery charger into the compartment originally meant to stow the security chain (a CTEK unit mummified in silicone tape) and I keep it connected between rides.

I have not experienced a single electrical incident since.

 

On mine I ran an extra tail light on the sissy bar and a pair of 20W driving lights. I didn't have any trouble.

When I sold it I ended up buying a new battery because the buyer kept having it go dead on his test rides. I think it was more an issue of him not getting the RPMs up than the battery itself.

I think you've got at least 40 watts to play with. That's a lot of LEDs.

 

Does anyone know how many extra amps you have on a stock system on the 650 maxim?

 

Not much - the alternator is only putting out 19 amps at full power, and the bike is using probably 12-15 of those most of the time (depending on your bike - # of bulbs, type, etc)
LED's are great because they take next-to no power to run, so in theory you could add tons of them with little load -- but beware of the ones designed for automotive use - they may have resistors installed so they can run at 12v, and if they do they're likely taking just as much power as a regular bulb.

 

Most LEDs operate under 3V, so almost all 12V applications will have a resistor. It's the load balancing devices for turn signal flashers that really jack up the current draw because they are in parallel.

lostboy2, you're not going to get a definitive answer because the output of the alternator varies by RPM. At idle it doesn't output enough to keep up with the standard load and will discharge the battery.

A variable in the system is the state of charge on a battery. Charging the battery will take some power, more if the battery is deeply discharged.

An XJ650 alternator in good condition seems to put out enough power to operate the motorcycle and recharge a good battery at 2,000RPM. The service manual doesn't say anything about output except 19 AMPS at 14 Volts (19X14=266 watts) at 5,000 RPM.

The service manual for my Venture shows the maximum output at 5,000 RPM. It also has a graph showing output vs. RPM. On the Venture the alternator output at 2Krpm is about 2/3 its peak output. Assuming the XJ alternator is similar the alternator will output 177 watts at 2K RPM (that's 12 2/3 amps at 14V). That's right in the range Altus came up with.

Assuming our estimate is correct you have 6 1/3 amp available at 5Krpm. So if you add that much you'll discharge the battery at anything below 5Krpm.

So, your excess capacity is between 0 (2Krpm) and 6 1/3 (5Krpm). Assuming 14V that's between 0 and 88 2/3 watts. Average it and you come up with 44 1/3 watt (3.17 AMPs at 14V). That's pretty close to the 40 watt answer I originally gave.

BTW, watts is the correct term to measure power output/consumption. AMPs in and of themselves are meaningless without the voltage. LEDs are rated in miliwatts (1,000ths of a watt).

 

Thanks for the great information Micarl. Has anyone ever added LED auxilliary driving lights to these bikes? If so, what did you use and have youo had any issues with them? Thanks again.

 

I put a homemade one from parts from ledsupply.com
.6A , brighter than the headlight

 

Do you have a part number of what you ordered?

 

Ledsupply.com
Led....7007-pw740-n
Driver....3023-d-n-700
Optic.....3up carclo optic , try a few their cheap
I made my housing but they have those too, take a look at the DIY projects

 

Thanks Polock. I will check out the site and see what they look like.