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Electrical requirements


Kurt Snyder

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Kurt Snyder

How much of the alternator output is used for the operation of the bike (f inj, abs etc) and how much is left for extras such as driving lights, electric clothing, etc? I run a 80/100 watt headlight and installed PIAA 910 lights with 85 watt bulbs. I was thinking about 110 watt bulbs for the PIAA's but was wondering if there is enough capacity to handle the load of the lights, grips and vest.

 

Thanks,

Kurt

R1100RSL

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doesn't the alternator put out something like 700-900 watts? all electrical requirements are supplied by the alternator while running. I would think the normal demands of the motorcycle and the lights you want to put on are met by the alternator. On my F650 GS, the alternator wasn't as strong so I could put on strong driving lights and still be able to idle very long.

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Joe Frickin' Friday
How much of the alternator output is used for the operation of the bike (f inj, abs etc) and how much is left for extras such as driving lights, electric clothing, etc? I run a 80/100 watt headlight and installed PIAA 910 lights with 85 watt bulbs. I was thinking about 110 watt bulbs for the PIAA's but was wondering if there is enough capacity to handle the load of the lights, grips and vest.

 

I've seen similar sized fuel pumps running with 80-90 watts. No idea what the rest of the stuff draws. Need numbers for:

 

-Motronic

-ABS (computer only; pumps don't draw power unless ABS actually kicks in, which ought to be pretty rare)

-ignition system

-fuel injectors

-O2 sensor heater (is this on all the time?)

 

Other stuff is pretty minor (HES, TPS, oil temp, RID, etc.).

 

Being as the Motronic and ABS computers have pretty poor cooling, I gotta believe they're pretty low power consumption. Just a SWAG, but I'd bet the total electrical power requirements for running the engine (and ABS) are no more than 150 watts.

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ShovelStrokeEd

I seem to remember the net electrical load of a stock bike being somewhere in the neighborhood of 320 ohms.

 

You can easily determine if your load is too high. Buy one of THESE and hook it up. If your voltage drops below 12.6 volts, you will have to cut back the load some. BTW, the alternator, per BMW, does not reach its full rated output till 4K RPM so you should take that into account.

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I seem to remember the net electrical load of a stock bike being somewhere in the neighborhood of 320 ohms.

 

 

I sure do hope you mean 320 watts because 320 ohms would not even be 1 watt of power used by the bike.

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ShovelStrokeEd

Whoops! Watts of course. I sometimes wonder how I manage to tie my shoes. Now I remember, slip-ons.

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You've got 50amps, or 700 watts. Start figuring out how many watts you're using:

 

Headlight/low beem = 55w

highbeam= 55w

Tail light=21w (I think)

Instrument lights, figure 5 lights at 2w

Fuel pump=10-12=(wild assed guess)

RID=have no idea, but negligible...2-3w maybe...

 

I wouldn't worry about anything else unless it runs full time.

 

I guess it would be easier to tell you that you waaaay OK running the bigger lights, no problem. I'd stay away from increased wattage in your main headlight due to heat.

 

Let 'er rip on 110w, but they won't last as long as 85w, and you probably will not see a great deal of difference. Make sure you've got an excellent gound wire for both lights. That makes a big difference in output.

 

Enjoy!

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How much of the alternator output is used for the operation of the bike (f inj, abs etc) and how much is left for extras such as driving lights, electric clothing, etc? I run a 80/100 watt headlight and installed PIAA 910 lights with 85 watt bulbs. I was thinking about 110 watt bulbs for the PIAA's but was wondering if there is enough capacity to handle the load of the lights, grips and vest.

 

Thanks,

Kurt

R1100RSL

 

HIDs draw only 2-3 watts with X2 the power of a high performance halogen/incandescent...Oh and the high watt bulb will produce lots of heat as well as burn out in 100 hours or so. If you really want more light and are concerned about cost, figure the cost of high watt lamps at 100 hours against the lifetime of an HID (3000 hours minimum). Good HIDs cost about $150.00 and never need replacement.

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You have had no problems with the 80/100 (re: plastic reflector) in stop & go traffic? Careful of the heat generation in the PIAAs (call them), they're real expensive as you know.

 

You still have room for electric vest, radar etc.

 

You might like to check with a dealer to find out if you actually have 700w. Older models have (I think) 400w, the police alternators has more for those models and they are available.

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Kurt Snyder

I have been using the 80/100 watt bulb for 57,000 miles without a problem. I have also had a headlight modulator running during that time. I finally installed relays after 40,000 miles. I just installed the third bulb at 55,000 miles as preventative maint. Two bulbs in 55000 miles is good in my book. I use NAPA bulbs. My alternator puts out 700 watts at 4000 rpm. Currently lighting has 100 w headlight, two 85 w PIAA's, tail light, plus Signalminder running lights.(estimate 50 w) That's about 320 watts just for lights. Throw in a vest and grips and it's over 400 watts. If the figure of 320 watts to run the bike is correct that I have a problem now without going to 110 watt PIAA's

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I run PIAA 910's with 110 watt bulbs in each on my R1150RT. I also use a Gerbings electric jacket and electric pants, plus the electric grips. The 910's get used at highway speeds, which can be 55 to 60 mph in high gear, a "lower" rpm. I've never had any problems with all this current draw, and I have over 50k on the clock.

 

I ride a lot and I ride at night a lot, including cold nights in spring and fall at night (electric clothing turned on high). If you have the 700 watt alternator, you won't have any problems with your 910's. They are great for spotting deer and seeing at night, when there is no oncoming traffic.

 

I set mine up with relays, so the handlebar switch switches the 910's on when I flip the switch to high. In addition, my "fogs" turn off when the 910's are fired up by the handlebar switch. The fogs turn back on (and the 910's turn off) when I lower the headlight to low with the handlebar switch.

 

The fogs draw 55 watts each. In my case, all the electric clothing, plus the 910's, and I didn't want the extra unnecessary draw of the fogs when I have the 910's fired up.

 

MikeS

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I've seen similar sized fuel pumps running with 80-90 watts. No idea what the rest of the stuff draws. Need numbers for:

 

-Motronic

-ABS (computer only; pumps don't draw power unless ABS actually kicks in, which ought to be pretty rare)

-ignition system

-fuel injectors

-O2 sensor heater (is this on all the time?)

- The fuel pump takes about 2-3 amps (about 25-40 Watts)

- ABS, I don't know

- Ignition averages a couple of amps (say, 25 Watts)

- Injectors are essentially zero, since they have a low average duty cycle

- Oxygen sensor heater is switched off when hot, as I understand it, but when on, probably uses only 20-30 watts.

 

Bob.

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