ltljohn Posted October 24, 2008 Share Posted October 24, 2008 Hi All, I have an electrical question. Most everyone adds farkles to their bikes, most of which are electrical in nature. What I am looking for is the maximum safe additional load that can be placed on the electrical system without overloading it. This will vary from bike to bike but I am concerned with the 2002 R1150 RT. Alternator Output = XX Amps Standard load of bike i.e.; ignition system, lights, heated grips etc = YY amps This leaves me with ZZ amps to spare for farkles. Does anyone know what XX, YY and ZZ might be?? If this has been addressed please point me to the thread as my search skills are in need of polishing. TIA Link to comment
OoPEZoO Posted October 24, 2008 Share Posted October 24, 2008 Planning on adding an expresso maker? Link to comment
Joe Frickin' Friday Posted October 24, 2008 Share Posted October 24, 2008 Manual for R1100RT says the alternator puts out 700 watts. Fuel pumps are typically around 100 watts. Engine computer/plugs/injectors, figure another 100 watts. Standard headlight is, I think, around 60 watts. Grips ain't much, like 10 watts each. Servo brakes will draw plenty when in use, but that's a short-term draw, gone as soon as you're off the brakes. You're left with around 400 watts for accessories. Divide by ~13 volts to get about 30 amps; that's what you've got available. If you use all of that, you can't idle indefinitely; you'll draw down the battery, since the alternator can't put out 700 watts at that low RPM. Link to comment
ltljohn Posted October 24, 2008 Author Share Posted October 24, 2008 Planning on adding an expresso maker? I can use copper pipes around the exhaust to make expresso I was thinking of a microwave and fridge. Link to comment
bmweerman Posted October 25, 2008 Share Posted October 25, 2008 Planning on adding an expresso maker? How about a laser sighted crossbow that plays the William Tell Overture when in the firing position!? Link to comment
OoPEZoO Posted October 25, 2008 Share Posted October 25, 2008 Planning on adding an expresso maker? How about a laser sighted crossbow that plays the William Tell Overture when in the firing position!? I might have to look into that one.......its certainly intriguing. Link to comment
ltljohn Posted October 25, 2008 Author Share Posted October 25, 2008 Planning on adding an expresso maker? How about a laser sighted crossbow that plays the William Tell Overture when in the firing position!? Great idea, I could use it to shoot the cellphones out of cagers hands. Link to comment
bmweerman Posted October 25, 2008 Share Posted October 25, 2008 Planning on adding an expresso maker? How about a laser sighted crossbow that plays the William Tell Overture when in the firing position!? Great idea, I could use it to shoot the cellphones out of cagers hands. Now THERE'S an idea! Link to comment
boatzo Posted October 25, 2008 Share Posted October 25, 2008 Planning on adding an expresso maker? How about a laser sighted crossbow that plays the William Tell Overture when in the firing position!? Great idea, I could use it to shoot the cellphones out of cagers hands. Best one I have heard yet. Amen !!! Link to comment
270 Posted October 26, 2008 Share Posted October 26, 2008 One of the advantages of BMW's is the high output of the alternator compared to others on the market. Mitch is pretty close on what's available. Assuming you have a stock headlight, your hi-beam is 60w. If you run the fogs, they are 35w each, so that's another 70 for 130w of forward looking light. You also have a tail light which is (I think) 15w. If you're talking about farkles such as GPS/XM radio, map light...things of that nature, they just don't draw much if anyting really. You're looking at maybe 5w. Heated vest/liner, pants are going to be around 140w total... HTH...Also, if you're converting amps to watts, figure on alternator output at 14-14.1 watts while moving. Amps x volts will give you watts. Have fun!!! Link to comment
bmwmick Posted October 26, 2008 Share Posted October 26, 2008 HTH...Also, if you're converting amps to watts, figure on alternator output at 14Voltswhile moving. Amps x volts will give you watts. Our alternators are capable of putting out 10Amps at anything over 1,000 alternator RPM which I think happens about 700 engine RPM since it's a 1:1.5 drive ratio. I added the bold stuff. Mick Link to comment
11101110 Posted October 26, 2008 Share Posted October 26, 2008 I remember seeing something about the alternator's rated output requiring an engine RPM of 4000. I have been checking the documentation I have but have not found the spec that says that. Anyone? Link to comment
Stan Walker Posted October 26, 2008 Share Posted October 26, 2008 Can't speak for the RTP. The standard R1150RT spec can be found in the Engine Electrics section of the BMW service manual (page 12.3 in mine). 50 amps at 4000 engine rpm, 50 amps x 14 volts = 700 watts. 18 amps at 1000 engine rpm, 18 amps x 14 volts = 252 watts. Stan Link to comment
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