Help needed - CBR 600 wont start
in [Tech]
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From: No Spam on 16 May 2010 15:35 totallydeadmailbox(a)yahoo.co.uk (The Older Gentleman) wrote in news:1jilpqe.9zjpppn7ookyN%totallydeadmailbox(a)yahoo.co.uk: > No Spam <nospam(a)dont.bother.gov> wrote: > >> "." <an.gleann.mor(a)gmail.com> wrote in >> news:a1a87efb-06b2-4801-9540-0135e7e928c8(a)11g2000prw.googlegroups.c >> om: >> >> > >> > ...the point I was trying to make is that the >> > motorcycle's alternator would try to *charge* the partly >> > discharged car battery *and* the discharged motorcycle battery, >> > and that current would be too much for the alternator windings >> > and the RR diodes to handle. >> > >> >> The current the alternator can produce is limited by the internal >> resistance of the alternator windings, not the internal resistance >> of the battery. Any motorcycle starting battery can draw far more >> charging current than the motorcycle can produce. In fact, a >> motorcycle starting battery can draw more charging current than >> most car alternators can produce. Regardless of whether the >> motorcycle battery is rated for a lowly 150 amps of starting >> current or 450 amps, it's still more than the 90 to 120 amps a car >> alternator is limited to. >> > > So he's talking bollocks, is he? > > > Yes, but so was I... I tried to cancel that reply I made, simply because it was coming at the explanation from a completely irrelevant direction. The current is limited by the strength of the magnetic field, not the wiring resistance. According to my newsreader, I sucessfully canceled the post, but you obviously read it before It got canceled. Sorry, Joe
From: No Spam on 16 May 2010 16:09 "TigerJ" <tspill(a)talk21.com> wrote in news:pbqdnY5HGLpMSHPWnZ2dnUVZ8k6dnZ2d(a)bt.com: > > Also, can I jump start a bike from a car battery - just to be 100% > sure it isn't the battery. But I am fairly sure it isnt the > problem. > Yes, you can. Problems can arise when people jump start a motorcycle from a whole car, rather than an isolated car battery. If the car engine is running, the car voltage regulator is sensing the state of charge on the car battery. The state of charge of the motorcycle battery, at the far end of the jumper cables and through what may be poor connections, has little or no affect on the car's voltage regulator. If the car was just started, it's voltage regulator will be passing 15 Volts of charging current, to bring the car battery back up to full charge. If your problem stems from something other than a weak battery, your already charged battery could be heavily boiled and ruined in as little as 30 seconds. As long as the car engine is not running, this isn't a problem. regards, Joe
From: . on 16 May 2010 16:25 On May 16, 12:35 pm, No Spam <nos...(a)dont.bother.gov> wrote: > Yes, but so was I... > > I tried to cancel that reply I made, simply because it was coming at > the explanation from a completely irrelevant direction. The current is > limited by the strength of the magnetic field, not the wiring > resistance. According to my newsreader, I sucessfully canceled the > post, but you obviously read it before It got canceled. I know more than just a tiny bit about this subject, since my Uncle Sam sent me to aircraft and missile electrical repairman school... Actually, three main factors come into play when determing the current output of a permanent magnet alternator. They are: 1. Flux density of the magnetic field; 2. Number of turns of the wire wound around the iron core; 3. Frequency of the AC current induced by the magnetic field crossing the windings. The total length of wire affects the pure resistance of the wire, which engineers call "copper loss". The number of turns of wire and their spacing affects the inductance of the coils. The rate at which the magnetic field cuts the copper windings increases the inductive reactance of the alternator coils, current decreasing as frequency increases. True motorcycle racing story: Some friends wanted to decrease the width of a Suzuki GT750 motor so they could lean their endurance racer further over to the right. I suggested replacing the excited field alternator with a permanent magnet alternator from a dirt bike, so that's what they did. I told these guys (one of them was a *degreed* EE!) about the three factors mentioned above. The more practical-minded member of the ad hoc design commitee undertood that flux density was fixed if we used the permanent magnet rotor that we had, and that frequency was determined by engine RPM and would always vary. So he decided to wind as many turns of copper wire onto the cores as possible, stating that he would remove turns of wire as necessary to reduce voltage... Unfortunately, the alien PM alternator wouldn't produce sufficient current to charge the battery and run the Chrysler Multifire ignition system that the degreed EE had cobbled up. The Multifire unit needed 30 amps at low RPM and the current draw decreased as engine RPM increased... We were only getting about 3~4 amps out of the PM alternator... In order to double the current, we decided to install a second three phase full wave rectifier bridge in parallel with the first rectifier bridge... So we had enough current to keep the battery charged during the race. Unfortunately, too much enthusiasm and too many "engineers" involved in the project caused the engine to seize during qualifying...
From: The Older Gentleman on 16 May 2010 17:09 No Spam <nospam(a)dont.bother.gov> wrote: > If the car was just started, it's voltage regulator will be passing 15 > Volts of charging current, to bring the car battery back up to full > charge. If your problem stems from something other than a weak > battery, your already charged battery could be heavily boiled and > ruined in as little as 30 seconds. Bikes charge at around 13.5v, according to my mutlimeter. > > As long as the car engine is not running, this isn't a problem. Whch is how I always do it. -- BMW K1100LT Ducati 750SS Honda CB400F Triumph Street Triple Suzuki TS250ER GN250 Damn, back to six bikes! Try Googling before asking a damn silly question. chateau dot murray at idnet dot com
From: paul c on 16 May 2010 17:38
No Spam wrote: > "TigerJ" <tspill(a)talk21.com> wrote in > news:pbqdnY5HGLpMSHPWnZ2dnUVZ8k6dnZ2d(a)bt.com: > >> Also, can I jump start a bike from a car battery - just to be 100% >> sure it isn't the battery. But I am fairly sure it isnt the >> problem. >> > > Yes, you can. > > Problems can arise when people jump start a motorcycle from a whole > car, rather than an isolated car battery. If the car engine is > running, the car voltage regulator is sensing the state of charge on > the car battery. The state of charge of the motorcycle battery, at the > far end of the jumper cables and through what may be poor connections, > has little or no affect on the car's voltage regulator. > > If the car was just started, it's voltage regulator will be passing 15 > Volts of charging current, to bring the car battery back up to full > charge. If your problem stems from something other than a weak > battery, your already charged battery could be heavily boiled and > ruined in as little as 30 seconds. > > As long as the car engine is not running, this isn't a problem. > > regards, > Joe Nice posts, thanks. |