Two Wheel Fix - View Single Post

JoshuaTree · 03-28-2009, 12:26 PM

12VDC IS 12VDC, but not all 12VDC systems are created or operate equally...

The anecdotal stories / experiences about frying bike electrics I would guess come from the nature of the output of car/truck alternators. They're much higher amp output, and they also have a slightly sloppier tolerance for charging voltage. When the sense lead from the car/truck senses the voltage drop due to the now connected dead motorcycle battery, it goes into high output (voltage) charge mode. If you then 'rev' the car/truck, you should get a nice big 60-140A 'push' from the alternator at whatever the maximum output of the alternator.

And how many of these "it blew up my bike" stories left out the detail that they probably connected the negative terminals first (i.e. "drain"?) then connected the positive terminals (i.e. "supply"?)? I was taught that the order for jumper cable attachment is always:

1) Positive terminal of discharged battery
2) Positive terminal of the charged battery
3) Chassis Ground of the discharged battery
4) Negative terminal of the charged battery

YMMV...

For reference:

03-28-2009, 12:26 PM	#16
JoshuaTree DILLIGAF? Join Date: Nov 2008 Location: Austin, Texas, USA, Earth, Sol, Western Spiral Arm, Milky Way Moto: 1993 K75SA Posts: 483	My $0.02 (Unadjusted for Fed Currency Inflation...) 12VDC IS 12VDC, but not all 12VDC systems are created or operate equally... The anecdotal stories / experiences about frying bike electrics I would guess come from the nature of the output of car/truck alternators. They're much higher amp output, and they also have a slightly sloppier tolerance for charging voltage. When the sense lead from the car/truck senses the voltage drop due to the now connected dead motorcycle battery, it goes into high output (voltage) charge mode. If you then 'rev' the car/truck, you should get a nice big 60-140A 'push' from the alternator at whatever the maximum output of the alternator. And how many of these "it blew up my bike" stories left out the detail that they probably connected the negative terminals first (i.e. "drain"?) then connected the positive terminals (i.e. "supply"?)? I was taught that the order for jumper cable attachment is always: 1) Positive terminal of discharged battery 2) Positive terminal of the charged battery 3) Chassis Ground of the discharged battery 4) Negative terminal of the charged battery YMMV... For reference: __________________ "Quis custodiet ipsos custodes?" "Learn to do the counter-intuitive things that may one day save your ass..." "... Love Much, Laugh Often..." - Amanda Kay Corso (January 18, 1980 - April 15, 2008)