markjenn said:
If bikes "vary much more" than they should be more tolerant of charging voltages on a car bus, not less. Haven't checked the S10, but immediately after starting (especially if the battery is at all low), most bikes' bus voltage is 14.5+ to charge the battery. As are battery chargers, even trickle chargers. I'll still maintain that a car's and bike's systems are basically regulated to the same general bus voltages as they both are spec'ed to be 12V systems. We'll have to agree to disagree on this point. In any event, I do agree that there is seldom any need to start a car when doing a jump.
- Mark
Mark,
Most bikes don't vary voltage immediately after charging. They just aren't setup like this. Instead they have an AC stator that puts out differing voltage based on RPM. That source is then rectified and regulated by the regulator rectifier. Most bikes don't make peak charging at idle. The regulator/rectifier in most bikes (S10 included) is not "smart". It tries to make the best of its situation. It allows the voltage to go as high as it is designed to, and then kills the rest. Killing the rest is what strains the R/R.
Per the service manual, the S10 charges at 14V at 5k rpm.
Most car alternators charge at 14.5V, some spiking up to 15.3V.
The bike reg/rect setup is designed to work along with the normal loads of the motorcycle (headlight/fuel pump/etc).
What happens when a car is left running AND the bike starts and continues to run, is that the R/R must shed off ALL of the energy produced by the bike's onboard charging system since the car has its needs more than covered.
I agree with you, that it is UNLIKELY that simply JUMPING the bike with a running car will cause an issue.
BUT
Do NOT leave the car connected with the bike running.
You CAN safely leave the car running connected to the bike...IF the bike is NOT running.
ac