charging battery

[avc8130]

The whole premise of this is that you believe a car's electrical system is regulated to a much higher voltage than a bike's. I simply don't believe this is true. As I said , agree to disagree.

- Mark

Sort of, but not quite.

Stolen from a VERY smart man on SV650/Triumph forums:

"It's not the current from the auto that's the problem, it's the voltage.
And it's not even that the voltage is detrimental to the main electrical system of the bike (even the ECM or igniter) - it's the R/R that suffers the consequences.
The output voltage from the running cage's alternator is going to be higher than the bike's R/R typical threshold, which means that in an effort to try to contol the output, the bike's 'dumb' R/R will shunt 100% of it's generated current from its stator once the engine starts.
So the cage doesn't actually kill it, it kills itself.
There is no harm to the bike's electronics system - the voltage is still well under any damaging level (only maybe 1-1.5 volt or so higher than the bike would put out) and it can't 'push' any more current than the bike would want to accept.

So - in practise - it would not even be an issue if the jumper was removed as soon as the bike is started - it's the length of time after starting that would be the issue - and of course the longer it remains connected, the bigger the possibility of R/R failure due to overheating with the bike's R/R in 100% shunt mode. And of course revving the bike in that mode will exacerbate & accelarate the R/R failure even quicker.

But why would it ever be necessary to have the auto running? The current required to start a bike will be more than adequately supplied by a cage battery. There is no requirement and minimal advantage in having the cage running from a purely system voltage perspective - if it won't start off a cage battery unassisted by it's alternator, then it's not going to start off a fully-charged bike battery either, so you have other problems to worry about!"

The S10 has a Mosfet R/R, which is SIGNIFICANTLY better than the straight up shunt R/Rs a lot of non-Yamahas come with...BUT

"MOSFET R/R is not dumb, but unfortunately too smart for own good - thinks it knows better and reacts according to what it interprets it should do. But missed that one important 'what-if' class due to frat party hangover, or would have realized that there was potential to not neccessarily believe what was obvious at first appearance. And so might also succumb to the same fate ultimately- but would take considerably longer to perish. Like lobster boiled from cold water as opposed to dunked directly into boiling water. That's suppsed to be 'better' right?

MOSFET is still ultimately a shunt device - just less power dissipated.
It would certainly survive much longer, maybe even not fatal. "

Wanna try it?

ac

 

[markjenn]

You're clouding the discussion with minutia. My assertion is the a S10's and a typical car's electrical system are regulated to approximately the same voltage, whatever the technology they use for regulation. Period.

BTW, just to add some actual data to the discussion, I just started my S10 and measured the bus voltage: 14.9V. I started up two of my cars: 14.7 and 14.8V. I guess I should be worried that if I jump the two together, the bike will fry the cars.

- Mark

 

[avc8130]

You're clouding the discussion with minutia. My assertion is the a S10's and a typical car's electrical system are regulated to approximately the same voltage, whatever the technology they use for regulation. Period.

BTW, just to add some actual data to the discussion, I just started my S10 and measured the bus voltage: 14.9V. I started up two of my cars: 14.7 and 14.8V. I guess I should be worried that if I jump the two together, the bike will fry the cars.

- Mark

Mark,

Yes, relatively the same voltage...but the capacity for how they arrive there is where the issue could lie. I stated you would NOT fry the "electronics" from the voltage.

I'm impressed your S10 charges that high...by FAR the highest charging motorcycle I have ever heard of.

In fact, WELL above spec.

Go ahead, plug them both together and let them run for awhile.

ac

 

[avc8130]

In fact, Yamaha specifically states in their manuals:

When charging a battery, be sure to remove
it from the vehicle. (If charging has to
be done with the battery mounted on the
vehicle, disconnect the negative battery
lead from the battery terminal.)

With the bike hooked up to a RUNNING car you are essentially "charging" the battery with the car's charging system.

Clearly charging the battery with the bike off isn't an issue, provided we keep the charging voltages reasonable.

It's the COMBINATION of both activities, running the bike AND the car that is the issue, and it isn't the voltage that is the main culprit.

ac

 

[markjenn]

And just to add more fuel to the controversy, I was just checking my S1000RR owner's manual for something and happened to notice this in the instructions for jump-starting: "Run engine of donor vehicle during jump-starting". And later in the process: "Allow both engines to idle for a few minutes before disconnecting jump leads". Apparently BMW isn't too worried about electrical system incompatibilities.

- Mark

 

[avc8130]

And just to add more fuel to the controversy, I was just checking my S1000RR owner's manual for something and happened to notice this in the instructions for jump-starting: "Run engine of donor vehicle during jump-starting". And later in the process: "Allow both engines to idle for a few minutes before disconnecting jump leads". Apparently BMW isn't too worried about electrical system incompatibilities.

- Mark

Mark,

That's good and it really shows the underlying point. The owners manuals come for a reason, they should be read and followed. What's good for the goose could kill the gander.

ac

 

[Mtbjay]

Entertaining banter. Got me thinking...

Has anyone successfully push started the S-10? Ya know, run like hell then pop the clutch?

 

[yz454]

Yes.

 

[Checkswrecks]

Entertaining banter. Got me thinking...

Has anyone successfully push started the S-10? Ya know, run like hell then pop the clutch?

The big draw is the starter motor. Push start will work IF IF IF you have enough battery for the fuel injection and electronic ignition.

 

[behindbars]

Entertaining banter. Got me thinking...

Has anyone successfully push started the S-10? Ya know, run like hell then pop the clutch?

Or if you're riding with a buddy, you COULD try this:

How to bump start or push start a motorcycle mx dirt bike

 

[merchant]

Entertaining banter. Got me thinking...

Has anyone successfully push started the S-10? Ya know, run like hell then pop the clutch?

Had to push start my S10 when I left the ignition in the run position to hold my ABS setting. I left it sit too long and drained the battery (DOH!). The trick to push starting an S10 is to put the bike in 2nd or 3rd gear, get up a decent head of steam and then pop the clutch. Best for someone to be sitting on the bike so the rear tire has good bite on the surface and doesn't skid. It took a couple of trys, but after starting it only took about 25 miles to charge back up (per the volt meter). Still, it was a nervous moment shutting the bike down to refuel. But she kicked over like nothing has happened. No problems since.

 

[avc8130]

Or if you're riding with a buddy, you COULD try this:

I've seen that done with 2 bikes on centerstands back to back.

ac