How many volts does your RR produce?

[mrkprsn]

Hi peeps,

This is more for the Direct Current Narrow Case crowd but early WC info might be valuable also. I am having RR issues and am interested in your experiences and opinions. Will you answer the following questions? Thanks in advance.

What RR, flywheel, stator and battery setup are you running?

How many volts does it produce with just the ignition (partial) load and also with ignition and lights (full load) at idle and 3000 RPMs?

Do you think a RR that produces 8.75 volts under full and partial load at idle and at 3000 RPMs is too much?

Cheers, Mark

[Jordan]

See the paragraph about charging, from Ducati narrowcase shop manual.
There are 3 cells in the battery, so total voltage when fully charged works out to 8.1 volts.
I'm not sure if that means it's measured with the charger switched on or off.
Your 8.75V does seem a high number.

I think 8.1V might be the "charger on" voltage. That coincides with what we've seen on "12V" car voltmeters from the analog days, when they were often showing 16V or more on the scale.

Charger voltage needs to be above battery voltage, otherwise the battery could not be charged.

[mrkprsn]

Jordan, Thanks for the reply.

I bought a new Duracell 14 AHr AGM battery and it blew up after 45 minutes of riding. The new Electrex RR I was using puts out 8.75V. The battery says to charge it between 7.2-7.5V. Maybe the older batteries were more robust?

I have another RR (without the charge light) that puts out 7.48V when the lights are on and 7.54V with them off. This is my "control group" RR. At least I know that the other electrical parts of the bike are working normally.

In 8 days I will be riding in a Motogiro where my bike will be running for 14 hours over 2 days. I think if I charge any 6V batter at 8.75 for 3-4 hours at a time it wont last.

I wonder if I can put a resister that drops the voltage 1.5V between the RR and the battery and have the RR thinks its charging at 8.75V but the battery is at 7.25V. Ugh.

Cheers, Mark

[Jordan]

Your idea to use a resistor to reduce voltage isn't something I've ever seen done, but might be worth a shot.
It'd need to be high current capable.
The voltage output would be lowered throughout the rev range, so you would not be getting much charge at low revs.

I'm suspicious of the Duracell battery that failed.

Does your bike's ignition work off the battery?
If not, you might be able to run the whole bike battery-free.
That would avoid the problem of blowing batteries.
My bike has no battery, but does have self-generating CDI - the standard electronic ignition of late widecase singles.