Originally Posted by Deepc View Post
2005.5 950A w/20,0000 miles.
Two weeks ago, I went to start my bike only to find that my fancy Shorai battery was dead. Upon further inspection the battery had actually melted. I put in another battery, this time a Yuasa, and she began to hiss and boil. I'm guessing that my voltage regulator is shot. What is the best way to test the voltage regulator?
I went through the EXACT scenario you describe above with
my KTM 950 Super Enduro. But it's easy to fix and the fix
will be much more reliable than the OEM regulator assuming you
take my advice and buy the best regulator available, as detailed
below. Don't be too pissed at the bike, it's not a huge expense to fix
properly and it takes maybe an hour at most to do the installation
of the new regulator. After you install the new part the bike WILL be
more reliable than it was from the factory.
I don't think you "need" to test the voltage regulator. It has
already destroyed one battery and perhaps the second battery also.
It's pretty obvious the regulator has failed and you need a new one.
But if you insist, here is how to check the voltage regulator :
1) set your voltmeter to DC volts and set the meter range to 20 volts
or whichever meter setting is not less than 20 volts but closest to the 20
2) Connect the positive test lead from your meter to the positive
pole of the battery which is connected to the bike's wiring harness.
3) Connect the negative test lead from the meter to the negative pole
of the bike's battery.
4) start the engine of the bike and watch the meter as you rev the
engine up to at least 3,000 RPM. You will probably see voltage in excess
of 16 volts. Any voltage in excess of 14.5 volts means the regulator is
malfunctioning. Don't run the bike any longer than necessary to perform
the test because overcharging will damage the battery. A Shorai will be
destroyed much quicker than a lead-acid Yuasa battery but any battery
will be destroyed by overcharging.
It is ESSENTIAL you make certain all the wiring which is related to
the battery and charging system is in good condition and is connected
as it should be. If some ground wires are left disconnected damage
can result. The failure in your bike is probably unrelated to the recent work
you did but you do need to make sure the wiring is in correct order.
Now, how to fix it.
You need a new voltage regulator. I suggest you avoid
buying one from Rick's Motorsport Electrics because the
regulator sold by that business is poor quality and there are
better regulators available from different sources for the same
The regulator you want is the Shindengen brand, which uses MOSFET
circuitry which means it produces dramatically less waste heat
during operation and is less likely to fail because of this circuitry.
The supplier I prefer to deal with is this one :
Roadster Cycle is owned and run by one man, whose first name
is Jack. He is extremely helpful and very knowledgeable and the
kits he sells are quite nice and much better quality than the stuff
sold by Rick's. If anyone tells you that Rick's sells top quality stuff they
don't know what they are talking about and if you take their advice
and buy that Rick's stuff you have only yourself to blame.
You need to perform tests to verify whether the rest of
your charging system is operating correctly, BEFORE you
install a new regulator/rectifier. This includes testing the battery.
You should charge the battery using a charger which is known
to be working properly and check the battery after charging to
see if it has been damaged or not.
You can find the info on how to check the rest of your bike's charging
system in the web page below. It is easy to check everything and takes
maybe 20 minutes at most. All you need to perform the tests is an electrical
multimeter which can work in AC volts, DC volts, and Ohms.