HELP volatge problem

[tabor410]

i have a voltage problem the battery is putting out 12.5 volts. the voltage going to the battery is only 3.5 volts tried a different voltage regulator and same problem. any help would be greatly appreciated thanks (03 derbi gpr50r)

[RS_Patrick]

Try to give more details in your posts, now i have to guess half of what you mean.

I guess you mean the battery is not being charged? so stuff that runs of the battery does not work?
Do the Headlights etc. work?

Theres a wire that comes from the engine/stator, that does not go to the Ignition unit, but probably straight to the regulator. mesure how much Volts AC you got on that.

[tabor410]

Lights and accessories work on a fully charged battery. After running the bike the battery is depleted. Will not start = dead battery. Voltage going to batt is only 3.5. Tried a new voltage reg same results. I measured voltage going into the battery to get my reading of 3.5. ANY suggestions? Could it be the stator? Where can I measure the stator output from?? Any other leads and or suggestion?

Any help would be appreciated. Thanks in advance:

[JimmySR]

stator output goes to the CDI, measure them there, but to measure that you'd have to be pushing the starter button, and its not gonna be pushing out much with a flat battery, so forget that.

chances are either your battery is fked, as in it wont hold a charge, or your regulator has gone. Whilst the bike is running, the battery should be getting charged through the regulator, but if yours is blown, its not gonna charge the battery, giving you the symptoms youve got.

Had your stator gone, you'd find trouble getting a decent enough spark to fire the bike up. Does the bike bump start fine?

Gluck

[tabor410]

So am I right that we now have two defective voltage regulators? The new one and the old one. The battery is a brand new ,and is charged up after every drive. If not there is not enough juice in the battery to turn it over.

[RS_Patrick]

At Jimmy: CDI circuit is completly seperate from the Light/Battery circuit mate... has nothing to do with each other, completly difrent coils and wires.

>>>>>>>>>>>>>>>>>

At Tabor410:

A: Headlight, Dashlight and Taillight do not work from the battery, but directly from the Stator trough the Regulator, Battery powers the Starter Motor, Indicators, Brakelight, Horn, Neatral Light, and Gauges but if the battery is weak or defective and you the engine runs they get power from the Stator trough the Regulator trough the Rectifier trough the Battery though usualy only enough for them to work corectly if the bike is at over 5000rpm.

B: Did you messure the values at with a running engine holding it at 6000rpm?

C: Did you look at the wire that comes from the Stator (engine) and goes to the Regulator? and did you messure the voltage on that? (again at 6000rpm)

[williamr]

Where did you measure the 3.5V? Across the battery terminals is where you need to measure the voltage. With the engine off you're measuring the battery voltage. With the engine running at about 6K rpm you're measuring the voltage going into the battery, unless it's less than the battery voltage, in which case you'll measure the battery voltage. You're doing something wrong. If the charging circuit is OK then there will be about 13.5 - 14.5V across the battery terminals at 6K rpm.

On this bike the single phase stator feeds a regulator first, which feeds AC to the lights, then a rectifier which converts it to DC for the battery, horn, indies and dash. Regulatr and rectifier are seperate units on this bike. To check the stator it should be disconnected from the regulator to check off load, and the voltage measured between the thick yellow(?) wire and ground. It should be about 30VAC or higher at 6K rpm. Make sure that the meter is set properly. If it's set to DC when you're measuring AC, or vice versa, the readings will be very wrong.

If the stator output is OK, reconnect it and check the ac voltage for the headlights. Look for about 14VAC. This is the voltage out of the regulator. The rectifier output is connected directly to the battery and is obviously a DC voltage.

While you can disconnect stator and regulator, don't run the engine with the battery disconnected as high voltage spikes from the ignition primary can fry any electronics. The battery acts as a damper to prevent this.

The other stator connections - to the CDI - provide power and timing pulses for the self energising ignition. They have nothing to do with the battery charging or lighting circuits. It's quite possible for the charging coil in the stator to fail without affecting the ignition coils.

Rob