how to diagnose the charging system

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how to diagnose the charging system

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how to diagnose the charging system - 10/10/2007 11:01:46 AM

HAVOC

Posts: 3881
Joined: 6/27/2006
Status: offline

*written by abadfish*

Okay, so your battery isn't holding a charge. Time to get a new battery??? Hold on there....the battery may be a symptom and not the cause. Charge your battery with a charger and go throught this tutorial to see which part of your charging system is failing.

What components make up the charging system?
The charging system is made up of essetially three compoenents:
- battery
- alternator (used interchangeably with stator)
- regulator/rectifier

The battery is the rechargeable power source for all electrical devices on the bike.

The alternator generates power to recharge the battery.

The regulator/rectifier is the link between the battery and the alternator. The battery is a DC power source. The alternator is an AC power source. The rectifer converts AC to DC. The regulator probes the battery's voltage. If it is low, it allows the converted AC power to recharge the battery.

Many of you are familiar with charging systems of cars. Motorcycle charging systems are similar in concept to automobiles but do have some differences. Unlike a cars charging system, a motorcycles battery is still in use to power all electrical devices. Therefore, the battery cannot be disconnected even after the bike's engine is running. Also unlike a cars charging system (which is recharging the battery with full regulated voltage as soon as the engine is operating), a bike's charging system doesn't recharge the battery with full regulated voltage until above 5000 rpms or so.

Charging System Diagnosis
This tutorial uses an F3 but most of this information is applicable to most bikes. It is assumed that you know how to use a multi-meter.

Tools required:
- multi-meter
- assorted tools to remove fairings and the seat

Step 1 - Check Battery Voltage
- Remove the right side rear cowl, seat, and battery cover.
- Measure the DC voltage of the battery. It should be above 12.3 V.
- Start the engine and measure battery voltage @ 5000 rpms. Voltage should read between 13.5 and 15V
- Turn the engine off.

If the voltage was correct, go to Step 2. If it was incorrect, go to Step 4.

Step 2 - Check Current Leakage
- make sure ignition is off
- disconnect negative battery cable
- connect the postive lead from the multimeter to the negative battery cable
- connect the negative lead from the multimeter to the negative battery post
- measure the current leakage

NOTE: this step can cause damage to the multimeter if it is not set up properly for current readings. Check your mulitmeter's owner's manual for proper setup.

The current leakage should be no more than 1.2mA (this value may vary for your bike). If the current leakage is correct, the battery is faulty. If it is incorrect, continue on to Step 3.

Step 3 - Disconect the regulator/rectifier
- locate the the regulator/rectifier on the right side of the subframe. Disconnect the plug to the regulator/rectifier.

If continuing from Step 2, redo the current leakage test. If the current leakage is still incorrect, there is a short in the wiring harness. If the current leakage is correct, then the regulator/rectifier is faulty.
Reconnect the negative battery cable to the negativ

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