*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 amulti-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.
[color=#800080][color=#800080][font=arial]Reconnect the negative battery cable to the negativ

 

hi,can you tell me how to connect the wiring of a regulator/rectifier.I cut the wiring between the rectifier and plugs...I now that green goes with green,red with red,and there are three yellow wires...the question is: Is it important how do I connect the yellow wires between them?or not?

 

I have an honda cbr f4i from 2001

 

where is step 4

 

check out my pics

 

"A bike's charging system doesn't recharge the battery with full regulated voltage until above 5000 rpms or so."

This is not true. The charging systems on many bikes are capable of supplying full charging voltage a low RPM, some even at idle.

5000+ RPM is what the charging system needs to supply maximum power (volts x amps). Most charging systems will never supply max rated output power because the electrical load simply isn't there.

 

moar 4!

 

One other thing to check is the AC voltage coming from the molex connector that connects to the regulator rectifier. At 3000 RPMs, the acceptable range is 30 - 60 volts. If you are sustaining these levels at that RPM, the stator is working perfectly, and your reg/rec is quite possibly toast. If you run through the regular ohm testing on the reg/rec, you'll know if that's your issue.

I had the luck of getting ahold of a used reg/rec for free to test with and my conclusion was the one I had was toast, since ohm testing showed nothing and no voltage increase when RPMs increased, and now the new, used one over charges, upwards of 18 volts at 7 grand....

Moral of the stories:
1. Test everything the service manual suggests, which also helps you rule out other faulty parts that may break the new part you'll be buying.
2. Electrical components rarely show visible signs of problems, so when in doubt, just replace it, though a spare used part is sometimes good to give you an overall opinion.

 

where is step 4

 

My Problem.
1999 CBR 900RR

Last year I ran into some problems with the electrical system. I would have to jump my batter at times, and other times it would start on its own. If it wasnt starting I would jump it to prevent from completely draining the battery. The last time I rode last year I would be going into a turn and my bike would die, I would have to jump it through the turn, which wasnt very safe, so I decided to wait to fix my bike.

Testing my old battery I found that it was completely shot. Under a load it had 0V. I just bought a new battery, Gel, the dealership charged it for one hour. I put it in my bike, and I had no problems.... This was a few days ago. I rode two days in a row, she sat for one day, and today I went to start her and the battery was just dying.

Question:
Could the battery have not been fully charged from the dealership?
I checked the rectifier to see if the plug was fried, (right side under rear plastic mounted to frame) everything looked good.
I checked the battery voltage, 11.4V. I jumped my bike, and revving the RPM's it would go to 12.3V, then drop to 11.4/5 at idle.
Is my stator shot?

I am currently charging the battery, 2amp. I hope to see if the battery just wasnt fully charged and this fixes my problem.

Any help would be greatly appreciated, feel free to email me with suggestions at kevinvanderwiede@hotmail.com, or send a personal message through the site.
Thanks everyone! Enjoy the ride!