BATTERY CHARGING FAULT

start the bike (you can use a car) put a multimeter between the battery terminals give it a rev, if the voltage is anything between 14V and 15V then i'd say the battery is at fault.

if you've got no power at all check the fuse

you might want to check that the connections clean them and make sure they are tight.

 

Just my own observations from my old bike in a previous post

Check the battery voltage with the engine running and above 3000rpm and you should see 13.5 to 14.5 volts dropping to 12.5 - 13volts when idling. This indicates that your battery is charged and alternator and R/R is working ok.

If the battery drops below 12 volts with lights on when idling or engine stopped, then your battery is not charged.

 

Do u mind to help me find the location of regulator of 1993FZR250(3LN). Ppl said it is hanging aside the rear seat frame, but 3LN seems to be different to 2KR. Thanks

 

Im assuming that then if im having 12v dropping to 11v while on idle lights on and getting a reading of 15v out of the generator to the rectifier but only 9v out of the rectifier (red+neutral) my rectifiers shagged...

 

It's hard to get a good meaningful measure of the alternator unless its disconnected from the R/R. Just measure battery volts with the lights on and at 3000+rpm. You should get over 14volts.

 

cool thanks dave, she's toast then

 

Hi wolfman jack and co,

Once batteries start to build bridges in themselves they cause trouble. Most batteries are designed to last a year only and anything after that is a bonus. There are some ways to help your battery have a longer life. Of course there is that battery stuff that you can buy from supercheap. But my trick is to add a quarter of a teaspoon of epson salts to each seperate battery cell. Epson salt helps the battery generate power more effiently and acts as a catylist. Avoiding the battery check all electrical connections with a multimeter. You are checking for continuity, (each wire is connected to the other wire after the wire connection) just turn you multimeter to the mark called 20K. Test by connecting positive and negative on the multimeter, it should read 1. Thats enough for today best of luck.

 

Ok Natas - I would have to disagree with the 1 year for a battery. I would expect a minimun of 3 years if it is not abused, i.e. run dead flat several /many times or overcharged.

At my workplace I replace all our UPS backup batteries at a 3 year interval. This has been selected as a compromise between battery life and cost of failure. Admittedly these are sealed lead acid (gel) cells but we end up having lots of good 12v batteries going out for flounder lights etc. We have had no failures since doing at 3 years..

BTW wolfman the alternator would put out something like 50-100 volts AC at high revs when it is disconnected from the rectifier/regulator. The alternator is 3 phase (with 3 output wires) and that voltage should be measured equally in all 3 combinations of connecting to those 3 wires.

 

Hi Dave,
I agree that batteries do last longer than one year. Manufacturers will generally give you a one year warranty. Therefore they expect their batteries to last successfully for one year under nearly any condition. On reading if the bikes system is working correctly it would be best to read amps that it is pushing over the volts. Generally electric systems will not give trouble, and that is why I suggested checking the continuity of all wires to rule that out before you chase your tail tracking down the fault. This is the first step to take and this could also show that there is a fault. Remember these bikes are getting long in the tooth and things just wear out. Keep up the good work Dave and we will eventually figure this bike out.

 

Just a bit of theory on how alternators work, it may help in diagnosing problems. As wolfman correctly points out, check your wiring and connections as well, as these are usually inexpensive first things to check.


Bike alternators work differently to car alternators, in that to control the voltage in a car system, the alternator has a rotor that is a wire wound electro-magnet.
The current to the rotor is controlled by the regulator. This is the regulator's sole purpose in life. If the output voltage gets low, the regulator feeds more current in to the rotor which increases its magnetic field strength and hence more output to the battery from the stator windings/rectifier.
A car alternator will not usually generate enough current to excite itself without a functional external power source (the battery). This is why it is almost impossible to run-start modern cars with a dead flat battery


A bike alternator has a rotating permanent magnet so its field strength is fixed. As the revs increase the ouput voltage from the stator increases, 50-100vAC (disconnected) at speed is not uncommon. The regulator in this case senses the battery voltage and once it gets up to its ~14 vDC shorts out the alternator windings with a high power thyristor. This is done at a very high frequency so that the alternator output still appears to reasonably smooth. So at all rpm above approx 2000rpm the alternator is always putting out its maximum current which increases with rpm.

Not sure what volts the alternator windings puts out when connected to a normally functioning R/R, but I would expect 15-20volts AC at revs, but this may be difficult to measure with a digital multimeter due to the switching pulses.

The current used by the bike is generally fixed (lights & ignition with fan and horn the only big variables) and the excess current is dumped to ground by the regulator, which explains why they get so hot.
The output windings of the alternator are designed to handle this continual shorting out and also are self limiting to some degree in their ability to provide current as the revs increase and so a bike system can run into problems if extra load (E.G. extra driving lights) is added.

Under 2000rpm the alternator is not putting out enough voltage/current to run the bike and so the bike runs off the battery.

The FZR is notorious for running batteries flat in hot weather while riding in heavy traffic conditions where the bike is idling a lot, the fan is running almost continuously and particularly if using higher than standard wattage headlights.

Bike alternators will self excite with a flat battery if enough revs are on the engine.

Bloody hell - that is one long winded post. Hope that helps with the problem in hand.

 

Holy crap dave, thats a mighty fine effort...


Extra quick question: No continuity between any pins on the rectifier shows its shagged, eh?

 

Hi wolfman,

How are you testing the rectifier. If you are disconnecting the device and testing it that way you may not get a continuity reading because the electronic setup inside is not connected to each other. Therefore you will not get continuity. Testing for continuity is done by placing one end of the multimeter (positive or negative) in one end of the connection and the other end of the multimeter on the other side of the connection. All this test does is check that your wires are actually connected where they plug together. Hope this helps. If not give some more info on what you are doing.

 

Hi wolfman,
Bit more info on how the bike generates electricity and whats involved.

The stator is a set of wire coils. As the bike runs a magnet spins inside the stator inducing an electical current in the stator. That current is an AC (alternating current) current. From there it goes to the rectifier which is a set of diodes that convert the AC current to DC (direct current) current. Then there's the regulator which is a circuit that controls the DC voltage output of the rectifier so that you will charge, but not overcharge, the battery, and also continues to run the electricals on the bike.

This might make the picture clearer on how it all works.

Moreover coils are generally covered in a white coating, if this coating goes dark brown it is generally a sign that it is stuffed. And if the coil gives continutiy within itself this is another sign that it is stuffed.

 

I presume you mean the 3 (white?) wires out of the alternator. Measure across any 2 of the wires at medium revs, unplugged from the R/R.

You should get a high reading 50-100volts AC. If so the alternator is ok. Reconnect it.

If the alternator is good, the engine is running (medium revs) and you have 9Volts-DC (red+neutral) at the rectifier and 11.5-12Volts at the battery, you have a wiring/earth problem.

If the engine is running (medium revs) and, if you have a good battery and 12.5volts or less at both the rectifier and battery, then you R/R is shagged.

The battery voltage should rise when you give a good rev of the engine above idle.

 

I only have specs for a 3LN model.

The no-load output voltage is specified at 14.3-15.3 volts-DC
Stator coil resistance is 3.6ohms (+/-20%) winding to winding
Output 14v 19amps at 5000rpm
Rectifier 25amp & withstand 200v

Is the regulator separate to the rectifier ?? It's funny that they give specs separately for the rectifier and reg..

edit: when the alternator is unplugged (engine stopped) it should measure infinite resistance between the white wires and ground (I would say at least over 1meg-ohm would be ok)

 

Thanks dave, thats awesome i'll go thru my results. I did the checks as in: voltage @ battery before starting 12v, started and turned lights on, disconnected r/r and checked @ 2000-3000rpm = 46.7v, reconnected and checked battery @ 2000-3000rpm and got only 11v.....rest in peace rectifier <!-- s:cry: --><img src="{SMILIES_PATH}/icon_cry.gif" alt=":cry:" title="Crying or Very sad" /><!-- s:cry: -->


edit: resistance between stator coil windings 1.4ohms ?? Contiunity of stator coil windings to neutral nil (which is good, you dont want a short to earth)

 

I believe I have a failed battery; thought I'd see if someone might have the knowledge/experience to confirm this.

Basically I've never had a battery problem (in the 4 months I've owned the bike). But last week when I got to work, I must have had a brain fart. I went out to where it was parked a couple of hours later, and found my key in the ignition, and in the on position. (Must have more than our fair share of honest people over here in Perth!)

But yeah, the battery was dead flat. Put it on trickle charge for a few hours, and it started the bike no worries, and all was good for a couple of days. Then I didn't ride the bike for 2 or 3 days, and came back to find the battery pretty flat - turned the engine over weakly but not enough to start it. Was able to roll start it, but this has happened on and off all week now. If the engine's warm and it hasn't been too long since I rode it, it'll start, but leave it overnight or after work it won't start.

I should note that when I put the battery on charge, I checked the fluid levels and found them to be down anywhere from 3/4 to half. So I topped them up with distilled water. But I have a feeling it's not good to have a battery run flat with low fluid levels?

Is it worth bumbling around with this (more charging, epsom salts as I read previously in this post(!)) - or should I just go buy a new battery?

 

If the fluid levels were that low, then the battery already has had a hard life. Chances are it is not likely to recover from being run flat.

I have in years gone by, emptied out the battery into a plastic bucket, washed out the cells and put the best of the acid back in.

WARNING: ACID WILL BURN - wear protective goggles and have plenty of water on hand.