Fz6 S2 ABS - stator alternator, R/R or battery

[Bogdanphb]

Hi guys,

I have the following problem with the bike and I don't really know what to change. I've noticed the battery gets to the point where it's that weak it won't start the bike. It happens if I stall the bike a couple of times without any high RPM ride or I practice slow speed drills for about 15-20 mins and then shut the engine and start again repetitively. Basically, what the bike tries to tell me, if you stop and start the engine multiple times 3-5 times within a short period of time or if not going up to 5k RPM the battery will not be flat but won't have enough V to start the bike.
Today when I faced the problem, after a series of slow speed drills, went to a ride for 10min with higher RPM, shut the engine, started again, went slow RPM through a pedestrians area, had to shut the engine again and walk beside the bike before I would get a fine, when I tried to start it wouldn't start. Checked the diag for battery V, 11.5V. Had to basically just walk beside the bike for 10-20mins to get some passive power, eventually it started down a slight hill. When I got home after 30mins of riding at no less than 5k RPM, D:09 showed the battery has 11.9V. In diag history I saw code 46 which I reset before I went on a ride today, but after this episode no faulty codes appeared.

A week ago, got the multimeter and tested the battery voltage at idle, after I fully recharged the battery 12.6V, it was still around 12.3V after few days of riding with less to no slow speed drills. The stator resistance between 0.3-0.5, charging to 13.6V ( it would not get to 14V unless maybe I would have held the throttle @5k RPM for a long period ), R/R readings were 0,0,0 ~600,~600,~600. I checked the harness, everything looks connected correctly with no damage or corrosion.

I may think to change the battery, although the previous owner changed it a couple of months ago but I had to recharge it 3 times till now. What would you guys advise me to do ?

Thank you.

 

[TownsendsFJR1300]

Charge the battery and LOAD TEST it.

 

[Gary in NJ]

There is a test for everything in the electrical system. As Scott mentioned above, the first step is to ensure that you have a fresh battery, clean terminals and a solid ground. Are you getting 14VDC @ 5k rpm at the battery terminals (I think at idle you should see around 13VDC)? Get through these tests and if you are not getting 14VDC @ 5k with a fresh battery we can discuss the other tests to trouble shoot the electrical system. It's all very simple, each only takes 15-30 minutes.

 

[bryancraftyhands]

I quote this from someone at another forum who seems pretty keen on automotive electrical systems. Thank Cardoc at Subaru Outback org.
"Check the amperage output of the battery and compare it to the CCA rating. It needs to be at or above the CCA rating and if it's not you need a new battery."
There are instructions online how to do so that will pretty much say the same thing.
Plus what was said above.

 

[TownsendsFJR1300]

https://flic.kr/p/LDtUch

 

[Bogdanphb]

Thank you very much guys, I will change the battery for now and I'll come back with a video of how the readings look on mine.

 

[Bogdanphb]

https://flic.kr/p/LDtUch

Scott would you please tell me how you did the load test ? I do have a multimeter but the only thing I did was to connect it to the battery, positive/negative, switch it to DCV and reved it to 5k RPM. Is there something I miss ?

 

[Gary in NJ]

Scott would you please tell me how you did the load test ? I do have a multimeter but the only thing I did was to connect it to the battery, positive/negative, switch it to DCV and reved it to 5k RPM. Is there something I miss ?

So that's not a load test, that's a functional test. The battery has a static charge of 13.26VDC (likely LFP chemistry) and it drops to 10.51VDC during engagement of the starter. That's a healthy start. If it drops below 10VDC the bike would likely NOT start - especially if it required extended cranking. While not an actual load test it shows the health of the system. An actual load test puts a sustained load on the battery to determine of it can supply enough current to start the bike - because current is more important than voltage. Current is VxA...so only knowing V only gives us 1/2 the story.

 

[TownsendsFJR1300]

Correct ^^... The video was made years ago just to show charging voltages.
It should be noted I have the dual headlight mod (some slightly more draw).

The higher static voltage displayed is because it just came off the battery charger.
Had the battery been sitting, it would have shown lower.

Lastly, as I re-call, that battery was due to be changed out. When my dash illumination
goes out momentarily when activating the starter (a load), it's a hint to pay attention
to the health of the battery.

.

 

[bryancraftyhands]

I'm not sure how current / load test are done on a vehicle battery. Typically a DC system is tested with a multimeter in series, but most multimeters have a maximum load rating of 10 amps. Starters can and usually do draw much more. Last I looked I think ours draws at leat 95 amps. Clamp style ammeters work on inductive principles and only on AC as far as I know.
You can take your battery to a local LAPS and they will usually hook it up to their in store tester at no charge. I did it with a jump starter pack's battery.
Also, what @Gary in NJ mentioned above on the dropping below 10v is as good a field test as any.

 

[Motogiro]

I'm not sure how current / load test are done on a vehicle battery. Typically a DC system is tested with a multimeter in series, but most multimeters have a maximum load rating of 10 amps. Starters can and usually do draw much more. Last I looked I think ours draws at leat 95 amps. Clamp style ammeters work on inductive principles and only on AC as far as I know.
You can take your battery to a local LAPS and they will usually hook it up to their in store tester at no charge. I did it with a jump starter pack's battery.
Also, what @Gary in NJ mentioned above on the dropping below 10v is as good a field test as any.

What your saying about having the meter inline and testing for current draw is correct but a load test is different. A load test is basically putting a larger current draw on the battery by putting a load across the terminals, in parallel, and measuring voltage drop across the terminals for a specified time. This shows how the battery performs under a load to give an indication of the battery health.
There are quite a few load testers on the market. There are computerized types that you'll likely see in most professional settings but the old analogue type with a high wattage resistor and analogue meter are more economical for those of us that use it once in a while. I have a cheap analogue that does a great job! Harbor Freight or https://www.amazon.com/Neiko-40510A...rds=battery+load+tester&qid=1689430459&sr=8-5

 

[TownsendsFJR1300]

^^^, is exactly what I have..

 

[bryancraftyhands]

That explains something I've been missing. Thanks!

 

[Bogdanphb]

Hi guys,

Today I got the new battery installed. This is what it looks like :

Do you think it could've been just the battery ?
Do you think the considerable high volt fluctuation after I started the bike is normal ?
Should I take the bike to a shop to have it thoroughly tested ?

Thank you a lot for all the help provided!

 

[TownsendsFJR1300]

The battery wouldn't cause the very erratic #'s while running.

And those #'s are VERY, VERY erratic / not normal.

At times it shows it charging, other times not-That leads me to believe the
voltage regulator may be the issue.

Inspect and / or replace the unit. That'd be cheaper than a shop visit-(Which is what they'll do)


Also, the LEDS don't draw anything unless their turned on.


.

 

[Gary in NJ]

I don't like what I see here...your charging system is taking too long to recover after a start and the voltage is generally low.

Regarding your initial questions in the video, the aux-lights will not draw current when not engaged. The phone charger likely has a parasitic drain on the battery if it is a USB device. If it doesn't have an off switch, there will be a 5-10mA drain that will discharge the battery.

On to the charging system.

The first thing I would do is to disconnect the connector between the stator (3 white wires) and the voltage regulator/rectifier (herein refered to the r/r). Make sure that there isn't any corrosion in ether side of the connector, check for burning or signs of high temperature, and check that the wires don't feel stiff or brittle. For the sake of good order, clean both sides of the connector with a spray contact cleaner. If all of that is good, now is a good time to conduct a test of the stator.

When there is low voltage we want to check the condition of the stator coils. Start by checking for continuity of the coils - no continuity is good, any continuity is bad. Check for continuity between each of the white wires and a ground on the frame. If you find one or more legs with continuity you have a burned coil on that leg.

Now set your multimeter for resistance and check wire to wire: W1 to W2, W2 to W3, and W3 to W1. You should see about 0.22 to 0.34 ohm resistance. Any open is bad, and continuity is good.

With the stator still unplugged from the r/r, start the engine and check the AC voltage output between the white wires: W1 to W2, W2 to W3, W3 to W1. There isn't a factory spec for this test but you are looking for a minimum of 60 VAC (yes, it's AC voltage) at idle and around 75VAC above 4000 rpm. Exact output is not critical but should be about the same for all 3 legs and above 60 volts. Voltage varies with RPM. If any of the stator coils are shorted to ground, the stator AC voltage output can still test OK open circuit, but when you plug it into the r/r it will not work because you have a common ground for both the AC input and the DC output. That is why you must do (and pass) all 3 tests.

If you pass those tests you can move on to testing the r/r. Remove the r/r from the bike so you can test the internal rectifier diodes. Put your digital meter on diode check. Check red wire to where the white wires connect then reverse the test leads. You will get no continuity one way and about .5 volt drop fwd continuity the other. Now repeat the test black wire to white wire connector. You should get the opposite results for no continuity and fwd continuity with a .5 volt drop.

Unfortunately there is no way to test the regulator part of the combined r/r unit, except by elimination of all other problems, or substitution with a known good one.

 

[Bogdanphb]

Alright guys, I managed to do the stator resistance, output, and rectifier test. I hope I did not miss something and I did it correctly. I found some info about stator output which should be ~18V per 1k RPM, 2k would be 36V and so on.
However, my main concern is that fluctuation, and the idle sound of the engine, seems like it’s fighting to keep the revs up. I changed the spark plugs recently, it was worse before, and the rev needle was up and down, now it’s stable but that slight sound it’s there.

Looking forward to suggestions, hopefully I made it clear! Thank you a lot guys, you are of great help

 

[bryancraftyhands]

If you're geeting and erratic, or not getting a steady electrical output, your spark plug's current may not be consistently strong enough to spark / ignite.
The only other guess I can offer is if your carbs / throttle bodies need synced.

 

[Gary in NJ]

It looked like the AC voltages were 66, 86 & 78. Did I read that correctly? They should all be within a few points of each other. The 66 VAC is the real outlier. Also when the meter was displaying 0.9 ohms you were noting it was 0.3 ohms - why was that?

 

[Bogdanphb]

It looked like the AC voltages were 66, 86 & 78. Did I read that correctly? They should all be within a few points of each other. The 66 VAC is the real outlier. Also when the meter was displaying 0.9 ohms you were noting it was 0.3 ohms - why was that?

Last 2 tests were above 80, the first one 66, I may have not rev it to exact same rpm. And I said it’s 0.3 because when I touched the pos/neg ends of multimeter it shown 0.6, then I just subtracted that from 0.9.