Bad Battery Or?

Thought my battery was dead. Just get a buzzing sound when I tried to start. Replaced the battery after quite a hassle. (Another thread) Rode the bike 156 miles last Friday including four starts with no problem. Went to start the bike this morning to get a new rear tire. Same buzzing sound. ;-( Thought I somehow developed a loose connection. Took it all apart, made sure everything fit well. Same thing. Used a voltmeter on the battery screw terminals. Voltage drops to zero when I try to start. Bike on center stand and in 5th gear,push on the tire it move and you can hear the cylinders move. WTF?

Get it load tested. Might be a bad one. If it was just dropping to a low voltage (i.e. 9V or so), I might suggest looking at the starter solenoid and starter motor. Zero volts suggests essentially open although it might show 12+V as long as there is no draw.
Of course, you need to make sure that cables are securely connected but you are measuring on the actual terminals?
(I have seen a case where the vinyl cover from the positive cable got tucked between the cable and the terminal preventing solid contact.)

You're not having much luck lately!

Have to take the battery out to load test it as there is almost no access to the positive terminal with the load tester.

Trying some other tests first. Now suspect the alternator.
Some other data points. Installed the new battery, put it on the tender, Removed tender and went for a ride (156 miles, four starts), got home and parked the bike. Two days later, it would not start. put the bike on the tender part of the day and it started normally. No time to ride for a couple of days. For grins, tried a start and it worked but to busy to ride.

The battery on its own went from 13.17V to13.05V in 24 hours and no drop in 5 more hours so the battery sounds okay. Setting up to measure drain of all "loads" on the battery when switch off. Then will check charging voltage with everything connected and vary loads; Moto Lites on/off, lights high/low. What should the minimum charging voltage be at idle?

Interesting that my riding buddy who restores Broncos guessed the alternator as the base problem.

Check system voltage. Start bike and rev to 3,000 rpm or so. If the charging system is bad, there will be little difference with engine running. (Should get 14V or so running.) You then need to narrow it down between the stator and the regulator/rectifier. (Or a bad connection somewhere along the way.) Measure the AC output on all three stator legs - should all be the same. Can also measure the resistance of the three legs - should be low and the same as each other.

Charge voltage with no load except engine and low beam 13.7 volts. Drops to 13.4 with Moto Lites (30W). Riding to the shop as I want to get it fixed while weather still good. In the middle of a big house remodel so no time to pursue further.

K_Flyer said:

Charge voltage with no load except engine and low beam 13.7 volts. Drops to 13.4 with Moto Lites (30W). Riding to the shop as I want to get it fixed while weather still good. In the middle of a big house remodel so no time to pursue further.

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Just a data point.

I'm on my fourth FJR. All of them measure(d) 14.2 - 14.3 volts on the battery while the engine is running at idle (no extraneous loads), after maybe a few seconds at 13.7-ish immediately after starting.

This one is a real puzzle. Got the bike back from the dealer. They say the charging system is working correctly except the Cycle Gear battery is crap so installed a Yuasa. They also say the Moto Lites are too much of a load on the system. Odd as I've been using them on many bikes and had 65k miles on this one with no problem. They are 100W. Came home from the shop (50 miles), checked the charging voltage with the Moto Lites off and it was 13.6V! Attached the battery tender. It stayed in the red for over 4 hours which tells me it was quite depleted.

Tried again this morning after the battery was 80% charged and the charging voltage was 14.1 @ 4k! This was with the Moto lites off. Turned them on and it dropped to 13.7V Will do more tests later when a buddy comes by to help, observe and speculate.

At this point I speculate that the alternator is the problem. Part of it is not putting out. Stay tuned and pass along any ideas.

I, for one, approve of putting out.

Update;

Battery voltages measured at battery tender leads. Battery has been charged past 80%
Key off 13.67
Key on 12.7 and slowly falling
Running 14.14 @ idle
14.17 @ 4 K
Lights on 13.8 @ 4k

Reserve capacity is 325W, moto lites are 100W. When the battery is depleted, there is not enough reserve capacity to charge the battery in a reasonable time.

My conclusion is that part of the alternator stator is not working.

The question is do I bite the bullet and replace the stator or do I give up the moto lites and heated grips and...?

Based on your measurements, I would check the resistance of the three white wires coming off the stator and going to the regulator/rectifier. You should check 1-2, 1-3, and 2-3. They should all be the same as previously mentioned. For ‘16 and newer, the spec is .128-.192 Ohms.

If that checks out, I’d be checking wires between stator and regulator and also regulator to battery. Then I’d probably throw a new regulator at it based on what you’ve done already.

ksiesel said:

Based on your measurements, I would check the resistance of the three white wires coming off the stator and going to the regulator/rectifier. You should check 1-2, 1-3, and 2-3. They should all be the same as previously mentioned. For ‘16 and newer, the spec is .128-.192 Ohms.

If that checks out, I’d be checking wires between stator and regulator and also regulator to battery. Then I’d probably throw a new regulator at it based on what you’ve done already.

Click to expand...

Also check that ACV are the same on each leg while operating...

Thanks for the tips. Looks like I need to take the side panel off to get at the wire. From YouTube, it looks like the newer ones had easier access. Unfortunately, can't rely on the shop any more. I'm not as flexible as I used to be. I'll work something out.

K_Flyer said:

Update;

Battery voltages measured at battery tender leads. Battery has been charged past 80%
Key off 13.67
Key on 12.7 and slowly falling
Running 14.14 @ idle
14.17 @ 4 K
Lights on 13.8 @ 4k

Reserve capacity is 325W, moto lites are 100W. When the battery is depleted, there is not enough reserve capacity to charge the battery in a reasonable time.

My conclusion is that part of the alternator stator is not working.

The question is do I bite the bullet and replace the stator or do I give up the moto lites and heated grips and...?

Click to expand...

This is a tough one. Good voltage at idle. Not so good with lites on. Why don't you try voltage without the lights on, but heated grips and any other accessories you may have just to make sure the lights aren't somehow drawing more than 100 watts?

That 13.8 volts is low. Could be the stator, regulator/rectifier, or a connector, but I would suspect the stator. Still, rare for any of those parts to be a problem on a Gen 3. How many miles on it?

Odd, even at 13.8 volts that it ran your battery down previously. At that voltage it shouldn't have. Something is amiss here. Something is missing.

Good luck.

Some of us with the early GenII's had to install a new harness coming off the rectifier??

Roadster cycle

Panman said:

Some of us with the early GenII's had to install a new harness coming off the rectifier??

Roadster cycle

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Yup. I had to do that. And helped another diagnose the same issue. But I have never heard of a Gen III doing that.

Bike has over 65k miles. Problem just appeared a few weeks ago. I'm also surprised that battery discharges at 13.8. I'll try some of the other suggestions. But winter is coming and I think I will ride without the moto lights until I can get to checking it out. Wish I could find a mechanic in the area that I could trust. I have too many problems with back and knees to do much myself. Picture is of me at least 25 years ago. I've worn out somewhat since then.

K_Flyer said:

This one is a real puzzle. Got the bike back from the dealer. They say the charging system is working correctly except the Cycle Gear battery is crap so installed a Yuasa. They also say the Moto Lites are too much of a load on the system. Odd as I've been using them on many bikes and had 65k miles on this one with no problem. They are 100W. Came home from the shop (50 miles), checked the charging voltage with the Moto Lites off and it was 13.6V! Attached the battery tender. It stayed in the red for over 4 hours which tells me it was quite depleted.

Tried again this morning after the battery was 80% charged and the charging voltage was 14.1 @ 4k! This was with the Moto lites off. Turned them on and it dropped to 13.7V Will do more tests later when a buddy comes by to help, observe and speculate.

At this point I speculate that the alternator is the problem. Part of it is not putting out. Stay tuned and pass along any ideas.

Click to expand...

Disconnect your plug and check to ground. My stator was grounded. Voltage would be good in light loads but if I loaded it up with gloves, vest or aux lights it would drop
Good luck.

Guys, I had an issue a couple of years ago that sounded similar on my Gen1. It turns out that using a battery tender on a bike inside a HOT garage actually ruins the battery and causes all the issues that made me change the starter and battery twice. Once I quit leaving it on a tender in my garage except in the winter, I never had that problem again. My understanding that not using a smart tender and hot garage causes the cells to burn up. Maybe worth looking at?

EddieB said:

Guys, I had an issue a couple of years ago that sounded similar on my Gen1. It turns out that using a battery tender on a bike inside a HOT garage actually ruins the battery and causes all the issues that made me change the starter and battery twice. Once I quit leaving it on a tender in my garage except in the winter, I never had that problem again. My understanding that not using a smart tender and hot garage causes the cells to burn up. Maybe worth looking at?

Click to expand...

I am having trouble buying into this. I live in Phoenix, have had multiple FJRs over the years as well as a few other bikes. I always keep them on a tender and haven't had these issues. And I can guarantee it is hot in my garage! Hell, today's high was 95 degrees! Now since I have multiple bikes and only a 'few' tenders when I say I keep them on all the time I mean I rotate them regularly. A bike may be on a tender for days, or weeks at a time, then be rotated off for days or a couple weeks.

Heat is definitely hard on batteries! But so is not being fully charged. When I had my Harley 20 years ago a battery would only last one, or two years at most in this hot climate. OEM FJR batteries generally last 4-5 years. Replacements 1-3 years. I know buy only Antigravity lithium batteries. I haven't had to replace one yet. Oldest is 9 years old. 2nd oldest is 5 years old. But quality doesn't come cheap.

Perhaps there was something wrong with your battery tender and it was over-charging it?

100 watts of extra lighting shouldn't be a problem for the 590 watt FJR alternator. That's only 7 amps or so. Heck, sitting at idle with the brakes and turn signals on is 80 watts or so. I'd be curious what the output on the red wire from the Regulator/Rectifier is, using a clamp-on DC ammeter (if available). The spec says the system should be capable of delivering 40 amps at 5,000 rpm.

Do you have access to an oscilloscope? Looking at the battery voltage while the bike is running and charging should show an AC waveform of regularly spaced positive-going crests forming a smooth ripple that increases with RPM. An irregular pattern is a sign of charging system trouble. For example, if every third crest is missing that suggests a blown regulator diode or failed winding. A negative going third crest suggests a shorted regulator diode.

A less accurate and reliable check can be done with an AC voltmeter, which can't show patterns but at least can measure the AC ripple. If the AC voltage is more than, say, 100mVAC, there's a problem.

A common problem with motorcycles in general is corroded connections between the alternator output and the rectifier/regulator input or between the regulator output and the battery. The FJR uses a permanent magnet 3-phase alternator system. Rather than vary the alternator output, this system runs the alternator at full output all the time and simply dumps excess current when the demand is less than the output.

There are 3 white wires going into the R/R from the alternator. The contacts should be clean and bare. Any corrosion on a contact will reduce output from that leg (and often results in partially melted plastic connector housing due to excess heat generated by the poor connection).

With the 3 white wires unplugged from the R/R and the engine off, set your resistance meter to the x1 ohms scale and measure the resistance between each pairing on the harness side. The resistance should be low -- around 0.5 ohms -- and equal. A high resistance indicates an open winding or broken wire.

With the red and black wires disconnected from the R/R, measure the resistance between the red and battery + then the black and battery -. It should be near 0 ohms in each case. High resistance suggests a poor connection somewhere.

With the engine running, measure the voltage between each pairing of the white wires on the harness side. The AC voltage between any two of the three should be equal to the voltage between each other pairing at any given rpm. IE: 1-2 = 2-3 = 3-1. (Seen on a scope, each pair should show a nice even sine wave.) Significantly lower voltage on any pair indicates a failed -- probably shorted -- winding in the alternator.

If everything else passes, replace the R/R.