[zsiros]

Hello everyone

I got my first issue with my RE classic 500, 2018 ABS model with 9000kms (1st owner bought it in 2020). Battery stopped charging, went for a 300km trip, after the first stop, the battery was so weak it did not start with the electric starter, kickstarted it without an issue. The next day when returning, it got weaker and weaker until it did not even try to turn it over with the electric starter, thankfully the kickstarter saved the day. I got pretty lucky this time as it finally died about 5m from my parking space.

When it comes to electronics I am a total newbie, but I want to learn to fix my own problems with the bike. What I did so far is check the fuses, battery connections, and if there are any visible wire damage and/or plugs unplugged. Did not find any issues so far. Is there a fuse somewhere else on the line, or just the fusebox?

I am getting a new battery soon. Gel or li-ion? Or should I stick with the same type?

What do I need to check on the bike? I was thinking of going from the engine alternator wires up the the battery, checking if it's even giving a charge and where it stops. Any known problem areas with these bikes as far as the charging goes? Can it be just a faulty battery? The previous owner did not ride it a lot and stood up to 6 months in a garage. He only did 3k kms in 2 years.

Thanks!

[Richard230]

Lately I have had issues with Chinese batteries bought during the past couple of years. They never seem to last and will not hold a charge for very long. But that was only during the covid years. The little lithium battery that I have had installed in my 2011 Bullet since 2012 is still having no problem getting my bike started using the electric starter and the bike's charging system seems to be able to keep it charged up while running.

As far as your problem goes, you should place a volt meter across the terminals of the battery and check the voltage while the engine is running. If you are seeing over 14 volts, but not over 15 volts (14.4 volts when revved up is typical), then your charging system is OK and your battery probably needs to be replaced.

[Gian4]

Hi
There are a few things I would check.  1) Check the battery wire connections.  They can become lose or even break due to vibration.  2) Check the fuses.  There is a fuse alternator connection is fused.  If that fuse blows it will not charge.  3)  Get a cheap voltmeter and check if you are charging.  There are plenty of videos on You Tube that show how.  It's quick and easy.    4)  It also could be your battery but I would check these things before buying a new one.  Hope this helps.
Gian4

[axman88]

If a single diode in the rectifier has failed, charging system power output can drop sufficiently to not keep up with the running loads, and the battery starts discharging.  I would check the rectifier regulator, (procedure attached).  Failure of the rectifier is not uncommon.

Because the rect/reg test is dependent on the presence of a good stator (and rotor) to give a good result, it's prudent to test the Stator if a bad result is gotten from the Rect/reg test.  I attached a jpeg with with procedure also.

It's not impossible for the rotor to lose magnetism and cause low output, but my impression is that this failure mode is less common.

As already suggested, probably the most common failure mode is simple loose connections, at connectors.  If I'm checking these, I'll disconnect, give them a shot of contact cleaner, then connect/disconnect a few times to clean off the oxide, then finally give a little smear of dielectric grease to keep corrosion out as I reconnect.    This stuff works well:   https://www.amazon.com/CRC-Plastic-Contact-Cleaner-Aerosol/dp/B000BXKZVA  Make sure to use one that is represented as compatible with plastic.  This stuff can also do a nice job of cleaning switches.
I use Permatex dielectric grease:  https://www.amazon.com/Permatex-81150-Dielectric-Tune-Up-Grease/dp/B000AL2RI2/ref=asc_df_B000AL2RI2/


If a battery is allowed to remain in a state of charge below 50%, it can lose capacity to sulfation, an irreversible, internal chemical process.   https://batteryuniversity.com/article/bu-804b-sulfation-and-how-to-prevent-it

Voltage tests to determine state of charge should be done at least 3 hours after riding or charging, otherwise a surface charge can remain, that will give false good results.  Finding a voltage of less than 12.2V on a Lead/Acid battery would have me looking for my charger.

There's lots to learn about batteries.  I recommend the online Battery University.   https://batteryuniversity.com/article/bu-201-how-does-the-lead-acid-battery-work.

I personally wouldn't go for a lithium option.  The charging system isn't really designed for Lithium and the amp-hour/dollar ratio is unfavorable, even considering a much longer promised service life, which may or may not be delivered.  AGM is worthwhile, in my opinion. 

I got three years out of the last cheap Sigmastek battery.  That's just $10/year.
https://batterysharks.com/yuasa-ytx16-bs-battery-replacement.html

  We'll see how the one I just put in my latest project lasts, it was even smaller and cheaper!

[zsiros]

Thanks for all the suggestions!

I will check everything tomorrow and return with the results. I have already ordered a gel battery, as this one has been discharged for a day now and I don't trust it anymore. I have to invest in a charger for such occasions. Given that the battery is 5 years old at this point, I hope it's just that.

[axman88]

Thanks for all the suggestions!

I will check everything tomorrow and return with the results. I have already ordered a gel battery, as this one has been discharged for a day now and I don't trust it anymore. I have to invest in a charger for such occasions. Given that the battery is 5 years old at this point, I hope it's just that.

Lots of folks in forums will state that 3 to 5 years is about all you can expect from a motorcycle battery.
   -  The batteries are small and don't have much reserve capacity,
   -  The charging systems are crude, prone to either starve for charge or overcook the battery, depending on your riding style, and the luck of the draw,
   -  The environment the batteries live in is hot and there's a lot of vibration, which isn't great for them structurally, and
   -  A lot of bikes spend a lot of time sitting patiently, waiting for their riders, which isn't good for a battery, because it goes downhill if not kept charged.   Lead / Acid self discharges, it's just the nature of the chemistry.

There are dumb chargers, which will obediently do as they are told, but overcook a battery if you aren't careful.
There are trickle chargers, which will do the same thing, only slower.
There are smart chargers, which are great for batteries in good condition, but can refuse to charge serviceable batteries once they start to go down hill.
And there are battery maintainers, which are smart chargers with a "Float Charge" feature that allows them to remain connected without overcharging.  Some also have a "desulfate" setting, but I'm not sure how, or IF that works.

Max charge rate should be 1/10 to no more than 1/5 of the rated amp hour capacity of the battery.  That's 1.2 to max 2.4 amps of charging current for a battery rated at 12 amp-hours.  Charging at too high a rate can tear a battery apart, internally.

[zsiros]

Correct me if I am wrong, but it seems like a faulty battery. I measured the voltage after I replaced it with a new one. Here are the voltage numbers:

• Bike off: 12.63V
• Ignition/headlights on: 12.32V
• Bike running at idle: 12.44V
• Rpm at around 2000: 12.54V - no photo as I ran out of hands to use

I did not try to keep it at 3000 rpm as per the photo as I have an AEW Goldstar exhaust and live in an apartment. While it has a good sound, no sound is good if it wakes you up.

Are these numbers okay? Thanks for all the help!

[Haggis]

Your voltage should rise to around 14 volts when you rev up the engine.
You dont need to hold it at higher revs, the voltage should rise quickly.
Yours are not.
You need to check out your charging system.
Probably your R/R that has packed in.
There are checks you can do on the alternator output as well.
Small video of my charging voltage today.
https://youtu.be/HZnwuxKs-Ck

[zsiros]

Your voltage should rise to around 14 volts when you rev up the engine.
You dont need to hold it at higher revs, the voltage should rise quickly.
Yours are not.
You need to check out your charging system.
Probably your R/R that has packed in.
There are checks you can do on the alternator output as well.
Small video of my charging voltage today.
https://youtu.be/HZnwuxKs-Ck

I'll check it, thanks!

[axman88]

I agree with Haggis.  Your measurements (assuming you left the headlight ON when the engine was running) suggest that the charging system is contributing, but only a little.  My guess would be that a diode in the rectifier has opened up, but there could also be a (less likely) issue with the stator, or even with the rotor.  Years ago, we used to be able to test, (but not neccessarily replace), individual diodes in rectifiers, but once manufacturers started packaging regulators in the same module, that ability was gone.

I'd verify the resistance of the windings, and do the checks of the stator AC voltage so I knew how far upstream the fault was.

It can take a while to get spares from India.  The good news is that all the parts are reasonably priced.  Or, if you aren't on a budget, quality and service from Hitchcocks is excellent.

[zsiros]

The weather finally cleared up, and I got a chance to get some measurements off the bike. What I measured was the cable that is coming from the alternator and attaches to the regulator. Started the bike and got tried all the combinations, here are the readings:

• 3.52V
• 4.27V
• 0.25V

Are these measurements right? Attached are the pictures of the readings and one picture of how and where I get these, to be sure that I have measured in the right spot.

[zsiros]

I also measured for continuity from the connector to the ground, I got no reading and measured for continuity on the regulator part of the connector where I get the measurements of the attached pictures.

Are these signs pointing at a fault in the alternator? Anything else I should check?

[Haggis]

The three yellow wires put out AC .
You are trying to measure DC.
Disconect the connector and measure in AC between any of the three pairs of yellow.
You should see a fairly high voltage, like over 20v ac.
You need to disconect the R/R and then measure from the five wires, 3 yellow, red, black,  the diodes for forward and reverse function.
There are loads on YouTube showing how to do this.

[zsiros]

The three yellow wires put out AC .
You are trying to measure DC.
Disconect the connector and measure in AC between any of the three pairs of yellow.
You should see a fairly high voltage, like over 20v ac.
You need to disconect the R/R and then measure from the five wires, 3 yellow, red, black,  the diodes for forward and reverse function.
There are loads on YouTube showing how to do this.

Ah, you live you learn. Thank you, will measure again. Found the videos, did not know I was trying to do it on the wrong connector, which explains why there were not enough cables.

[zsiros]

Re-did the measurements; this time I did it right. The AC voltage from the alternator is okay and is 20V+ on each combination at idle, rising to 40-50V when I rev the bike. The regulator is all over the place, measured with the diode tester. With positive bias (negative multi m. to the positive regulator) 1 of 3 did not give any measurement. Turned it around to measure negative bias and I got readings, as far as I am aware, there should be none, right? With the negative regulator cable + positive multi m cable. I got no readings on 2 of them, and the negative bias was all over the place.

Is it safe to say it's the regulator at this point, or must I dig deeper? Could anyone point me to the right regulator, or should I check the part number? Does Hitchcocks supply the part as well?

Thanks!