Topic: CB550 not charging

[Leo_King]

Hello guys,

I have a problem with my charging system as the voltage of the battery does not change or only a tiny bit when I rev the bike up. I saw there are already a few post on CB550s with MUnits and Lithium batteries, but I think they have had different issues. Maybe someone here has some experience with a similar issue or sees what I have missed :-).


First of all, here the facts on the bike:

• 1976 CB550 K withe CB550 F Motor
• MUnit with Lithium Ion Battery and lithium ion capable Regulator Rectifier

The wiring of the bike seems ok as all the other components are working right from what I see so far.
Here a small sketch:


Here what I figured out or tried on the charging system:

- Battery voltage is at 12.5 V and does not really change when I rev up
- The resistance between the three stator phase wires (yellow) is 3.3 Ohm, according to manual it should be 0.35 Ohm what does not seem optimal.
- The three phase wires are not shorted to ground
- The field coil wires (light blue and green) have a resistance of 4.3 Ohm (4.9 Ohm +/- 10% according to manual)

The stator phase resistance seems not to be optimal, but before I get a new one I wanted to make sure the rest is ok.

- I measured the field coil output of the regulator (white wire coming from RR) and it has always +0.6 V, which I wonder might be too little maybe.

- To test, I disconnected the white wire from the RR, which what I understood controles the charging output via the field coil and directly connected the field coil (light blue) to the ignition plus hoping that the charging output of the stator should be at max. Then I started the bike: The battery voltage ramped up to 13.1 V depending on the motor speed. So this seemed to have some influence on the charging.

Now I am wondering if the output signal from the RR to the field coil is too low or maybe that he does not have a good source to measure the ref. voltage of the bike.

Does anybody know how much voltage the RR on a regular 550 gives out, as my 0.6 V seem to be low though. And what do you guys think about the high stator phase Resistance of 3.3 Ohm, maybe some of the charging power is lost due to its high resistance I am thinking.

Thanks a lot in advance! I hope I did not overlook similar posts.

[calj737]

The mUnit has nothing to do with the charging side of your bike. Your issue is with the wiring of the stator or to the R/R. A couple of decent close-up pictures of your wiring to the R/R, to the chases grounds, and to the battery will be appreciated.

[bryanj]

Did you short the tester wires together before masurements and deduct that reading from measured reading? All meter unless very expensive are bad at reading very low ohms.
Normal charging fault with standard parts is bad connections to field or stator OR the sense wire at the regulator not getting full battery voltage due to switch/connector resistances

[Leo_King]

The mUnit has nothing to do with the charging side of your bike. Your issue is with the wiring of the stator or to the R/R. A couple of decent close-up pictures of your wiring to the R/R, to the chases grounds, and to the battery will be appreciated.

Hi,
I hope this helps a little. I had all wires from the alternator to the RR in one plug, but to make sure there are good connections, I rewired them and to diagnose easier I also separated the phases and the coil wires.

The common ground is also used by other components and should be ok same for battery minus.

[Leo_King]

Did you short the tester wires together before masurements and deduct that reading from measured reading? All meter unless very expensive are bad at reading very low ohms.
Normal charging fault with standard parts is bad connections to field or stator OR the sense wire at the regulator not getting full battery voltage due to switch/connector resistances

Yes, it was only 0.1 Ohm. What do you think about the high resistance of the stator phases?

And do you know what voltage a regulär 550 regulator would output to the field coil?

[calj737]

Your stator can produce up to 17 volts with no regulation. From the regulator, you need a wire connected to a reference voltage of the battery. I have used mUnit AUX for that. That should read exactly the battery voltage directly once the mUnit is excited.

[bryanj]

I have never had a stator go back unless physically damaged, the regulator should put full battery voltage to the field if battery low and with stator yellow wires disconnected you should get 60 v ac between each of the 3 pairs when reved

[scottly]

- I measured the field coil output of the regulator (white wire coming from RR) and it has always +0.6 V, which I wonder might be too little maybe.

This is your problem! The voltage from the regulator to the white field wire should be close to the battery voltage: at only 0.6V, the field coil can't magnetize the rotor, and no charging can happen. The reg needs to have +12 volts applied to the black wire. If there is +12 V on the black wire, but only .6V coming out, the regulator is faulty.

[Leo_King]

Hello Scottly,
great to know that the field coil voltage should be around 12V.
Thank you!

[bryanj]

Is this a combined reg rec or the original system?

[Leo_King]

Is this a combined reg rec or the original system?

A combined unit.

[bryanj]

Thrs your problem, the electronic units arefinicky and sensitive especially to bad connections and incorrect voltage

[calj737]

Thrs your problem, the electronic units arefinicky and sensitive especially to bad connections and incorrect voltage

That's about stupid. Simply because something is new, and not stock does not make it a "problem". He has a wiring issue, not a component issue. Thousands upon thousands of bikes of this era have had their charging components upgraded with 100% success. And had you read his original post, you would already know the answer to your question.

[bryanj]

And i have seen more blown combined units than i can remember, like i said it takes a fraction of a second of bad or incorrect wiring to blow them plus most are made from inferior quality parts in china, there are a few reputable sellers but not many and they are usually the expensive ones.
Even majour bike manufacturers had problems with combined reg rec, ask a Yamaha dealer about the 4 or 5 mods to xs 760 when they first came out

[calj737]

Yeah, let’s dial the calendar back 30+ years and ask about new tech THEN versus proven tech now. What a Luddite attitude.

[Deltarider]

Yeah, let’s dial the calendar back 30+ years and ask about new tech THEN versus proven tech now. What a Luddite attitude.

Led is also a new technique. Here is why I abstain from using them: they are also - in Bryan's words - "finicky and sensitive especially to bad connections".

[bryanj]

Not a Luddite, and they came from my home town, just realistic after 50 years in the engineering trade.
Some electronics are supremely reliable but others totally oposite.
Led hose lights are now the norm but you still get some last only days or start to flicker anoyingly after a relatively short time whilst others last for years with no problems, and they can be from the same batch.
A motorcyle is an inherantly harsh and vibratory existance for everthing especialy electrics

[jaytee-nz]

And let's face it - 95% of reg/recs are made in China now. They're still figuring out what "quality" means unfortunately.

[Deltarider]

And let's face it - 95% of reg/recs are made in China now. They're still figuring out what "quality" means unfortunately.

Just calculate for yourself how likely it is, forced labour/slavery will result in good and reliable consumer goods.

[HondaMan]

Just calculate for yourself how likely it is, forced labour/slavery will result in good and reliable consumer goods.

There's the ACTUAL problem...

Speaking to Chinko-manufactured semiconductors expressly: I have sent back entire batches of Chinese-made semiconductors like transistors, diodes, and integrated circuits, because they either didn't meet specs or varied so widely from one part to the next that they couldn't be relied on to actually work in the circuit/machine/product I was building. The Chinese actually do not care about quality, just sales.