Topic: '76 550K Charging Circuit Troubles

[Dmitry]

Looking for hints on where to dig from here.

Here's the story. The bike drains the battery very fast. I measured the voltage on/current off the battery and here are the results:

RPMs   Volts   Amps
1200   11.9   -5.0   
2000   12.0   -3.0   
3000   12.3    0.5   
4000   13.0    2.0   
5000   14.4    3.0   
6000   14.5    3.5   
7000   14.5      

Conditions: high beam off. I also have numbers for high beam on and taillight on. Of course, the bike drains the battery even worse then.
Also: Before starting the engine:
Ignition off: 12.7V and 0A
Ignition on: 11.8V and -8.68A

I understand that draining more than 8 amps of current out of the battery for the headlamp and taillamp is way too much. I don't know where the power is lost.

Also, to check the alternator, I measured resistance between wires:

field coil (white and green wires): 4.8Ohm (within spec)
stator coil (3 yellow wires): 1.3Ohm (spec is 0.35Ohm)

While the stator coil values are way above the spec, the repair manual advises to replace the stator coil when they are below the spec.

Anyway, this is all I've got so far... Any help will be appreciated.

Dmitry

PS Attaching a spreadsheet with all the numbers

[Danno]

Dimitry those numbers tell me that either your mechanical regulator is off (I seriously doubt it if it worked previously) or the battery you have is past its life

you should have higher numbers than that with the headlight off so I would say the battery voltage is too low to start with get a new battery because either the one you have if new is defective or it is just plain too worn out to work

if you have  a desulfinator battery charger you could try that first and see if you can get the battery to hold a charge should be close to 12.8 or better on a freshly charged battery

[Dmitry]

Dimitry those numbers tell me that either your mechanical regulator is off (I seriously doubt it if it worked previously) or the battery you have is past its life

What is a mechincal regulator? The voltage regulator? How can I troubleshoot it?
The bike has been running all December and January.

you should have higher numbers than that with the headlight off so I would say the battery voltage is too low to start with get a new battery because either the one you have if new is defective or it is just plain too worn out to work

This battery is new. I replaced it because the old one was the one that came with the bike when I bought it in November and by the end of January the bike drained it, and I noticed one of the cells had no electrolyte.

if you have  a desulfinator battery charger you could try that first and see if you can get the battery to hold a charge should be close to 12.8 or better on a freshly charged battery

I have a 2 Amp trickle charger, that's what I used to charge the battery after the bike drained it last time.
Also, a note: after running the tests the voltage on the battery dropped from 12.75V to about 12.4V. I did start the bike with a starter and that's what I thought has drained the battery.

PS. I am attaching an excel file with all the numbers to the head post.

[Danno]

Dimitri your battery with a 2 amp trickle charger can only be charged for a maximum of 6 hrs anything longer like over night will cook it and in most cases when it is only low it can't handle more than 2 hrs of charging it is only a 12 amp hour battery stock

as i said the regulator is probably not the problem however there are instructions for cleaning and adjusting here on the sight
and to be totally honest if you do not know what it looks like get a manual and learn about it before you tamper with it
the regulator is adjusted by bending the contact wing and there is also a screw tiny adjustments can make big changes changes that could burn up your battery or make it not charge at all

if you got the battery from wall mart take it back as defective and buy one from TSC the walmart batteries are all junk and the batteries from tsc and the ones you get from a dealler and even batteries plus are better

I have gone through this too Dimitri and I am telling you it is much more likely to be the battery  and the ground wires from the battery to the frame

[Danno]

Dimitry if you check and replace the grounds and use a fresh battery and test it again report back what you find and I will dig up the documentation for the regulator and try to help you or you could send it to me and I will fix it here and send it back but replace the grounds  and make sure the battery is charged before you do the test I am going to bed now so I will look for your response tomarrow

[TwoTired]

you are doing the right things. You just need to continue.
You could tell us more about the bike, like electrical mods, coils/ignition perhaps? Or if it is in stock configuration.

The stator can be tricky to measure accurately and like motorcycles there are variations among models.  Tell us or show us your test tool specifics.
It may be that your meter leads have resistance that the meter can measure, so you have to subtract that out from the meter reading.  What is displayed if you simply touch the lead tips together?

The stock 550 usually draws about 10amps with the key switch and low beam on.
And the alternator makes about 1/3 of max output at idle speed, and it only makes about 150 Watts (12.5 A) at 500 RPM.  That power is distributed to what the bike uses with any extra going to recharge the battery.

If the bike loads are still stock, then I would check the six diodes in the rectifier for proper function. Using a meter with a diode test function, and the rectifier disconnected from the bike measure from each yellow to green, then do that again with the meter probes reversed.  You should see a low ohm reading with one polarity and a high ohm reading with the opposite polarity.  Repeat the above procedure for the yellow(s) to red wires.  In the end you will have twelve reading and half will be low and the other half high.  If you are uncertain, report your reading to us.

If the rectifier checks good and you have verified the connection between alternator and rectifier are intact, then check to see if the Vreg is getting correct battery status info,  Compare what the voltage is at the battery to what is present across the Vreg's Black and green terminals (turn the headlight back on for this test).

Finally, it's certainly nice to have the battery load tested, as you can't really do a proper troubleshoot of the charging system without a known good battery.

Pardon any typos or grammar errors.  (Too lazy to proofread what is essentially a rehash of a couple dozen prior posts on this very same topic.)

Cheers,

[orange550]

Probably not your issue... but I had similar problem on my 550; new battery, great voltage output at rpms, but the battery still died. I kept going over the wiring..wiggle the battery terminals, etc. All seemed fine. Then I finally put a wrench on one of the battery terminals, and it was a tiny bit loose. (a little more than hand tight) I pulled it off, did another little clean with emery paper, and tightened it up. Worked great afterward.

I was very surprised it was somehow not allowing the battery to charge since it seemed clean and was making full contact.

[Bodi]

Where are you measuring the stator coil resistances? It's rather unlikely that its resistance went up, possibly your meter doesn't do low resistance well (most have this problem). TT's suggestion to measure the "zero" resistance with the leads touched and then subtracting that reading is excellent. Also, there are probably some connections involved unless you measure the stator coil at its attached leads: these generally connect to other wires using bullets under the engine cover. Many charging problems are due to old corroded connectors which eventually get hot and then get really bad. If you find blackened or charred connector cover sleeves or brittle discolored wires near a connector, that connector is toast and can not be rejuvenated since the metal will have lost its "spring". Usually soldering and insulating the wires at the connectors under the engine cover is best - all 5 wires from the stator and field coils. The engine plug uses 1/4" spade inserts that can be replaced if they have overheated. These should be crimped and soldered: the crimp will hold the wire in even if it overheats enough to melt the solder and the solder provides a corrosion resistant connection.

[Dmitry]

you are doing the right things. You just need to continue.
You could tell us more about the bike, like electrical mods, coils/ignition perhaps? Or if it is in stock configuration.

The bike is pretty much stock. The only mod to the electrical is that the blinker beeper was removed.

The stator can be tricky to measure accurately and like motorcycles there are variations among models.  Tell us or show us your test tool specifics.
It may be that your meter leads have resistance that the meter can measure, so you have to subtract that out from the meter reading.  What is displayed if you simply touch the lead tips together?

Good call. The resistance between test leads is about 0.3-0.4 Ohms. Since I was measuring the resistance between the yellow wires coming out of the 3x3 plug, there must be some resistance in the wires going from the plug to the stator coil.

The stock 550 usually draws about 10amps with the key switch and low beam on.
And the alternator makes about 1/3 of max output at idle speed, and it only makes about 150 Watts (12.5 A) at 500 RPM.  That power is distributed to what the bike uses with any extra going to recharge the battery.

So, mine draws about 9 amps with the key switch and low beam on, but at 1200rpm (its idle), it's still pulling 5amps out of the battery : (

If the bike loads are still stock, then I would check the six diodes in the rectifier for proper function. Using a meter with a diode test function, and the rectifier disconnected from the bike measure from each yellow to green, then do that again with the meter probes reversed.  You should see a low ohm reading with one polarity and a high ohm reading with the opposite polarity.  Repeat the above procedure for the yellow(s) to red wires.  In the end you will have twelve reading and half will be low and the other half high.  If you are uncertain, report your reading to us.

My meter has a diode symbol at the 2kOhm range resistance measuring mode. I used that. Below are the results for the rectifier:

From yellows to green: OC
From green to yellows: 0.5kOhm

From red to yellows: OC
From right yellow to red: 0.5kOhm
From 2 other yellows to red: OC

So, it looks like there is a problem with the rectifier.

If the rectifier checks good and you have verified the connection between alternator and rectifier are intact, then check to see if the Vreg is getting correct battery status info,  Compare what the voltage is at the battery to what is present across the Vreg's Black and green terminals (turn the headlight back on for this test).

The connections between the 3by3 socket and the rectifier socket (3by2) show continuity.

Finally, it's certainly nice to have the battery load tested, as you can't really do a proper troubleshoot of the charging system without a known good battery.

How do I test the battery load?

Thank you so much for the advice.
To give you more information on the condition of the bike, I took some pictures. They are attached to the post.

Where are you measuring the stator coil resistances? It's rather unlikely that its resistance went up, possibly your meter doesn't do low resistance well (most have this problem). TT's suggestion to measure the "zero" resistance with the leads touched and then subtracting that reading is excellent. Also, there are probably some connections involved unless you measure the stator coil at its attached leads: these generally connect to other wires using bullets under the engine cover. Many charging problems are due to old corroded connectors which eventually get hot and then get really bad. If you find blackened or charred connector cover sleeves or brittle discolored wires near a connector, that connector is toast and can not be rejuvenated since the metal will have lost its "spring". Usually soldering and insulating the wires at the connectors under the engine cover is best - all 5 wires from the stator and field coils. The engine plug uses 1/4" spade inserts that can be replaced if they have overheated. These should be crimped and soldered: the crimp will hold the wire in even if it overheats enough to melt the solder and the solder provides a corrosion resistant connection.

I was measuring the coil resistances on the 3by3 plug. I'm pretty sure my $12 multimeter isn't great at measuring resistances either. So, we can disregard those values.

I will look for bad connectors and will try to replace them when I have time. Right now I hardly even have any time to spend with the bike on weekends...

Since many of you recommended checking if the ground connections are good, where do I look for those?

Thank you,

Dmitry

[Dmitry]

More pictures

[TwoTired]

The bike is pretty much stock. The only mod to the electrical is that the blinker beeper was removed.

I can accept that.  But, I have been fooled by replacement headlights that look the same but were of a higher wattage.  Could it have been changed by a PO?  Did you check the bulb markings.  Given your other responses (addressed later), no real need to worry about this now.

The resistance between test leads is about 0.3-0.4 Ohms. Since I was measuring the resistance between the yellow wires coming out of the 3x3 plug, there must be some resistance in the wires going from the plug to the stator coil.

Won't hurt to clean or renew the connections to minimize power loss.  You might find corrosion that can become a problem further down the road (and usually on a trip of some sort).

So, mine draws about 9 amps with the key switch and low beam on, but at 1200rpm (its idle), it's still pulling 5amps out of the battery : ( 

Pretty much normal loading for a low battery.  A good battery should allow this for about an hour.  But, Honda expected the engine to be revved above that while riding, which would normally restore battery charge state.

My meter has a diode symbol at the 2kOhm range resistance measuring mode. I used that. Below are the results for the rectifier:

From yellows to green: OC
From green to yellows: 0.5kOhm

From red to yellows: OC
From right yellow to red: 0.5kOhm
From 2 other yellows to red: OC

So, it looks like there is a problem with the rectifier.

Yes, looks like two bad diodes in the rectifier.  This would reduce your charge capability about 2/6ths or 33% across all RPMs, and really hinders battery state restore on a 550.

If the rectifier checks good and you have verified the connection between alternator and rectifier are intact, then check to see if the Vreg is getting correct battery status info,  Compare what the voltage is at the battery to what is present across the Vreg's Black and green terminals (turn the headlight back on for this test).

The connections between the 3by3 socket and the rectifier socket (3by2) show continuity.

Simple continuity is not accurate enough for this purpose.  The test was only required if the rectifier checked good.  It didn't, and you found a smoking gun.  It's possible that it's not the only one, though.  But, after you get the rectifier restored, you can check if the wire connectors and switches are operating efficiently, by measuring the voltage reaching the Vreg from the battery and see if there is loss.  Let's say you measure 12.4 V at the battery and 11.4 at the Vreg terminals.  This causes two problems.  One, the Vreg is being lied to about the battery true charge state.  And two, this is the power that the vreg passes to the alternator to determine it maximum strength output.  Reduce the voltage or power to the alternator and the alternator cannot make its full rated power output.  It can only multiply upon the power it receives.

How do I test the battery load?

With a battery load tester.
http://www.harborfreight.com/100-amp-6-volt-12-volt-battery-load-tester-90636.html

However, the shop that sold you the battery should have one and test it for free.  I'd fix the rectifier first and decide about that if problems persist.

Cheers,

[Spanner 1]

Excuse me Dmitry but those connectors in pic. 1 and 2 above are CRAP.. Please shine those spades and their opposite receivers before you do anything else..... could easily cause charging problems in my experience....... no good ( required ) connection in those blocks  . These connectors should always be the first thing scrutinised when charging probs. suspected 

[seanbarney41]

If the rectifier checks good and you have verified the connection between alternator and rectifier are intact, then check to see if the Vreg is getting correct battery status info,  Compare what the voltage is at the battery to what is present across the Vreg's Black and green terminals (turn the headlight back on for this test).

TwoTired(or anyone else that knows the answer), I'm going through the same thing with a '76 cb550k.  What does it tell me if I'm measuring 12volts at the battery and between 10-11volts at the green and black terminals of the v-reg? (with engine idling, headlight on)  ...just that I have a bad contact/connection somewhere?

[Dmitry]

I ordered part #R255a-H from here: http://www.oregonmotorcycleparts.com/rectifiers3p.html
Hope it'll get here some time next week. Also, planning to clean out those connector plugs and sockets tonight (buying a metal brush for that).
Also, will measure the voltage on Vreg.

Will report on the progress once I install the new rectifier.

[TwoTired]

If the rectifier checks good and you have verified the connection between alternator and rectifier are intact, then check to see if the Vreg is getting correct battery status info,  Compare what the voltage is at the battery to what is present across the Vreg's Black and green terminals (turn the headlight back on for this test).

TwoTired(or anyone else that knows the answer), I'm going through the same thing with a '76 cb550k.  What does it tell me if I'm measuring 12volts at the battery and between 10-11volts at the green and black terminals of the v-reg? (with engine idling, headlight on)  ...just that I have a bad contact/connection somewhere?

Yes.  Either the circuit path from Battery POS to black has excessive loss, or the circuit path from battery Neg to green has excessive loss, or a combination in either pathways.
The wires aren't a problem in these occurrences usually.  However, connectors, crimps, switch contacts, and fuse contacts can be.  Incidentally, the V drop will likely be worse with high beam activated. Passing current through resistive element causes voltage loss through the resistive pathway.  More current increases V loss.  Degraded connectors, Switch contacts, etc. exhibit higher resistance, through surface oxides, poor contact pressure, and reduced contact area.  Contacts that are clean, tight, and wide offer the lowest resistance.

Cheers,

[Spanner 1]

Seanb...  clean all your connectors, esp. in the h/l bucket AND the fuses.' Looks O.K.' doesn't cut it with electrical stuff. Shiny is good everywhere there is a connection in the wiring. Do it once and be electrical fail troublefree for years .... just don't ever put your bike thru' a car h.p. car spray wash, the cause of failed electrical on lots of SOHC's IMHO. The electrical on these bikes was never intended to be soaked and would cause failures many months/years later. I think you looking at it a few posts up (pics. ) in this thread....... good luck!
High pressure water+chemicals never need to be directed at a bike, goes where it never was intended to be....... but seems to be done regularly by some owners...baah.

[seanbarney41]

...already working on it ...and seeing improvement...thanks guys

[Dmitry]

Letting everyone know on the progress since the last time I wrote here.

I got the new rectifier. The voltage on/current to the battery numbers improved, of course, but not quite to the level i'd like them to.

I didn't do a full-on test of current and voltage at all rpm's at with low and high beams, but with the low beams, the bike starts charging the battery at around 2000 rpms, and of course at even higher ones if the break light is on. So, since the bike is my everyday commute, this is not acceptable.

I started by assuming that the alternator is ok (the resistances on the three yellow wires). Next up was the field coil - I tested it by measuring the resistance between the connections on the Vreg - white/black (+ terminal of the battery) showed 4.8 Ohms, white/green (ground) showed 4.3Ohms. If I'm not mistaken, the these numbers should be within 10% of 4.8 Ohms, which they roughly are.

Next up was making sure that the Vreg is getting the right voltage on the battery. This is where it gets interesting.
First, with a battery disconnected, but the key on, I measured the resistance between the green wire and the battery minus and got 0.7Ohm. Then, the resistance between the black wire and the battery plus terminal - same result. Given the "embedded" resistance of 0.3Ohm of my multimeter, these values are quite good and should not cause a voltage drop given the wire isn't load-bearing.

Next, I connected the battery, key on, and measured the voltage on the Vreg - it was 11.6V vs 12.7V on the battery! So, one volt was lost on the way, and I need to figure out where. I found this wiring diagram for the CB550, and marked the connections I need to examine. The diagram is attached.

I took out the whole electrical board with the Vreg, rectifier and flasher, etc, and brought it home. I will write an update here within the next couple of days to report on the progress.

[TwoTired]

You did the right things.

Finding the 1 v lost is the next thing to address.  Almost certainly you 'll find the voltage lost by the pathway connection, the key switch, and/or the fuse clips, or all of the above.

You didn't say if you had the headlight on during the v loss test.  But if not, your voltage loss will be more when the lights are on.  This is because v loss is greater when higher current s flow through resistive elements.

Also, you are supposed to check the charging system with a known good, fully charged battery.  If the battery is undercharged, it will hold all the voltages low until it gets full.

Cheers,