Odd Charging Question

G'day Vince. Your strange voltage readings could just be a result of the mysterious inner workings of the RR.

The alternator itself is uncontrolled. It works flat out all the time, making as much power as it can at whatever revs it's doing. The RR converts the alternator's AC output to DC then decides what to do with it. It can either feed it into the bike's wiring harness (to power various devices and charge the battery), dump it to earth, or send a bit each way depending on how the system voltage is looking. It does a bunch of internal switching to accomplish that control function. Switching your lights on may take the RR over a threshold level where it needs to send more power to the wiring system rather than dumping it. The result could be a slight increase in voltage.

Disclaimer: The above 'explanation' is little more than educated guesswork. Electronic control systems is not a subject I'm particularly clever at, nor is it something I'm keen to learn about. Someone with a better grasp than me of the inner workings of solid-state voltage regulators may have more coherent explanation.
 
Vince said:
Next time I might feel how hot the battery is getting if I see those readings again.
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Have a feel of how hot the regulator is getting too. I would have been happy with those readings you got now. It does seem odd to get a high voltage reading on your ride though, and a bit worrying.
 
I am surprised and happy with those numbers, don't know why its different in the shed from late yesterday's expressway readings. Yep will feel the battery and regulator for excessive heat if I see 15 volts again.
 
As usual, Cam makes a lot of sense. I don’t really know how the RR works either, but that sounds plausible to me.
Also good to know your cheap gauge is about right. AND the extra switch for the third phase must be already bypassed, as per Piets strong advice 👍.
Might be good to keep an eye on, to see what happens in different circumstances, like cold weather, old battery, etc etc.
On the other hand... it’s another thing to worry about 😉 .... 15v charge isn’t really a problem.
 
Vince - something is amiss with your charging system. In good fettle, measuring voltage at battery terminals, I would expect 14.3-14.5v with engine running (noting that you have a Redax system fitted which will cope with the 90/130 headlight). Readings you provided indicate that the system is not providing sufficient output. 12.8v is what a fully charged battery in good condition will measure.

I'd check your reg/rect wiring carefully for poor connections, substitute a known good reg/rect or do a full fault find.
https://www.laverdaforum.com/xf/resources/18/
 
CLEMTOG said:
my Mercedes E class has been telling me that I need new brake pads (it doesnt) and that light comes on every time I start it, and I clear it, without even thinking, then nothing until the next start, and yes the computer has been "cleared" it has already cost me a monkey and a tin barf, and they "think" its a wiring fault, the first time it came on, it didnt even then need new pads, but the discs (4) and pads have since been done anyway, fault light remains, a few years ago an orange light came on VISIT WORKSHOP, so I did ,and they said its a N/S/R wheel speed sensor, total bill to change out, a wheel off then push in with the fingers item was £250.00, the item was £26.00, but it didn't clear the light, I had to pay the money to be allowed to take the car away, a much smaller independant "any make" village garage fixed it for free, it was a corroded electrical male/female plug on the N/S/F wheel, unplugged, cleaned Dow Corning electrical greased and plugged back in, they did all four corners including the new one and said that it hadn't been changed, but had clearly been on and off.
CLEM
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Bit off topic Clem, but I had the same issue with a W210 E Class Mercedes. The fault was in the wiring loom under the center console.
Mercedes quoted me an outrageous figure to diagnose and fix the fault, so I took it to an ex Mercedes dealership mechanic who knew where the problem was. Took him quite a while to strip down the center console and locate the breaks, which he soldered back together. 6 years later still holding up, although I sold the car a while back.

HTH
Gerald
 
I took the bike to western Laverda Central yesterday for a look see and a few issues were found where the dashboard Volt Gauge took its power supply from that might have caused some inconsistency with its readings. We were hoping that might fix the high readings. It's now extremely close to what showed on Bretts Multimeter at all operating situations. I headed home and on the expressway its showing 14.6 volts at 4000, turn low beam on and its 15.2 at the same revs. I have another Shindenco Regulator and will swop it in and see what happens. Hope that fixes it or at least changes the reading.
 
Are you SURE the headlight-extra-phase-switch-thing has been bypassed?
Low readings have many possible causes... but the only reason for a high reading is a high value!
 
Brett seems to think that Headlight thing is ok, but its worth some looksee I am hoping the Regulator is the issue. Will know more soon.
 
I have a spare Marty, will fit it sometime this week and check the readings. I do know all 3 yellow wires from the alternator go directly into the regulator, if that says anything about Andy's point referring to the headlight-extra-phase-switch-thing has been bypassed?
 
This thing about re-routing all three wires directly to the rectifier begs the question why the designers thought to wire one phase through the headlight. Must have been a good reason to do it that way; maybe to reduce the load on the rectifier?
 
Legs said:
This thing about re-routing all three wires directly to the rectifier begs the question why the designers thought to wire one phase through the headlight. Must have been a good reason to do it that way; maybe to reduce the load on the rectifier?
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Yes. It would reduce the amount of current the regulator would have to shunt to earth, and the RR would run a bit cooler.
Also reduces the power input from the shaft that drives the alternator (crankshaft) so you'd have an extra 0.1 HP available to pull wheelies with.
 
That's what I thought. I ran all three wires directly to the rectumfryer for a while as recommended, then had a little think about it and tried digging up all the electrical theory I learnt fifty years ago; one thing I learnt (and retained) is not to overload circuitry.
 
So does that mean there shouldn't be 3 yellow wires running into my Regulator from my Kawasaki Alternator? I haven't fitted the other Regulator yet to test it, Medical stuff this morning and to wet and dark in my shed now.
 
Not sure Vince but you could run the bike on the stand and check the voltage across the battery. Mine reads a healthy 14.5V (ish) at medium revs with lights off.
 
It's a personal choice. The alternator runs at its full capacity all the time, but provided your RR is rated for the full output of the alternator, it'll cope OK with all 3 phases permanently connected. There's no technical reason why you'd need to control the output from the alternator, but you can certainly choose to if you want to, by reinstating the phase isolating relay operated by the headlight circuit.

As mentioned above, it would likely make the RR run a wee bit cooler, which might be useful if it's in an area that doesn't get much air flow. I don't think you'll notice the miniscule power gain at the crankshaft though.

I think the reason they did it that way on the early Laverdas was because they only had a rectifier (with no regulator function) so it was a form of partial voltage regulation. The other part of the voltage control was achieved by having a massive battery that wasn't fazed by alternator output.
See what I did there - phased, fazed ... OK, it's a lousy pun.
 
Both Regulators I have were supplied by John Wilson when he fitted the Kawasaki Alternator to my bike when he lived in Bowral. There Shindenco, whatever model made for the Kawasaki 250 the alternator came off so they should handle what's turned out by this system. Hopefully this weather doesn't turn into an East Coast Low and I can see how the other one works out, but it looks like it will.
 
Not only the early Laverdas, my RGS has the same set-up.
Guess whatever floats your boat, I've tried both configurations without any noticeable difference so decided to return to standard.
 
The switching of the third phase is redundant if you use your headlight all the time, because it only ever turned on when the headlight is on and supplied the extra ergs required.
But although it’s not required, it can still cause faults which can leave you stranded...
 
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