[TheBogieMan]

A voltage regulator regulates the charging voltage that the alternator produces, keeping it between 13.5 and 14.5 volts to protect the electrical components throughout the vehicle. The major advantage of an alternator (AC) found on modern bikes and cars over a Dynamo (DC) as found on older stuff, is that it is a three phase unit as compared to a dynamo a single phase unit. An alternator will give a much higher charge rate at slow speeds (idle) since on one rotation of the pulley will cut through 3 magnetic flux fields instead of just one.
To convert this alternating current to direct current is done by using a series of 6 diodes that are mounted in a rectifier assembly. A diode allows current to flow only in one direction. If voltage tries to flow in the other direction, it is blocked. The six diodes are arranged so that all the voltage coming from the alternator is aligned in one direction thereby converting AC current into DC current.
Dynamos have brushes so life will be shorter since all output current must go through the brushes. Only the field current (2/4 amps) will go through the alt brushes.
The voltage regulator on a dynamo is far more complicated then it is on an alternator. It has a cutout relay and a current limiter in addition to the single voltage limiter that you will find on both units.

If the rectifier dies it can kill off the regulator, if the reg dies then it can cook the battery.
Most bikes have them combined into one unit, some early pre 80's stuff has separate units

[The Mex]

Nice one Bogie....

Stickied now!!

[John Bulleteer]

TheBogieMan, on Jul 4 2008, 07:00 AM, said:

If the rectifier dies it can kill off the regulator, if the reg dies then it can cook the battery.
Most bikes have them combined into one unit, some early pre 80's stuff has separate units

My rectifier died a few months ago, the bike just stopped charging.
I got a "Power Box" fitted instead (By someone who knew what they were doing, not me).
This single box replaces both rectifier & regulator, which were two seperate units.
It says I can now run the bike without a battery.
My understanding is that the rectifier produces the charge & the regulator dumps off excess charge to stop it overcharging the battery.
So for example if you turn on your lights, the regulator just allows more charge out to feed the lights.
Im guessing the power box somehow manages to do this same job.
Its still all a dark art to me.
Bulleteer.

[TheBogieMan]

The excess charged will be dumped out as heat, hence the cooling fins on the unit, the Enfeild has a fairly low output alternator on it.

[KeepinHerLit]

Think my reg/rec is on the way out....

Problems im having:

After long spins (more than 2/3 hours) or after my headlights were changed, my bike won't start, Lights flicker and starter clicks but bike won't start.

After I charge battery, My bike starts fine... After a few long spins... Or a day or two sitting up the bike again tends to be hard to start or won't start at all.

Battery is newish, Got it in january!! Its an easystart one....

Put a multimeter on battery after I have charged it with my oxford oximiser and it reads fine (12v). Put battery in bike and turn bike on and it jumps very high.... Without reving it tends to sit at around 14v and jumped up to nearly 17v when I revved it. Which going by Hanyes manual is way too high....

After much hmming and hahing and chatting to ET about it and consulting my trusty Haynes manual it points to a dodgy Regulator... Does this sound right??

Hoping its a quick fix and I can just buy a new regulator and put it in

Anyone know the best place to get Suzuki parts?? Figure I might get it from wemoto.com but if theres a cheaper place direct me to it

[Lasse]

Actually a regulator doesn't limit the volts charged to the battery, it just allows the battery to be charged. As in, you don't see many regulator units having heatsinks etc.



As an example

Attached File(s)

•  6volt_regler_neu.jpg (15.39K)
  Number of downloads: 19

This post has been edited by Lasse: 31 March 2009 - 09:11 PM

[petecourtney]

Lasse, on Mar 31 2009, 10:10 PM, said:

Actually a regulator doesn't limit the volts charged to the battery, it just allows the battery to be charged. As in, you don't see many regulator units having heatsinks etc.



As an example

The regulator does limit the charging voltage. It's a voltage regulator.

<edit>The pic of the reg you posted is not your normal jap reg, it's German (is it off the MZ?)
They're very similar in operation to car alternator regulators, they sense the voltage going to the battery and switch off the magnetic field (electo-magnet) when the design voltage is reached. The low current involved in the field windings are the reason for no cooling fins etc... they don't switch the output of the alternator on and off directly. This set up uses seperate rectifier somewhere to convert the stator output to DC. Jap reg/recs are usually a combined unit, with the field being comprised of permanent magnet(s). In this set up the regulator switches the output on and off. So the current the regulator is switching is higher than in the MZ set up.</edit>

This post has been edited by petecourtney: 31 March 2009 - 09:27 PM

[Lasse]

petecourtney, on Mar 31 2009, 09:20 PM, said:

The regulator does limit the charging voltage. It's a voltage regulator.

<edit>The pic of the reg you posted is not your normal jap reg, it's German (is it off the MZ?)
They're very similar in operation to car alternator regulators, they sense the voltage going to the battery and switch off the magnetic field (electo-magnet) when the design voltage is reached. The low current involved in the field windings are the reason for no cooling fins etc... they don't switch the output of the alternator on and off directly. This set up uses seperate rectifier somewhere to convert the stator output to DC. Jap reg/recs are usually a combined unit, with the field being comprised of permanent magnet(s). In this set up the regulator switches the output on and off. So the current the regulator is switching is higher than in the MZ set up.</edit>

I wasn't referring to bike regulators, but more regulators in general I also have one from a boat where I have a screw that goes from 1-14v depending on what I need.

[petecourtney]

Lasse, on Mar 31 2009, 10:30 PM, said:

I wasn't referring to bike regulators, but more regulators in general I also have one from a boat where I have a screw that goes from 1-14v depending on what I need.

Understood... but the one in the pic... is it from an MZ? Put me out of my misery!!!

[Lasse]

It can be used on MZ's yes

[petecourtney]

KeepinHerLit, on Mar 31 2009, 10:05 PM, said:

Think my reg/rec is on the way out....

Problems im having:

After long spins (more than 2/3 hours) or after my headlights were changed, my bike won't start, Lights flicker and starter clicks but bike won't start.

After I charge battery, My bike starts fine... After a few long spins... Or a day or two sitting up the bike again tends to be hard to start or won't start at all.

Battery is newish, Got it in january!! Its an easystart one....

Put a multimeter on battery after I have charged it with my oxford oximiser and it reads fine (12v). Put battery in bike and turn bike on and it jumps very high.... Without reving it tends to sit at around 14v and jumped up to nearly 17v when I revved it. Which going by Hanyes manual is way too high....

After much hmming and hahing and chatting to ET about it and consulting my trusty Haynes manual it points to a dodgy Regulator... Does this sound right??

Hoping its a quick fix and I can just buy a new regulator and put it in

Working on the basis that there's no problem with the starter motor and associated wiring/components/connections etc, it sounds like your battery is either flat, or doesn't have the required capacity to turn your engine over. This could be down to the battery being faulty, or it not being charged for a long enough period. How long are you leaving it charging for? When the battery is fully charged it should read about 12.7~ Volts, is this the reading you're getting? You will get a reading of 12V off even a quite flat battery. James recently put up a comprehensive post on batteries, I think the thread was called "how batteries work" or similar. edit: james post here
Also see wiki here for battery voltage info.

With regard to your charging system, much more than 15 Volts would be too high in my opinion (Haynes should give you the spec for your bikes). A reading of 17 Volts suggests to me that your regulator is faulty.
Over-charging will 'boil' off the electrolyte in a lead-acid battery, diminishing it's capacity to provide it's designed output (i don't know if this is also true for gel type batteries). I have had this problem with Honda's in the past, and the symptoms are very much what you've describe above: bench-charge battery, it works fine for a couple of days... then bike fails to start... repeat process until eventually you end up stranded somewhere (I once ended up having to buy a new battery in Arklow just to get me home from a dyno-day run) <_<

When I was remedying this problem on my CB not too long ago I replaced the reg/rect unit and the charging voltage returned to normal. However, this didn't resolve my battery issues, and I ended up having to replace that too.

I don't know if there's any bike specific issues that you should check first, but I do remember a post for a while back where someone had starting/battery/charging issues on their SV. Have a look through the workshop posts and see if you can find it.

edit: I can't find the thread mentioned above, another suggestion is that you put up a new thread in the workshop section entitled SV Starting/Charging Problems or similar... you'll probably get a better response from the SV owners as your query might be a bit hidden in this thread

Pete.

This post has been edited by petecourtney: 01 April 2009 - 11:39 AM

[Lasse]

So how do I determine if my alternator is toast? I can't seem to get any readings when using my multimeter.

[TheBogieMan]

Connect the meter to the battery terminals and run the bike up, get it up to about 2500-3500 rpm and you'll be able to see if it's charging, not charging or over charging by the voltage

[Lasse]

That does not determine if it is the alternator.

That might as well be the regulator or rectifier.

I tried measuring on the field and from the rectifier, but couldn't get a stable reading. Swung between 4 and 12,5v

[TheBogieMan]

sorry...miss read your post lol

To check the alternator you should have 3 wires coming from it into the reg/rec, connect the red lead of the meter to each one of those in turn and the black to earth see if there is any output, make sure you switch the meter to AC current and not DC current though

[Lasse]

Aha! Beginners mistake, I measured with DC

[TheBogieMan]

Lasse, on Apr 1 2009, 03:18 PM, said:

Aha! Beginners mistake, I measured with DC

You could always just lick your fingers, grab one wire with one hand and grab an earth point with the other and get someone wang the throttle open

[proinnsias]

TheBogieMan, on Apr 1 2009, 04:23 PM, said:

You could always just lick your fingers, grab one wire with one hand and grab an earth point with the other and get someone wang the throttle open

bzzzt

An average alternator, with no load (disconnected from the reg/rec) will show 60 - 80 Volts AC from any of the three phases (wires) to ground. They should all be very close to each other in the recorded measurements ...

P

[fabio]

Looks like I'm going to have to replace the R/R on the VFR soon myself...just wondering could I fit one from a Bros or something similar. Are r/r's the same a lot of the time or do they have much differences between them at all?