Regulator Rectifier Gets Very Hot -HELP

[Mark@TO]

Hello from Toronto Ontarion to all my fellow GS Riders. A bit of history. I've owned my 1983 GS550L for 19 years and have 60K on her. We have been through a lot and seen a lot over the years. I have had most of the common electrical problems that GS's go through however at the moment this one has me perplexed.

This spring I pulled my GS out of storage and put a new battery in it. I checked the charging voltage at the battey as I often do and it was 14.50V at 2000RPM and slightly less at 4000RPM. This is always the way is has been, which I find strange, however I have come to accept it as being normal.

One week later I went to go for a ride and the new battery was dead (0V DC.) So I did some digging and found that the regulator rectifier was causing a drain on the system despite the fact it was providing consistant voltage and charging the battery properly. I replaced the battery and the regulator with a factory part (apparently Electrosport has better cheaper ones available!)

Now everything seems to be operating normally with the exception of the regulator rectifier is getting very, very hot. After the bike runs for 5 min. at idle you can not touch the RR with out burning your finger. The leads from the stator are warm to the touch but not hot.

I have run through the fault finding check and everything in that list checks out fine, all tests on the stator, wiring, grounding and regulator rectifier suggest that everything is working as it should. However I am very concerned that the regulator rectifier is so hot. So my question is should the regulator rectifier run so hot that you cannot touch it? If not, what might be causing this? I'm really stumpped on this one.

Any help or suggestions would be greatly apprecieated.
Mark@TO

 

[Charlie G]

The R&R and electrical is not an area which I have a firm enough knowlege which I can write on, but I've read many posts by Posplayer and Matchless which have enlightened me. An example: http://www.thegsresources.com/_forum/showthread.php?t=134690
This thread discusses non-stock replacement R&R's but touches on the heat issue and I believe has references to other threads which will offer you information. Posplayer detailed a heat sink he built for one of his bikes on a different thread somewhere. Quite a bit of info here with a little reading. I wound up using one of the Mosfett R&R's. Good luck.

cg

 

[Nessism]

The factory R/R grounds though the rubber mounted battery holder frame - very poor design. First thing to do is split the R/R ground and run one length to the battery and another leg to the frame. Also, the factory wiring for the charging system is not ideal - much discussed in the archives.

Upgrade of choice is to get an FET R/R ($40 off ebay) and wired it directly into the system bypassing the old and often corroded factory wiring.

 

[Mark@TO]

Hello gentlemen,

I have already replaced the section of harness that links the stator output to the 4 pin plug the RR plugs into.(basically the three yellow wires). This was done years ago when the first RR quit, which in the process melted the connector housing. I have done everything listed in the fault finding chart and by all accounts the charging system with the new RR is working fine. However the RR is getting much hotter than I feel it should. Oddly enough the old regulator rectifier still works and gets just as hot; however it has an internal short that will drain the battery if left connected to the harness for more than a few days.

If I leave the new RR in the bike and run it despite the fact it gets very hot am I at risk of blowing it or the stator up. From reading the forms I have not been able find a conclusive answer to this question. However I have come to realize that the excess load not being used by the bike or charging system is dumped back into the stator. Is there a relationship between this and the regulator getting so hot. I work for an electrical engineering company (though am not an engineer) and one the things we did to eliminate power supplies blowing up on some of our instruments was to create a dummy load to draw off some of the excess current. If I add a running light to the bike perhaps this might use up some of the load the RR & stator are trying to dissipate which might help the RR run cooler. Any suggestions on this.
Again I?m very concerned that the RR is so hot and do not want to damage the stator or new RR unnecessarily.


Mark@TO

 

[posplayr]

If the R/R is getting hot it is either fried or you have some bad connections. Do the tests in the Revised Phase 1 ; it will test how good your connections are. This is extracted from "GS Charging System health" which is in my Signature line.

Finally STEP #3.) Perform Stator Paper Checks. The stator pages checks are not perfect, but they are designed to help you through a process of elimination in determining what is wrong with your charging system. The good news about doing steps #1 and #2 above first, is that when the stator pages say to check your connections you know you already have done it. Here is the update.

Revised PHASE 1 of Stator Pages

ORIGINAL_STATOR_PAGES

 

[posplayr]

I have run through the fault finding check and everything in that list checks out fine, all tests on the stator, wiring, grounding and regulator rectifier suggest that everything is working as it should. However I am very concerned that the regulator rectifier is so hot. So my question is should the regulator rectifier run so hot that you cannot touch it? If not, what might be causing this? I'm really stumpped on this one.

Any help or suggestions would be greatly apprecieated.
Mark@TO

What voltages do you have from Phase 1 Step B and C (measured at 5000 RPM)?

 

[posplayr]

However I have come to realize that the excess load not being used by the bike or charging system is dumped back into the stator. Is there a relationship between this and the regulator getting so hot. I work for an electrical engineering company (though am not an engineer) and one the things we did to eliminate power supplies blowing up on some of our instruments was to create a dummy load to draw off some of the excess current. If I add a running light to the bike perhaps this might use up some of the load the RR & stator are trying to dissipate which might help the RR run cooler. Any suggestions on this.
Again I?m very concerned that the RR is so hot and do not want to damage the stator or new RR unnecessarily.


Mark@TO

Well, the dummy load might work but the issue is if the R/R is in working order, then these connection are not allowing the current to flow from the R/R to the system. Therefore the voltage rises at the output of the R/R forcing it to shunt back to the stator which makes both of them unhappy (i.e. get hot).

The main issue with charging systems is bad connections which has resulted from corrosion (mainly in the crimps). Bullet connectors are the worst because of the low force associated with the female part.

So if you made modifications and checked it years ago, I would recheck. It only takes about 0.02 ohms of resistance to cause 0.2V at 10 amps. That is a very small resistance. Small voltage drops are what you are checking for in Phase 1 B and C. I just recently got mine down to 0.1V total drop on positive and negative side. Prior to that the culprit was the over sized bullet connector going from positive battery post to the fuse box.

 

[Mark@TO]

As I have done the original checks at idle, I will redo them at the higher RPM and post back tomorrow what my finding are. I presume based on what you are saying you believe the regulator should not get that hot and that I must have a connection problem or a fried regulator. I would have to agree that the old regulator is fried as it will drain the battery if left connected. However I hope the new one which was just hooked up briefly (less than 5 min) until I felt it getting hot will be O.k. I would really hate to think that it is blown as well as it cost 280.00 cdn and is less than two days old. Seeing as the stator appears to be fine I will presume that I have a bad connection somewhere which caused prolonged over heating of the old regulator thus it failing. I will re check all of my wiring connections this afternoon.

With regards? to VDC @ RPM as tested at the battery I can tell you this. My GS has always put out more voltage at 1500-2000RPM (14.5 to 14.7 VDC) than at 4000 RPM or higher (13.96 -14.00 VDC) Again I find this very strange as all my other bikes have a very linear charge rate. I.e. the higher the revs the more the charging systems puts out up to 14.5 VDC. I kind of always thought that the Suzuki's were just a bit strange that way. My GS has been in the shop many times for charging issues and no shop has ever commented on the fact that the VDC is higher at lower RPM?s than at higher RPMs.

Thanks for the info I try it out.

 

[posplayr]

As I have done the original checks at idle, I will redo them at the higher RPM and post back tomorrow what my finding are. I presume based on what you are saying you believe the regulator should not get that hot and that I must have a connection problem or a fried regulator. I would have to agree that the old regulator is fried as it will drain the battery if left connected. However I hope the new one which was just hooked up briefly (less than 5 min) until I felt it getting hot will be O.k. I would really hate to think that it is blown as well as it cost 280.00 cdn and is less than two days old. Seeing as the stator appears to be fine I will presume that I have a bad connection somewhere which caused prolonged over heating of the old regulator thus it failing. I will re check all of my wiring connections this afternoon.

With regards’ to VDC @ RPM as tested at the battery I can tell you this. My GS has always put out more voltage at 1500-2000RPM (14.5 to 14.7 VDC) than at 4000 RPM or higher (13.96 -14.00 VDC) Again I find this very strange as all my other bikes have a very linear charge rate. I.e. the higher the revs the more the charging systems puts out up to 14.5 VDC. I kind of always thought that the Suzuki's were just a bit strange that way. My GS has been in the shop many times for charging issues and no shop has ever commented on the fact that the VDC is higher at lower RPM’s than at higher RPMs.

Thanks for the info I try it out.

A couple of comments:

I had a brand new Electrosport R/R that got very hot to the touch (you would not want to hold it) at idle in 1 minute becuase of poor factor crimps in the 4 contact connector from the factory. Basically teh resistance in the connector was fooling the R/R into shunting the power back to the stator.


As far as the reduced voltage at higher RPM's that is a direct result of too much resistance in the positive lead between R/R(+) and battery (+). The more current that is pushed, causes more voltage drop in the connection. So even through the R/R may be regulating at a fixed 14.5V, the voltage drop in the connections between R/R and battery is causes in the voltage at the battery to drop.

Do a search for "foldback" ; It has been discussed before.

http://www.thegsresources.com/_forum/showpost.php?p=978693&postcount=13

 

[GSXXZRX]

The way a rectifier is designed is the reason for the heat. They dump excess voltage to ground, which is a dead short. A short
makes heat as a by-product. This can not be helped. They will get hot.

The rectifier in an car is in the alternator. Engine compartment temps can
reach 200 degrees or more. Do you think that rectifier stays cool.

For the same reason an alternator has cooling slits, a Regulator/rectifier has
cooling fins. 'Cause they get HOT.

A lot of bikes have the R/R mounted on the frame, front down tubes. Why?
'Cause they get hot.

By all means the grounds should have good metal to metal contact to reduce resistance. But in a perfect
system (if there is such a thing) they still get hot.

 

[Mark@TO]

O.k. boys here's what I have done and found out. I did the single point ground tip running ground wires to the harness, frame, and the battery and then re did the test for voltage drop across the negative as described in the updated phase A of the Stator Papers IV. Before additional grounding negative voltage drop was 0.034VDC @5000rpm and after 0.012VDC @5000rpm, so 35% improvement.

Now for the positive side. Long story short about 15 years ago the regulator burned up and melted the connector housing so my local shop cut and spliced a new one in. Not feeling overly happy about this I made a new section of harness to replace the three yellow stator leads that plug into the RR connector. However I did not touch the Red RR output back to the harness. Yesterday I opened up the joint the shop made and found it corroded as well as 30% of the wires strands were frayed & detached. Of course I made a new section of wire from RR connector back to the harness and soldered it in place. So before this repair the voltage drop on the positive was 0.159 VDC @ 5000rpm. After the repair 0.101 VDC @ 5000rpm so a 63% improvement.

Now when I let the bike run the grounds from the RR are noticeably cooler. (Yes!!) The connector housing at the RR is now much cooler as well and so too are the wires that lead from the RR. (Again Yes!!) It's hard to tell for sure but I think the RR might be a bit cooler as well but is still very hot to the touch. However GSXXZRX seems to think that by design this normal.

While I am pleased that the RR connector and leads are much cooler I will continue to remove all the connections of the harness and clean them up with 600 grit sand paper or contact cleaner on all the switches.

Posplayr you mentioned that high resistance between the RR+ and the battery+ is the cause for the voltage drop at the battery at higher RPM?s. However seeing as my voltage drop here is 0.101VDC @ 5000rpm (much lower than the accepted .025) do you think that I still have a resistance issue on my bike. I also measured the resistance between the RR+ and the battery+ and it is 0.5 ohms. Which seems to be o.k.

Thanks for all your help and suggestions guys you really have pointed me in the right direction and I have learned a lot.

I post back once all the connections have been cleaned and inspected.

Mark

 

[Mark@TO]

O.k. Gentlemen here is the end result of my efforts. I have checked the resistance point to point on every wire and found that they were all O.k. (0.2-0.5 ohms). Then I inspected and cleaned, where necessary, every single connection on the entire bike including all the switches. This joyous task basically took me all week working every night for 4-5 hours. I have been able to locate and correct a couple of higher resistance connections in the positive side of the harness and have improved all the grounds as suggested in the stator papers.

I put the new RR back on the bike fired it up and took it for a ride last night. Everything in the charging system seems so far to be working as it should. I measured the temperature of the RR cooling fins with a digital thermometer and it was running at 160-190 degrees F during normal usage. The wires leading out of the RR to the bullet connector were warm to the touch but not hot. The temperature after a trip on the highway is lower as obviously the greater air flow better cools the RR. So I presume that they just run really hot.

Now my next question. I have always been under the opinion that a little valve tick at idle that goes away when you put the motor under load is acceptable. I have been told over the years to adjust the valve lash on the higher side of the tolerance rather than the lower end as the valves usually tighten up over time from pounding into the head. Mechanics have told me that it's better to hear a little valve tick than hear none at all as this might mean a valve could be staying open. Do you guys share this opinion?

Is a little valve tick O.K.

Thanks for all the advice and help with the RR issues.

Mark@TO

 

[posplayr]

O.k. Gentlemen here is the end result of my efforts. I have checked the resistance point to point on every wire and found that they were all O.k. (0.2-0.5 ohms).

If you run 10 amps through 0.2 ohms that is a 2V drop. That is way too much for the Battery to R/R connections.

I measured the temperature of the RR cooling fins with a digital thermometer and it was running at 160-190 degrees F during normal usage. The wires leading out of the RR to the bullet connector were warm to the touch but not hot. The temperature after a trip on the highway is lower as obviously the greater air flow better cools the RR. So I presume that they just run really hot.

You can presume that YOUR R/R runs hot but I suspect it is because you have poor connections to the R/R. You measure the voltages as described in the stator pages you will likely find out you have large voltage drops. And if you do this will explain your poor charging and why the R/R is getting so hot.

You should already know that TOP of extended industrial temp range for electronics is +85 Deg C. How much do you think that is in DegF? If you are at that level at the cooling fins, rest assured that the junction temps are well above that.

 

[Mark@TO]

Well I'm very perplexed because I have done the voltage drop test between the battery positive and the RR output lead as outlined in the updated stator papers. At 5000rpm the DC voltage is 0.135VDC which is lower than the 0.250VDC listed as acceptable in the stator papers. Is 0.135VDC not acceptable? Have I missed the point or done something wrong?

I think that what you are saying is that 0.2 ohms resistance in the cable that runs from the RR to the fuse box is too high and will produce a significant voltage drop which will cause heat. What value would be preferable 0.0 ohms, is that possible? How can I attain this? If 0.2 ohms is too high but the DC voltage drop on that wire is 0.135 and I?ve checked every connection on the harness what more can I do?

Thanks again for the input.

Mark

 

[posplayr]

EDIT; Sorry I did not see the earlier post about doing the single point grounding; so it does look liek you have very good connections now between the R/R and battery . Coudl you pleasse just sumamrize how well the charging is now .

here is what I found; both of which are good and show you have good connections.

Before additional grounding negative voltage drop was 0.034VDC @5000rpm and after 0.012VDC @5000rpm, so 35% improvement.

At 5000rpm the DC voltage is 0.135VDC which is lower than the 0.250VDC listed as acceptable in the stator papers.

Now what is the voltage across the battery at 5000 RPM? It needs to be over 14.0V.

Well I'm very perplexed because I have done the voltage drop test between the battery positive and the RR output lead as outlined in the updated stator papers. At 5000rpm the DC voltage is 0.135VDC which is lower than the 0.250VDC listed as acceptable in the stator papers. Is 0.135VDC not acceptable? Have I missed the point or done something wrong?

Sorry, when someone comes on and says everything checked out, it is not clear what they checked (I now see your results were spread out across a few posts). Without mentioning some specific measurements, I'm left to assume the required measurements were not completed.


The 0.135V is very good .

I think that what you are saying is that 0.2 ohms resistance in the cable that runs from the RR to the fuse box is too high and will produce a significant voltage drop which will cause heat. What value would be preferable 0.0 ohms, is that possible? How can I attain this? If 0.2 ohms is too high but the DC voltage drop on that wire is 0.135 and I’ve checked every connection on the harness what more can I do?

Thanks again for the input.

Mark

to get 0.135V with 10 amps flowing you are talking about only 0.014 ohms of resistance. Unless you have a very good ohm meter, you will not be able to measure that. That is the primary reason for measuring the voltage drops.

 

[posplayr]

If your connections are good, that doesn't mean that the R/R is charging correctly, just that it is connected properly. Actually unless the R/R is outputing 10 amps, the voltage drop tests are not even conclusive.

 

[Mark@TO]

First off let me say thank you very much for your patience. I really do appreciate all the help you are offering me I would be lost without it.

Now the saga continues. Last night I drove my GS home and parked it in the garage. It seemed to be running great except for the high heat at the RR. I let the bike run at idle for about 5 min while I re checked a couple of measurements. All of a sudden it began to run very erratically as if it was miss firing. I quickly measured the voltage across the battery and found it to be 12.78VDC at idle. I shut of the bike and measured the resistance from the stator leads to the casing ground and found it to be 3.87 Mega ohms on all three leads. I then performed the stator no load test and found that the voltage between one of the 3 pairs was 30VAC. I shut off the bike tried to touch the stator casing and it was smoking hot. I touched the clutch casing and it was noticeably cooler.

Thinking that I might have blown my new Suzuki RR I swapped it out with an old one I had from a parts bike. That particular RR over charges and so I knew that it should put out at least 15VDC. I started the bike and measure the voltage at the battery and it was 12.80 or so at idle. When I revved up the bike to 4000RPM the voltage at the battery rose to no higher than 13.00 VDC for both RR?s. So I did the only thing I could. I turned off the bike went in the house and poured myself a nice double shot of Crown Royal and proceed to drown my sorrows.

This morning I decided to try and start the bike just to see what would happen and to my surprise it fired right up, ran very well and was charging the battery normally (Thank god I didn?t kill my new RR!!). I measured the voltage drop across the positive and found it had gone up a bit from my last reading. Now it was at 0.190VDC at 5000RPM. Which is still within your spec of less than 0.250VDC. I also checked the v drop across the negative and it was still very good at 0.015VDC.

So now I?m of the opinion that at cold to low temperatures the stator is sort of working and once it heats up to operating temps it begins to short to ground. However I?m no expert and am wondering what you think?? I have been told that that anything over 50 Mega ohms is pretty much an open circuit (OL). However 3.4 Mohms is boarding on connectivity. It may not be a complete dead short but I would think that some energy is passing to ground.

The only conclusion I can arrive at is that the stator on my bike is in need of replacement and may be the reason why the RR is getting so hot and perhaps why it was running erratically last night. So now the question is are the Electrosport Stators and RR?s really better than the factory Suzuki parts? If I replace both the RR & Stator with Electrosport parts can I use the new Suzuki RR as a spare if someday I need it? So basically can you mix and match Electrosport parts with Suzuki parts?

I checked Electrosports web site and they have the RR for my bike however the stator is temporarily out of stock. I will call them on Monday and see when they will have them back in stock.

Once again Posplayr thanks for all your help!!

Once I get my new stator and RR installed I?ll post back to let you know what all the new Voltage drops and charging measurements are.

Mark.

 

[Mark@TO]

Well I just went to Electrosports web site and this is what comes up.

"Dear customer, ElectroSport is changing ownership. We have stopped the online ordering for maintenance and updates until Wed May 27 and will start shipping orders as of that date. We thank you for your patience!

The company will continue to cover warranty on all sold items.

Our technical staff will continue to provide technical support for our products during the time our warehouse is closed."

Oh man just when I need them the most!! I guess I might have to wait a while to order my new RR & stator

 

[posplayr]

It sounds like you have a good handle on the issues. You may already realize that your voltage drops are going up when charging properly because there is more current flowing.

 

[T mac]

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