Apparent Regulator Failures

[lragan]

In the past month, we have seen, by documentation on this message board (1 case) or by direct observation (2 cases at MOOTMAG 6) three cases of batteries overcharging, boiling out all the acid/water filler, and shutting Maggie down.  Since I ride a 3rd gen subject to the same malady, I resolved to investigate this phenomenon, and solicit your assistance.

What I have learned so far:

1) Our rectifier/regulator must absorb all the energy that the alternator produces which does not go into the electrical system.  More sophisticated systems have feedback from the regulator that excites the field coils in the alternator, so the alternator only produces what is needed.  Our alternators are fixed magnet fields, so this is not possible.  I suspect the system is capable of 18-20 volts when the regulator fails, but don't know for sure.
 
2) From Felicia's experience, it seems likely that there is a temperature problem which may not be catastrophic and irreversible, i.e. when it cools down, it works again.

3) The rectifier/regulator is mounted to the bottom of the battery case, which is plastic, and doesn't conduct heat away from the unit.  This means that it depends almost entirely on air flow for cooling.  It appears to me that most of the air over the unit comes right off the engine, and will be pretty hot to start with, especially if you are climging a long hill.  Be careful in adding accessories, that you don't impede the airflow through this region.

4) It is possible that a battery problem can appear as a regulator problem.  If one of the cells shorts, the liquid in the others will boil out.  So be sure, by replacing the battery, that you actually have a regulator failure before replacing one.  IF you start to boil the second battery, or if the battery voltage goes above 15.5v at 3000 rpm, then worry about the regulator.  Do not run it if the voltage is over 15.5 volts at 3000 rpm, or 16 volts at any engine speed.

What to do about accessories is an open question.  It seems obvious, if you are operating in high temperature, especially climbing hills, to reduce the current through the regulator by turning off accessories you don't really need.  I have a switch on my extra lights out front so I can turn them off in these conditions, (or in slow traffic where I may be drawing down the battery because the alternator will not keep up with the total load); however, if the regulator is failing to control the voltage to the battery in these conditions, so that the battery boils, turning on these accessories will reduce the voltage to the battery (maybe saving it from boiling over) -- and , unfortunately, increase the heat delivered to the regulator module, perhaps further degrading its performance, or even causing catastrophic failure.  Tough call.  I don't have enough information yet to make this one.

I would like to know if anyone else has experienced a regulator failure that "heals itself" -- that is, normal operation is restored once it cools off.

If anyone would donate an old unit to be analyzed, I would like that, too.  Operating or inoperating, both are valuable.  One that still works at normal temperatures would be most informative.

I will update as I learn more.

[Charles S Otwell]

When my regulator went out it did not boil the battery it simply stopped charging. Someone (possibly you) sent me testing instructions to check for bad stator or bad R/R , after determining that it was the regulator I priced a new regulator for $150.00 oem or $100.00 aftermarket. Lucky for me no one had one and I was too impatient to wait to order one. I replaced mine with the regulator from a 450 Rebel, that a friend had laying around his house. I added the second ground to the regulator case as that was the only difference in them. I get a steady 14 volt reading at any rpm . I have since added two 55 watt driving lights with no ill effects and it's been a couple of months with no problems. I think we're going to try the same fix on Guy Wheatley's Magna (the other regulator failure at Mootmag) before he chomps off and spends a 100 plus $$'s on a new one. We are also thinking of relocating it to a cooler place a litte farther from the engine. We'll let you know how it turns out.. If it is for sure the regulator that's bad I'm sure he will have a donor for your project.. Interested in what you come up with ..

[guywheatley]

Charles is right. I'm going to start looking in junk yards for an R/R from any honda and see if we can get it to work. If it works, I'll probably just leave it. I can't see dropping $150 if a free, or cheap one will do.
I'll be glad to send the old one to you for a postmortem.

[lragan]

When my regulator went out it did not boil the battery it simply stopped charging. Someone (possibly you) sent me testing instructions to check for bad stator or bad R/R , after determining that it was the regulator I priced a new regulator for $150.00 oem or $100.00 aftermarket. . If it is for sure the regulator that's bad I'm sure he will have a donor for your project.. Interested in what you come up with ..

So, Charles, do you still have the OEM dead one, or did it go into the trash?  IF you have it, I will pay postage for you to send it to me.

[Charles S Otwell]

I'll look, but I think that it was the first broke part I've ever thrown away ..

[lragan]

You and me both.  At some point, the garage, the attic, the shop, the barn, every nook and cranny gets full and somethin's gotta go!!

[TLRam1]

Glad to see someone trying to tackle this issue.

I don't want to jinx myself........ are there certain years that trouble is popping up on, so far so good on my 94 model, are you keeping track of that? Maybe the ones who have had failures should post their year models & miles or PM you to see if it pertains to a frame of time, maybe Honda used a different mfg at some point.

If it is a overheating issue, could a small "computer type" fan be fastened to the fins?

[Charles S Otwell]

I have noticed several different models of bikes with the regulator located on the outside away from the engine and more exposed to more airflow. I am thinking this might be an alternative to te Magnas regulator location. My magna is a 97 with about 36,000 miles, but my regulator didn't cause a boil over, it just quit charging..

[Sledge Hammer]

It would also help to know the total electrical load typically run on those bikes and what their typical riding conditions were, e.g. stop-and-go traffic, high ambient temperatures, etc. So far as I can tell, all the 3G Magnas used the same regulator assembly by Honda P/N, and if Honda follows the same part numbering practice that some other Japanese companies use, every vendor's part gets a unique Honda internal P/N.

It does seem odd that the design team seemed to go to great lengths to avoid adopting any common sense thermal management practices. How the design engineer could not only provide no significant heat-sinking for such a high-wattage assembly but at the same time locate it in a low-airflow section of the bike and surround its heat-sensitive components with thermal insulation just boggles the mind.

[v4_jeff]

The VFR crowd has been battling this for a while, and they have some good information about it on the VFR World FAQ: http://www.hondavfr.org/faq7_2.html. They've found that replacement reg/rec from Electrex USA (now ElectroSport - http://www.electrosport.com/) is much more reliable than the OEM box. There isn't a direct replacement listed on ElecroSport's site, but I bet something up there would work. For instance, the CMX450 Rebel is listed at $99, and as listed above, that can be made to work.

[trapper]

I have noticed several different models of bikes with the regulator located on the outside away from the engine and more exposed to more airflow. I am thinking this might be an alternative to te Magnas regulator location. My magna is a 97 with about 36,000 miles, but my regulator didn't cause a boil over, it just quit charging..

...and the rectifier on the first gen bikes are located on the side outside of the frame, presumably for maximum cooling effect.  I don't recall hearing of significant rectifier failure issues on the earlier models.    *knocking on poly-laminated wood fiber product desk....*   

[Sledge Hammer]

The VFR crowd has been battling this for a while, and they have some good information about it on the VFR World FAQ: http://www.hondavfr.org/faq7_2.html. They've found that replacement reg/rec from Electrex USA (now ElectroSport - http://www.electrosport.com/) is much more reliable than the OEM box. There isn't a direct replacement listed on ElecroSport's site, but I bet something up there would work. For instance, the CMX450 Rebel is listed at $99, and as listed above, that can be made to work.

That's very good information, Jeff. It also has me thinking that if there were more room under the seat that a custom-designed switch mode dc-to-dc converter would fit the bill, although it would have to have good shielding to keep it from causing problems with the electronic ignition. It would still have to have a rectifier capable of passing the current demanded by the electrical load, but it would keep the regulator from being a load dump for the alternator. The coils and filter capacitors would be the primary drivers for the size requirements. I may have a crack at it to see if it can be done easily and cheaply.

[Smoked U]

Lawrence,

I still have the regulator I took off Baby Vee (96 Magna) in the garage. E-mail your address to me and I will ship it to you for experimentation.

Dave

[lragan]

Thanks, Dave.  I sent you a PM.

[Indonlire]

FYI:

I rode home with the side covers off and seemed to not have any problems.  Got home and after I cooled down I took the seat off and had no boil over from the battery.  I have changed the battery out for a new one. 

I did not change the regulator/rectifier and this morning decided to take it to work and help open.   Started fine and not quite a half mile from home it sputtered and popped and went dead.  I pushed her home and checked the battery - it was charged.  no lights - nothing.  So today I have spent the latter part of the morning and the early afternoon getting that piece of S@%!T battery box out so I could get to the r/r so I can replace it.   Who designed that thing anyway???

Now that that's done I just have to wait for pay day and I'll get the new part.  I'll let you know how things are going.