@WEM that article was written by our forum friend
@Jeandr
I was pleased to host it on my site, as I am in 100% agreement with his findings.
Jean used AC transformers to mimic the behaviour of an AC alternator, so I believe it stands up in terms of testing the reg/rec.
However, you should be aware that most of the classic bike world LOVE Podtronics, as they are the biggest brand.
...and most people disagree with our findings and viewpoints on short-type regulator rectifiers often dismissing our comments as complete bunkum.
The Podtronics was designed many years ago with the prime goals of low cost and simplicity in mind.
In fact I recall reading Bob Kizer (the original maker, who is sadly no longer with us) commenting back in the day that he wanted to dumb it down so that any idiot could fit one.
It was designed to replace the Zener and Rectifier on a bike, with everything else left as is.
- So there would be a constant draw of power from the energy consumers on the bike (light bulbs, coil ignition and the occasional toot on the horn)
- There would be a battery and maybe a capacitor on the other end to store the charge
- The alternator stator was a standard output one, matched (by the bike manufacturer) to the rest of the electrical system.
- The primary case was running in a splash of oil to help keep things cool
- It always was a recommendation to ride with your headlight on all the time, as it helps keep the electrical system in balance (also a plus for safety)
If those parameters are adhered to, there is no problem with running a Podtronics reg/rec or one of the subsequent copies that have emerged on to the market ever since.
However, when you start to disturb that balance you'll start to see issues and ultimately failure.
Things that can upset the balance are:
- Installing a more powerful alternator stator - you are not using more power, so when you produce more, the excess needs to go somewhere
- Installing LEDs - you are reducing the power consumption on the bike, so your original alternator is now too high powered
- Running a magneto - you have just taken out the coil ignition, one of the many power consumer, that was keeping your charging system in balance
- Running with no battery - you need one to smooth out the power that is being produced - this is a big help to the sensitive electronics we are installing on our bikes these days
... I could go on - but these days I try to be conscious that people get bored and angry when they read my posts.
The way a short-type reg/rec works (the Podtronics type) is to dead short the AC lines coming from your alternator stator when the target voltage of the battery is reached.
Any small amount of excess overvoltage is then shunted to earth in the form of heat.
So when your battery is charged, and that 'gate' is closed, your alternator is running shorted.
This is a different situation to when you alternator is running under full load - it is designed to do that, and because the load is outside of the alternator windings, the light guage, varnish covered alternator windings will not get damaged.
Basically, the windings in the stator are acting as a fuse in this scenario.
Either, the resin cracks or the insulating coating over the wire inside melts.
@WEM I have a hunch that this is not your problem - if you disconnect the two AC wires that go from your alternator stator to the reg/rec and attach a headlight bulb, I have a feeling you will get a decent output and your light bulb will glow at engine idle, and shine brightly when you blip your throttle.
Fusholders melting is a sign of over current and shorting.
We run a 20 amp blade type fuse on the MK3
... on a pre-MK3 there should be no problem at all downsizing to a 15 amp fuse as
@kommando states.
An SFE fuse is supposed to be fast acting and is supposed to be automotive rated, so it is really weird that it is not blowing - again an alarm bell there.
Look at the breakdown of power consumers.
This is for a MK3, so ignore the electric start stuff, but everything else is the same.
You are drawing well under 15 amps during normal running even with a standard headlight bulb.