Podtronics unit.

I am going to purchase a single phase Podronics unit for my Commando roadster 850, so can anyone recommend a decent unit to go for.

Looking at whats available on the market, there is cheap and more expensive choices out there, so i will go with what people have experienced themselves.
Thanks for any help with this.
Neil.

In First place for me is the Shindengen SH775.

Second place is the original zener and rectifier (feel free to replace the rectifier with a modern one)

Third place comes the Tri-Spark MOSFET unit (sold here in the UK by Andover, RGM and Rex’s Speedshop)


A Podtronics (especially the new ones) would be an absolute last resort for me.

This isn’t a Podtronics, but it works for me.https://www.ebay.co.uk/itm/174323895504

gtiller said:

In First place for me is the Shindengen SH775.

Second place is the original zener and rectifier (feel free to replace the rectifier with a modern one)

Third place comes the Tri-Spark MOSFET unit (sold here in the UK by Andover, RGM and Rex’s Speedshop)

A Podtronics (especially the new ones) would be an absolute last resort for me.

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I can understand your preference for the SH775, but why do you prefer the original setup over a Podtronics or the Trispark?
I have been stranded with a faulty zener, original rectifier, Boyer powerbox.. but never with a Podtronics.
( for around 200 000 km on 2 bikes)

@ludwig it's a personal preference and I have probably bored everyone on this forum with my incessant ramblings too many times already!
I do not like short type reg/recs - they deal with excess power by dead shorting the AC feed from the alternator stator and I can't help but feel that is totally the wrong thing to do.


At least the original zener takes the excess power away from everything else on the bike and does a decent job of converting excess power to heat and the nice big heat sink that is the z-plate.
If a zener is kept clean and well connected (electrically) it is a decent and robust piece of kit.


Admittedly robustness is not true for the original rectifiers - the soldered joints on the diodes between the wafer heatsink fins can rattle themselves off, leading to failure (it becomes a halfwave rectifier if one diode joint fails)
But this issue can be addressed with a five dollar fully encapsulated rectifier.



I get annoyed that these low cost regulator/rectifiers are marketed as an enhancement or an upgrade, when I truly feel that they are a major step backwards from what Lucas came up with back in the 60s.
Putting a regulator and rectifier package in the same heatsink, potting it up with a low cost encapsulant that is a poor conductor of heat and dealing with component heat soak by shorting out the input to keep the heat away from the unit in the first place is poor design.

Specifically with Podtronics, I have seen the quality drop off in the last few years since John Healy of Coventry Spares bought the Podtronics operation from Bob Kizer.
John is a well respected guy with a good reputation, so I have no doubts that Podtronics will continue to be the market number one.
However, I feel that people don't understand the shortfalls of the products they are buying, nor the loss in quality since production has been outsourced to Taiwan.


A lot of people say that running an alternator shorted is exactly the same as running it under full load.
I don't believe this to be true.
In normal circumstances, the load is elsewhere - be that a lightbulb or a zener diode, the power produced is being taken away from the alternator stator.

In a shorted condition, the windings in the stator become the load, and they get hotter and hotter all the while the reg/rec is not accepting an input.
I remain 100% convinced that this is the reason why we are seeing a huge number of alternator stator failures (melted and cracked-out resin plus sometimes melted wiring) in the last few years, compared to relatively few in comparison the further back in time you go.


Sorry for being so enthusiastic about this topic, but I hope it gives you some insight into my thought process.

gtiller said:

I do not like short type reg/recs - they deal with excess power by dead shorting the AC feed from the alternator stator and I can't help but feel that is totally the wrong thing to do.

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You are of course entitled to your opinion. But the fact is that the shunt type regulators are by FAR the most common configuration in permanent magnet alternator applications. Not just as an "upgrade" to old systems, but also for new OEM applications. We had a discussion here of series vs shunt R/R devices last year. I saved a quote posted by @Ted Lang in the thread "Biting the bullet on charging system", 3 October 2019. He wrote to Boyer for their opinions on the subject:

I sent an Email to Boyer tech department on this, as to why they favor the shunt type. They tend to reply quickly, which I think speaks very well of the attitude of the company. They replied:

"Thank you for your enquiry, the shunt system is much more reliable, with series regulation on a permanent magnet alternator you can run into problems with very high voltage spikes, the standard 12v alternators produce over 200 volts, with very fast transients, this gives the switching devices a hard time.

Also if the battery disconnects when running the high voltages can destroy any electronics in the electrical system.

The load on the engine when little power is being used is very low, our test alternator motor driven rev's up to full rpm when the output is shorted.
Regards Tech Dept. "

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gtiller said:

Putting a regulator and rectifier package in the same heatsink, potting it up with a low cost encapsulant that is a poor conductor of heat and dealing with component heat soak by shorting out the input to keep the heat away from the unit in the first place is poor design.

Click to expand...

I have spent 46 years of my life designing and manufacturing electronics systems. Thermally conductive epoxy is a staple item in the electronics industry. Thermal management is a key development activity in the design/validation process of introducing any new product to market. NO manufacturer wants to have field failures, and today's engineers aren't stupid. That's not to say that some products aren't designed and built to a price point or that some may be less than optimal in terms of reliability. You get what you pay for.

I've been using a shunt type regulator on my Norton for over 15 years, and haven't melted a stator yet. As they say, YMMV.

Thanks Maylar. I don’t like to repeat my ramblings, but the objections to shunt regulation of these alternators get close to superstition.

I wouldn’t like the cheap Chinese “CBR600”
regulator any more than Gtiller does, if it didn’t work perfectly on my bike, but it does.

@maylar I don't want to get into a pissing contest.
We were asked for opinions by the OP, so I shared mine, based on my experience, what I do with my installs and what I feel comfortable recommending to others.
Then I was asked for my reasoning by ludwig so I shared it.

My recommendations are based on my testing, my research and what I am comfortable with doing on my own bikes.
I wouldn't install a Shindengen SH775 on my bikes, but recommend everyone else installs a Podtronics because they are half the price.


A zener diode is a shunt type regulator too.
Shunt is a term I try to avoid, as they all (including a series-type reg/rec) do that to differing degrees, and shunting is not an accurate way of describing the differences between available types (in my opinion)

Shunting to ground (as a zener does) is perfectly fine provided the power consumed is roughly the same as the power produced.
The regulator shunts the excess to the z-plate, and everything is fine.

And all the while you have a balanced charging system (ie you take out what you put in) there is absolutely nothing wrong with using a 'cheap Chinese “CBR600” ' reg/rec


Where the problems happen is when someone adds a 16 amp high output stator to their bike, and swaps all their lamps to LEDs.
At that point. they are continually dumping about 10 amps.
And with a short-type reg/rec they are constantly dead shorting their alternator stator which does it no good.

But they know no better until something melts, as they are told by their friendly bike shops and their forum friends that they should stick a more powerful alternator on their bike, convert to LED lighting and add a Podtronics, because they are the best.
A failed stator is rarely attributed to the reg/rec in my experience.


I am comparing the actions of a short-type regulator/rectifier to those of a series-type regulator/rectifier.
I am not being negative about the action of shunting.

The Shindengen does not disconnect from the battery - it is constantly connected (it is powered by the battery) - the control circuit disconnects the AC side only.
I have seen no big jumps from my testing, even at varying loads.
The most I have seen from any Lucas-type motorcycle alternator is from an old 3 phase RM20 which peaked at just over 100 volts - that is certainly the exception to the rule (between 50 and 60 volts is far more typical)

I agree with Boyer that the load on the engine is low (a permanent magnet alternator is far more efficient than ones with field coils) but that kind of load is not my issue.
The load problem I have is when the stator coils are dead shorted.


I do feel that MOSFET has better charging characteristics, but until I find a series-type MOSFET reg/rec with a charging voltage that is capped at 13.8 volts, making it suitable for charging a LiFEPO4 battery, I am happy to stay as I am and recommend the same to others.
I assume Boyer don't recommend these either, as their Power Box reg/recs don't use them!


I never once questioned your knowledge as someone that has been in the electronics industry for so long - you clearly know your stuff.
However, thermally conductive epoxy as the correct potting compound versus cheap acrylic resin whose thermal conductivity properties are not nearly as good, plus no thermal paste used between the SCRs and the heatsink to save a few cents is not excusable in my opinion.

Your points are all valid. And I appreciate that you are sharing your opinions and experiences. That's why we're here.

gtiller said:

Where the problems happen is when someone adds a 16 amp high output stator to their bike, and swaps all their lamps to LEDs.
At that point. they are continually dumping about 10 amps.
And with a short-type reg/rec they are constantly dead shorting their alternator stator which does it no good.

Click to expand...

I am "one of those". I have a 210 watt Sparx 3 phase alternator with LED headlamp and a Shindengen MOSFET shunt regulator. If my stator starts to smoke I promise to come back and let you tell me "I told you so"

I thought modern LiFEPO4 batteries needed 14..2 - 14.4 volts, especially the start type versions.

@Madnorton absolute peak charge voltage for a LiFEPO4 cell is 4.2 volts per cell (so 16.8 volts for an automotive battery)
At that point, the cells start to become damaged and life of the battery is degraded.

In my opinion, I would only want to charge at anything approaching an upper rate on a per cell basis, and on the grounds that no regulator/rectifier interfaces with a charge balance port on the battery itself addressing charge rate on a per cell basis (like the manufacturers dedicated chargers do)
For me, personally, I am much more comfortable sticking with the lower charge rate as far as what the reg/rec puts out.

There are some exceptions to this - batteries like the EarthX ones (that you have looked at yourself) that contain a charge circuit built into the battery casing itself that will address the individual cell requirements and make sure that charging is balanced.
These are superb batteries, but you pay for the privilege, and I would suggest these are not the off the shelf batteries people are buying to put in their bikes.

EarthX specify 14.6 volts as the absolute maximum charging voltage, even with their clever BMS circuitry (battery management system)
Shorai is 14.6 volts
Antigravity is 14.7 volts
Ballistic is 14.4 volts
Skyrich is 15 volts
Shido is 15 volts (they have a built in BMS)
Western Power Fire Power Featherweight is 15 volts

Madnorton said:

I thought modern LiFEPO4 batteries needed 14..2 - 14.4 volts, especially the start type versions.

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Although the Li batts, like the Shorai, have a higher voltage per cell at full charge than lead/acid batts, my Shorai has functioned perfectly for years with the output of the OEM Norton charge system, and later, the Alton alternator. Based on voltage/charge ratio, the Shorai is never charged much above 80-85% but that hasn't had any adverse impact on starting or battery life on my Commando. The same Shorai has been in the bike for 7 years.

Madnorton said:

I thought modern LiFEPO4 batteries needed 14..2 - 14.4 volts, especially the start type versions.

Click to expand...

Shorai says 13.1 minimum at idle and 15.2 absolute max. Mine is quite happy between 13.5 and 14.5

I have been following these posts with some interest. I get the series versus short debate. I have an Alton ES fitted to my bike, so big step backward in the power generation department from the Sparx 3-phase set up I was running previously. I have no incandescent bulbs left anywhere on my bike. According to my BSM, the alternator is just keeping up to my load. I am running one of those 'cheap rec/regs' - kind of an experiment more than anything, but I do monitor it's temperature regularly and it is not getting warm at all. I am running an AGM battery, likely a little smaller than recommended, but still starts the bike instantly and never goes flat. I also have a Mk4 Boyer. I put about 500 miles on my bike each week on average.

So, other than enjoying the privilege of not having to carry around a heavy wallet, what is the advantage of installing a high technology modern lithium battery in a 50 year old motorcycle? What am I missing out on? Bragging rights? Keeping up with the Jones's? Honestly, just curious.

Derek Wilson said:

So, other than enjoying the privilege of not having to carry around a heavy wallet, what is the advantage of installing a high technology modern lithium battery in a 50 year old motorcycle? What am I missing out on? Bragging rights? Keeping up with the Jones's? Honestly, just curious.

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Truthfully, you're not missing anything. The allure of the lithium is its small size and weight compared to its cold cranking amps. Its bane is that it requires more from your alternator to be charged and can potentially catch fire if overcharged. I'm using one with my cNw e-start and I constantly monitor it with a voltmeter. If I had to do it over again I'd be using the biggest AGM that I could fit in there.

MexicoMike said:

Although the Li batts, like the Shorai, have a higher voltage per cell at full charge than lead/acid batts, my Shorai has functioned perfectly for years with the output of the OEM Norton charge system, and later, the Alton alternator. Based on voltage/charge ratio, the Shorai is never charged much above 80-85% but that hasn't had any adverse impact on starting or battery life on my Commando. The same Shorai has been in the bike for 7 years.

Click to expand...

I'm chicken to use Li batteries. I've worked on bikes with them and have been amazed at how a little Li battery can spin a MKIII many times without being recharged so I see the appeal. However, in my years, I've seen two Zeners fail open and one PODtronics fail to regulate. Both had lead acid batteries. Lights burning out and batteries going low on water were the problem.

The thought of a fire under my seat with a tank of gas between my legs is why I'm a chicken to use them. A failed Zener will definitely put too many volts across the battery at higher RPMs.

So, you might (probably will) go forever without problem, but if your Zener fails open...

maylar said:

Truthfully, you're not missing anything. The allure of the lithium is its small size and weight compared to its cold cranking amps. Its bane is that it requires more from your alternator to be charged and can potentially catch fire if overcharged. I'm using one with my cNw e-start and I constantly monitor it with a voltmeter. If I had to do it over again I'd be using the biggest AGM that I could fit in there.

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In sizing the battery, like I said, I went on the small size. The battery was intended for a Honda VFR 1200 - 11.2 Ah and 230 CCA. Spins my Combat with ease. The engine was a one-kicker before I put the electric leg on it, and I do not plan on riding when the temps drop below freezing. I do not see the purpose of putting in a larger battery. I get it that if my bike was a MK III, it would need the biggest battery that I could lay my hands on, but the Alton is a different animal in my experience.

Again, am I missing something?

Nope.