PD: Primary Drive Make your own Generator

JustPlainBill0

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i can't help thinking that you could fork out the cash for an Alton and be riding the bike within a day, instead of trying to re-invent the wheel. I run two bikes with the latest type and they are absolutely fine, and yes the bikes do get ridden. 2-3 times a week and also at night to the pub!
Maybe when you're 82 you too will find the chase as much, or more rewarding than the catch. Projects like this keep me learning, involved and not riding a rocking chair. (I also have a couple of other bikes to ride - and do, though not to a pub.)
 

Mark Fisher

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Maybe when you're 82 you too will find the chase as much, or more rewarding than the catch. Projects like this keep me learning, involved and not riding a rocking chair. (I also have a couple of other bikes to ride - and do, though not to a pub.)
you could be right, assuming I even make it to 82! good to hear that you're still riding though.
 

oexing

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Glen,
big question to your problem with the LiFePo4 battery is, what was the root of the defect and what was the consequence ? I´d rather believe the Podtronic went over the Jordan and only then the battery was cooked with overvoltage.
Anyway, I will get some motorbike rectifier from Aliexpress, for three phase brushless generators - three yellow wires/three phase motor - output into two wires positive and negative 12 V - more like 14 V in fact, I guess, for charging a battery. You can get them for 15.- to 25.- €€ and I expect them to handle all overvoltage coming from the 24 V or even 48 V AC brushless motors. A test will show, no big deal if the electronics send smoke signals. I could go for a 48 to 12 V converter anyway, but a motorbike rectifier would do both jobs, the converting of AC output from the brushless motor to DC plus limiting voltage to 14 V for battery charging. The Podtronic is way overprized at € 80.- something .
The typical modern motorbike alternator is mainly a three phase AC alternator, a large sort of flywheel with magnets in its rim, rotating around a set of coils . The current from three sets of coils is fed into - well, the motorbike rectifier. The small China brushless motors are basically the same principle, only the positions are changed: The magnetic rotor spins in the centre and the sets of coils surround the rotor.
And yes, I could have the Alton any day , for an acceptable sum. But then, I like to be creative and think about things someone else may not yet have come upon possibly. So especially in a forum more brains might come to even better ideas to benefit our community ?

Vic
Motorbike rectifiers Aliexpress
Rectifier 14.5 V 35 A
 

Monkeypants

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Oexing wrote "I´d rather believe the Podtronic went over the Jordan and only then the battery was cooked with overvoltage."

I have three of these Podtronics regs mounted, so I would rather believe it was the battery that did everything in.
I bought 2 of these Ballistic batteries. They were expensive but the claim was that they would last ten years. Both were dead in 18 months.
A Google search for " Ballistic Battery problems" yields hours of reading. Maybe that's why the company shut down last year.

A search for Podtronics problems doesn't provide much reading at all.
From what I have seen of the Podtronics units, they are very dependable.
I believe Alton now supply Podtronics regulators with their Alternator kits.
Years ago they supplied another Chinese built reg that looked just like the Podtronics, but had different internals and was not so reliable.
Paul Hamon( Alton) wrote an article about this, I'll see if I can find it.

Glen
 

Monkeypants

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Here is the Paul Hamon info. It's from an email discussion Paul and I had regarding shunt type regulators ( Podtronics)vs switching type ( Shendingen SH775)

Paul wrote

"Back to the experience of Alton : I mean the regulators we supply with the PM generators done to replace the 3 inch dynamos. It is important to know that some shunt type regulators are so BAD they destroy the coils of PM generators in a short time. After various experiences from multiple sources, we finally chose PODTRONIC to supply with our generators. They are shunt type, the most economical way (theoretically), but they are top quality.
We were very happy with test results. We supply them since end of 2012. This is now more than 6 years of very favorable feed backs with a very low number of issues."

Glen
 

timetraveller

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I'm out of my depth here, but then, when did that ever stop me having an opinion? My understanding is that 'shunt type regulators' are Zener diode systems, similar to those produced to go with the early Lucas alternators fitted to UK bikes in the 60s. I looked at the pictures of the regulators and all of them seem to have heat sinks which makes me suspicious. If so then these work by turning surplus charge into heat. You are thus taking all the possible power that the alternator can generate and turning some of it to heat, It is entirely possible that there is some electronic wizardry involved these days but if not then this is about as primitive a method of regulating a voltage as is possible. More sophisticated regulators work by modifying the current to the field coils and thus the alternator never generates more power than the bike needs. This latter system takes less power from the engine and drive system but is more expensive to make.
Is there someone out there who is competent in these matters who can give us a definitive explanation of what is going on here?
 

oexing

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Norman,
I am pretty sure the modern regulators don´t apply Zener diodes which produce a short to earth above their fixed voltage maximum. These do transform excess voltage and current into heat.
The typical dc dynamo or even three phase car generators need some of the power to produce a magnetic field wherein windings rotate. Rotating windings in a magnetic field produce voltage and current. So in a case when the field is generated by electric power you can modulate the power that goes into the field and so you can limit the voltage that is generated by the dynamo or alternator. This type of generator needs copper windings for the field plus windings where the power output comes from.
Now looking at permanent magnet alternators, you get the field from the magnets which you cannot regulate. So the higher the speeds of the magnet rotors the higher the voltage goes. In long passed times the excessive voltage was sunk to earth by the Zener and went up in heat.
The modern type of regulator for these permanent magnet generators will most likely apply the pulse width modulation PWM electronics. An AC alternator, single or three phase, no matter, outputs a sine wave form AC voltage. Depending on the speed of the rotor, the voltage may reach 20, 30, 40 V , not suitable for your 12 V battery. So the PWM just cuts each sine wave at the point of 14 V along the curve. It does not sink the rest of the voltage into earth, just cuts it. There is certainly some power loss into heat as from any semiconductor apparatus, but no way all of the excess current gets lost in heat. When you look at the regulator that I ordered last night, it can output 35 amps at 14 V . So that would be almost 500 W , you could use that for cooking if all of the power was turned to heat. But in reality the component is only 90x85x28 mm large, so one can guess what amount of power will be lost in operation. Anyway, 500 W is only 3/4 of one hp and we´d be happy to have maybe 150 to 200 W - just one quarter of 1 hp.
Yes, this kind of regulation seems to be undersophisticated but then you get an alternator which has no brushes, no collectors, no flying windings. It is even suitable for in- oil operation like in bevel Ducatis. Once the motor spins the alternator produces power without a battery. But then I guess a battery will be easier on the regulator for cushioning voltage spikes possibly, I don´t know. Those China regulators should be allright with 30 or 40 V at times - anyway, cheap enough to have some on stock.

Vic
Rectifier 14.5 V 35 A

Honda three phase alterator
Honda alternator brushless
 

JustPlainBill0

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Non-VOC Member
My China spindle motor arrived yesterday, so I loaded it up in the drill press and got some voltage readings, then did trial fitting on the Rapide. Along the way, I shot some quick and dirty video and posted the result on YouTube:

I've had time to reflect on the experience and in general think that Oexing (Vic) is closer to a respectable home made generator than I am. My (intuitive) sense is the spindle motor just isn't robust enough to handle the load from the driven sprocket over a long period of use. The added bearing Vic intends to mount on a brushless motor will be of great value for keeping the generator alive. (If the bearing were mounted outboard of the sprocket, on a steel plate between the primary cover T5/3 and dynamo cover ET63 , it would be ideal.)
Furthermore, the low voltage produced by the spindle motor at 2800 rpm with a 55 watt load makes me wonder if it will keep up with demand at normal road speeds. I've ordered a power analyzer https://tinyurl.com/14-Watt-Meter (I didn't even know they existed) to learn how many volts, amps and watts the spindle motor does output. Again, Vic's choice of a motor making it's power at lower RPM seems more practical.

That said, I will probably continue with the spindle motor experiment until Vic succeeds in his efforts and I can buy one from him, or I buy an Alton. :D

I think the mount and collet will be useful for cobbling something together when you don't have years of experience as a machinist. I will not do anything irreversable to my engine block, so the alternative is to try to adapt the mount to fit with longer studs for the dynamo clamp ET176. What I found today is that the Miller dynamo and spindle motor shafts are on nearly the exact same level (height) when in their respective mounts, facing nose to nose.

DSCN8344A.jpg


That should make fitment easier. It also shows that an outboard mounted bearing is also feasible for the spindle motor.
 

Bill Thomas

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In the 70 s, I did a quick Bodge, Cut a Dynamo body in half, Fitted 2 drive ends and put a V pulley on the end.
This Jack Shaft has a V belt to run an Alternator from an old British Mini car, Built in regulator, More Power than I will ever need !, Does not over charge a 4 amp cheap battery, 12 v.
IT'S STILL ON THERE :) .
For my new Bike, I have a Walkernator, Ready to fit, Very well made, Much neater than my effort, Better belt type. Cheers Bill.
 

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timetraveller

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A comment on any bearings used as 'outriggers' to take some of the strain on built in bearing in motors. With the Walkernators I use heavy duty 20mm I.D. bearing at each end of the dynamo replacement and have found that there is so much 'hammer' at the drive end due to the Vincent design that the drive side bearing can wear well before the other one. This has happened on bikes with 30,000 to 50,000 miles of use. The solution is that all the later models use a tube between the two bearing inners which is clamped tightly between the two inners. This ensures that both bearing inners rotate together. Thanks are due to father and son Appleton for this solution to the problem.
 
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