GoldenMotor.com Forum
General Category => Magic Pie & Smart Pie Discussions => Topic started by: Denis on December 22, 2009, 07:26:26 AM
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Hi, I received my Magic Pie kit and I tested it with a 36V 9ah battery. I'm not happy at all about performances: 21km/h is the average speed on flat whithout pedalling. PAS don't work correctly: it assist with a lot of retard or don't assist at all. When you install PAS, to use thumb throttle, you must stop pedalling for at least 5 seconds before you could use thumb throttle.
The length of road test was 500 m, my weight 70kg. Did anybody have same performance with a 36V battery (declaration on GM site is 33km/h)? Mybe I did something wrong on connection, what I must verify?
I wrote an e-mail with these questions to GM, but nobody respond me :'( :'( :'( I would like to find a solution, I don't want to quarrel.
Thanks
Denis
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I assume you checked and the 33km/hr on the website corresponds with your wheel diameter? Of course if you take a smaller wheel + same rpm (which is more or less fixed), you will get less speed...
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Thanks for your answer, I forgot, I mounted a 26'' whell, and on site is declared that a 26'' whell with a 36v battery could run at 33km/h
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G'day Denis,
Others can correct me if I'm wrong, but I think the stated speed of 33km/h is the unloaded free spinning speed of the wheel. At 36v I think you should get to maybe 25km/h on a flat with a tail wind.
Muzza.au
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In www.goldenmotor.com, Magic Pie page, is reported, under Magic Pie photo:
eBike Speed: 25kph/24V, 33kph/36V and 45kph/48V (Based on 26" rim, 80kg rider)
In any case I don't reach neither 25km/h :'( :'( :'(
I think I have the same problem as encountred with first release of Magic Pie
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Are your tires pumped up nice and hard and rim true with correctly adjusted brakes?
What is your input voltage by the meter?
Maybe a throttle error and the throttle hall outputting adequate voltage. Test the throttle input and output.
I don't know as there is much I have to learn about the Pie but 21kph is dang slow, so slow old ladies could pedal faster and leave poor Denis in wind.
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Thank you for your answer, but I don't have a voltage meter. I use the battery with another e-bike (250watt motor) and average speed is 25 km/h. I tested the bike with both thumb throttle and twist throttle but nothing changed...
In any case tires are pumped up well and brake don't touch rims.
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You do need to test the voltage.
What type of battery is this?
On a small brushed E-bike 250 watt motor I can get 30 kph and around 27kph~29kph on my GM hub, so every 1.3 volt = approximately 1kph but not with every hub so this is just a ball park figure..
You can get a good voltmeter from the electronics store for very cheap as you only need it for easy to do testing. It good to have all other possibilities out of the way before you can make an accurate assessment to what is wrong.
It does seem slow from what you are telling me here.
Just a little bit more info and more things can be discussed so you can work up to a putting a case together if and when you approach GM for tech support or replacement..
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I'll will test battery voltage as soon as possible. The battery is a lithium (not lifepo4) 36v 9ah and it's new (only 3 months).
Anybody had problems with pas?
When I'll have result I'll post, thank you very much for all your help.
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Please check your batteries. We can only assure you that speed with Goldenmotor batteries. Although it's embarrassing to say that our 36V Battery is actually higher than stated. Like what some people have found out, our 48V is actually 51V. However you can't blame us for doing this because we want to make the numbers look neat and it helps the customers to have a feel about how much power they are getting. We cannot write, 27.4V, 39.2V and 51.9V on the website, it looks weird. :o
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Thanks for your answer, I'll check battery and I think I'll buy your 48 battery. But what can you say about pas? It has a very strange behavior...
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please tell us more about the behaviour so that we can find out.
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This is what it happens: PAS assist with a lot of retard or don't assist at all. When you install PAS, if you want to use thumb throttle, you must stop pedalling for at least 5 seconds before you could use thumb throttle again.
Thanks for your answer.
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hallo denis
user manual copy over PAS function
the magicpei is using same controller as non pie motors [am I right]
power on the pedalec by pressing the cruise control button twice ???
power it of by cutting of the power supply
wat I read about PAS its not working very nice
only full speed and trottle is not working
i am not using PAS at all :-X
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I only mounted PAS and thumb throttle, not yet cruise control button. Really Pas don't work as I would like.
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Question ??? ??? ???: is it possible that bad performances are caused by the missing of brakes with cut off and cruise control? Have someone tested Magic Pie without cruise control and brakes? Thanks for all your answers ;)
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Hello Denis,
I have connected just a twist throttle and on 36V I get around 31 km/h and on 48V I get around 42 km/h, so I think the problem is somewhere else...
Maybe it is just your battery-when I connected the fourth SLA battery wich is quite old, the preformance dropped after 100m-speed went from 42 to 30 km/h, but the battery still indicated 51V...
I really suggest that you try diffrent battery...
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Hi Denis
You say your using a 36v 9A battery that is not lifepo4 please post a link to that battery for me to check out for you as if the continious or maximum ratings are low this could be causing a reduction in performance.
Jim
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Thank you for all yours informations. I toke my battery from my other e-bike:
http://urbanmover.com/products/powerAssistedBikes/UM36SX.php
I don't have other informations about battery, but what I can say is that on the urbanmover bike, battery works well.
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I'm sorry then as without the full specs for the battery I can't give an exact reply.
Jim
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Denis,
You say that the urbanmover is 250w at 36v. That means it will draw a max current of 6.9a from your 9ah battery. Lets say its 9a as the battery is a 9ah battery. On another thread a MP user said they got a max current draw, using 48v admittedly, of 26a. Lets say its 20a for 36v, even that is more than twice what the battery may be able to handle and therefore it may not be up to the task to power the MP to full speed. Drawing more current from the battery than its rated at may cause the voltage to drop and then cause a lower top speed.
Muzza.au
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Thank you all, but what kind of battery I must purchase to reach 33 Km/h. Is it possible to think about a battery lower than 5 kg? ??? ??? ???
A battery with these specification could work?
lithium Ion/ LiFePO4 battery pack is as follows:
1. Battery voltage: 24V, 36V;
2. Battery capacity: 8Ah, 10Ah, 12Ah;
3. Weight: 3Kg~4Kg
4. Dimension: 80x150x250mm (OUT), 64x134x150mm (IN)
5. Cell Chemical: LiFePO4, LiMn2O4, NiCoMn
6. Continuous discharge current: 15A~30A
(From bmsbatterry)
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G'day Denis,
If you want to reach and exceed 33km/h, then go with a 48v battery, but for a 36v battery having read the data sheet for the 36v MP I think it says the max current it draws is just under 25amps (I cant read chinese). Therefore you will need a battery that can supply that amount of current. For example Pingbattery has a 36v 15ah Lifepo4 battery that is rated at 15a but can supply 30a max. It is just over 5kg, see: http://www.pingbattery.com/servlet/the-9/36V-15AH-V2.5-LiFePO4/Detail (http://www.pingbattery.com/servlet/the-9/36V-15AH-V2.5-LiFePO4/Detail)
Whereas the 36v 12ah GM battery (I think it is LiMn204) says it does 35a max, is about 5.5kg and is almost $60 cheaper.
The above is probably the minimum ah rating, of coarse you can go higher and that will also give you greater range, but will also burn a bigger hole in your wallet. :P
You will have to do your research on what you need and what you can afford.
Muzza.au
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muzza.au, thank you! extremly clear, my goal don't exceed 33Km/h (30km/h will be ok too), maybe i'll purchase gm 36v 12ah battery, i'll look around for other and cheaper solutions ;)
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Another question: what is the range with a 48v 10ah using Magic Pie without pedelec? And if you help the motor?
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48v * 10Ah = 480Wh
If you use it at maximum power all the time, 45km/h with no wind or hills: something like 33km of range
If you go at 30km/h all the time, no wind of hills: 60 km
This calculation takes in account the power you need to keep that speed with a bike, considering the wind resistence caused by the speed alone, mechanical resistance from the bike, 5 starts from stop of a 140kg rider+bike and the efficiency of the pie that is considered constant 76,8%.
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Another question: what is the range with a 48v 10ah using Magic Pie without pedelec? And if you help the motor?
Denis, there are many factors that will affect the range, these include:
Speed, overall weight, wind resistance, headwind/tailwind, tyre type, tyre pressures, road surface, hills, gear efficiency, amount of throttle used and amount of pedal assistance contributed etc.
at 48v I can get 40km/h average, on full throttle and I can get about 30km on full throttle
I don't know whether this was with or without pedalling, but the above 30km range was achieved using a 48V 12Ah pack in the Netherlands, which is not exactly famous for hills! So if you live in a hilly area, the range will obviously be greatly reduced.
To offset this, the more you assist the motor, (and the less throttle you use) the further you will go before the battery is fully discharged.
Hope this helps.
Alan
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Here is the spreadsheet I did for this calculation
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ps.: If anyone is curious I can explain the math/engineering behind the calculation :D
It is easy to change the formulas and add the % of the hill so you can know the power you need or even if you bike is able to climb that "steppy" hill you know with your weight.
To validate this spreadsheet I compared to some data from here and ES (data from CA or Wattup for example) and is showed very good approximation with the range and cruise power consuption!
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Thank you for very clear explanation
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I received a new 48v 10ah battery and I immediatly tested with my Magic Pie kit but top speed is only 30km/h :( :( :(
I think 45 km/h, as delcared from GM, is too optimistic! I'm not happy at all!!!
Rider + bike weight ca. 100 Kg 26'' rim
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how did you measure ?
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I've been doing some math homework with the MP test data and you should got maximum speeds close to this chart annexed. The maximum speed are where the curves intersect. This calculation is for 26" rim with 1.5" tire.
(http://goldenmotor.com/SMF/index.php?action=dlattach;topic=1599.0;attach=1644;image)
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ps.: If anyone is curious I can explain the math/engineering behind the calculation :D
It is easy to change the formulas and add the % of the hill so you can know the power you need or even if you bike is able to climb that "steppy" hill you know with your weight.
To validate this spreadsheet I compared to some data from here and ES (data from CA or Wattup for example) and is showed very good approximation with the range and cruise power consuption!
If you could explain the engineering behind the calculations that would be interesting. To me the formula appears to be purely empirical..
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@hardcore: I mesured with a gps on my phone. Is it possible that I received the high torque rather then the high speed?!?
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i don't think so... do you have a speedo?
hook it up to the rear wheel and put in 26inch wheel, in mm.
then it should get 50km/h I think
if not there's something wrong
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Normally I use the gps when I run with my road bike on where I mounted a speedo and there are no diffrences between data registred from speedo and gps, I sure that the speed registered by gps system is correct. I think there is something wrong with my motor.
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News about my tests: I mesured with a bike computer top speed without pedalling and now I can confirm that with my motor I can't exceed 33 km/h. In my case (is it only for me?) is not true what descibed on GM site, 48v <> 45 km/h!!! I'm not happy at all!!!
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denis, I don't know about that weight 100kg? as my bike alone is 30kg. I am 65kg and I am 16 years old.
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With my MP using GM 48v battery I WAS able to reach 44 km/h (I wight 110kg and the bike 28,5kg)
But now I can reach a maximum of 38km/h
I do not know why it was better at the beguinning... I'll do more tests next week.
I doo all this tests at the same place to be sure :D
And my MP really "lost" it's initial juice....
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My weight 72 kg, bike weight 28 Kg, I really suppose that I received the high torque rather than the high speed :'(
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With my MP using GM 48v battery I WAS able to reach 44 km/h (I wight 110kg and the bike 28,5kg)
But now I can reach a maximum of 38km/h
I do not know why it was better at the beguinning... I'll do more tests next week.
I doo all this tests at the same place to be sure :D
And my MP really "lost" it's initial juice....
well, mine got faster but only with about 4 km/h to 5km/h duo the temperature, it's about 0C here in the Netherlands but also my range has dropped
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I wrote to GM to submit my problem, but I did not receive answer!
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I solved my speed issue...
I tested with a GPS and it let me to the stupid conclusion that: I changed my tire from 1.5" to 1.95" and the problem was that I didn't changed the setup of my speed meter... Dumb ::)
Now it is ok lol ;D
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I ordered a 24Volt 16AH Battery with my Magic Pie since here in Australia the law is a maximum of 200 watts. The MP 24Volt combo claims to produce 250 Watts, so I'm only slightly illegal. Yesterday morning, after I putting it all together the night before, I was eager to road test it. Its been extremely wet here lately but in between showers I set off into the hilly suburban streets and then to the long country lane where my grandchildren live on a 30 Acre semi-rural plot.
First reaction was; 'cripes, this has LOTS more power than I imagined, it certainly is NO TOY'. I weigh a little over 100 Kg and it easily coped with all the hills, only the extremely steep ones needed me to help and pedal. The second thing was speed, I'm an old bugger and last year went over the handlebars of a MB which put me on crutches for 20 weeks. My 24 Volt outfit here in the urban locale of a small village on the outskirts of Brisbane, lots of footpaths with the occasional car appearing unexpectedly out of a driveway, who needs to do more than 26 or so Kph?
The other noteworthy observation was the power of the regen brake effect. On the damp roads yesterday I was very much aware the rear wheel could lose traction if the regen 'effect' were used in a sharp corner at speed. Experiencing the vigorous regen effect makes using the actual brakes feel rather dead and lifeless, a bit like stepping on Chairman Mau.
Things that went wrong:
I fitted the Magic Pie conversion to a very old (PINK!) Ladies bike. There is WAY too much cabling and I'm going to have this tidied up by a specialist electric bike shop. I can't do it myself. Also, the deraileur disconnected itself TWICE. I noted this is tapered and I will need to file it flat and maybe get a spring washer to keep it in place. This is the only 'problem' I had and in no way a GM problem. However, I notice the RED light indicating EMPTY on the throttle control shows all the time. It also appears the charger will switch off after 2-3 hours, it gets quite hot. Is this normal?
In summary; I am delighted with this thing, as a kid I lived in hilly Mt Macedon Victoria, I would have given my left testimonial for one of these back in the 1960's. For the approximate cost of registering (let alone insuring) a 6 Cylinder Car in Queensland, I have another vehicle which will be used daily for all the little trips to the bottle shop, my watering hole, the supermarket or hardware shop. It costs SFA to run and maintain, and it gives me the exercise I need and it's fun to ride.
I'm a happy man.
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The other noteworthy observation was the power of the regen brake effect. On the damp roads yesterday I was very much aware the rear wheel could lose traction if the regen 'effect' were used in a sharp corner at speed. Experiencing the vigorous regen effect makes using the actual brakes feel rather dead and lifeless, a bit like stepping on Chairman Mau.
However, I notice the RED light indicating EMPTY on the throttle control shows all the time. It also appears the charger will switch off after 2-3 hours, it gets quite hot. Is this normal?
Bernie,
It's good to hear your bike is working well.
The regen will be more powerful on 24V than it would be on 36 or 48V, but unfortunately there is no adjustment for it.
If they produced these kits with variable regen, it would be much better.
The battery indicator red light should be on all the time, but it should be accompanied by the other two lights when the battery is well charged. As the battery level goes down, the other two light should gradually go out one at a time. (Assuming you have a 24V throttle unit).
I think these battery gauges were originally intended for lead acid batteries, which have a more noticeable voltage drop as they are discharged, unlike the Lithium battery packs, so don't expect the gauge to be very accurate.
As for the charging time, this will obviously depend upon how discharged the battery is. If you've only used 50% of its capacity, it should charge almost twice as quick as a fully discharged pack.
I don't have a GM battery or charger, so I don't know how hot they get, perhaps someone who does will be able to confirm if this is normal or not.
If it's a universal charger (110-240V) it may well run hotter and could even charge quicker with the 240V supply you're using.
Has anyone else used the 24V battery pack?
Alan
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I have the 48v one. The charger does not heat too much, you can touch it with no problem. But for sure it gets hot.
Pay attention: did you changed the voltage switch to 220v?
Does not matter if you use 220v or 110v for the charger, it will charge with the specified current, so, using it at 220v will not charge your battery faster :D
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I ordered a 24Volt 16AH Battery with my Magic Pie since here in Australia the law is a maximum of 200 watts. The MP 24Volt combo claims to produce 250 Watts, so I'm only slightly illegal.
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Actually that might just be perfectly legal as your motor is about 80% efficient, so the power delivered to the street should be about 250W * 0,80 = 200W.
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they can't test if it has more power, can they?
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Thanks guys,
I've never understood electricity. I know there were a number of 19th century European inventor wallers, whose names are to be found on all matters electric: A German chap name OHMS, an Englishman, named WATTS, an Italian named VOLT (A) And I'm pretty sure there's a Frenchman in there somewhere too; AMPERE?.
Therefore I cannot begin to understand why the Regen retardation effect on a 24 Volt would be higher than it would be on a 36V or 48V. The comment I made on the Regen was not intended as a criticism of the MP. I actually think it's an asset, but it does assume a degree of competence on the rider's part. You wouldn't want to be coming down the Brenner Pass in Switzerland at 70 Kph in the ice & snow and dab that brake mid corner.
The 'fuel' lights appear not to be functioning, the RED light is permanently on. Either my old peepers are too feeble to detect light in the green and yellow ones, or they're defunct. I'm not losing sleep because the 24 Volt MP has well and truly exceeded my expectations. It may be the least impressive combo to choose (I felt like a wuss after I placed my order) But it is a real and effective machine.
Also if it is true 250 theoretical Watts become 200 actual Watts at the rear wheel after friction loss, and I am perfectly legal, then I am doing handsprings. If it isn't, it doesn't really matter, 'cause I will tell the local Police woman the former story while keeping perfectly straight face.
My bet is she understands less about electricity than I do.
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they can't test if it has more power, can they?
They could on my old moped a few decades ago, pretty sure they haven't forgotten that trick. ;)
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Also if it is true 250 theoretical Watts become 200 actual Watts at the rear wheel after friction loss, and I am perfectly legal, then I am doing handsprings. If it isn't, it doesn't really matter, 'cause I will tell the local Police woman the former story while keeping perfectly straight face.
My bet is she understands less about electricity than I do.
it's not 250 W in theory, that is what goes into the motor. About 20% is lost but the remaining 80% is delivered on the street, this is what usually counts in legislation. To keep things simple I would just tell them it's a motor that can deliver 200 W, and remember that it's their job to prove otherwise if they want to make a big deal out of it, not yours!
BTW I reckon that the Magic Pie would use 500W at 24 Volt, so you might want to keep a low profile anyway.
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BTW I reckon that the Magic Pie would use 500W at 24 Volt, so you might want to keep a low profile anyway.
That's pretty close, I measured 465Watts on 24V Lead Acid and 525Watts on 25.9V Lithium Polymer.
See this post (http://goldenmotor.com/SMF/index.php?topic=1494.msg9415#msg9415) for more details.
Alan
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My Magic Pie is slow as well with a 48v 20 amp hour ping battery I get 35kph I did some measurements today. Measured at the bullet connectors that go to the motor I had 52.9v when going full throttle on the flat it dropped to 50.2v the voltage across the black and red wire going to the throttle is 4.37v and the voltage between the black and white wire no throttle is 0.82v full throttle is 3.51v. I Weigh 100kg fully clothed. The tyres are semi slicks and are pumped up hard. Has anyone got any idea why the bike maybe slow?
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maybe the 100 kg ;)
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I had the missus follow me in her car and she reckons my 24V MP is doing 29 Klms per hour. I know from my SatNav her speedo is optimistic, so I reckon it does 27Kph on the flat, no wind & my corpulent 105 KGS perched on the seat.
I said earlier that in choosing the 24V I was trying to stay legal in OZ where the limit is a farcical 200W. I never dreamed the least powerful option would be as good as this has proved to be. It isn't often you buy something which exceeds expectation.
For around the cost of registering (let alone INSURING) a 6 Cylinder Car in our State, the MP has turned a very old bicycle into a viable and economical second vehicle which is also fun to ride.