quick guide for Newbie?

[AlDk]

I am a newbie in the E-bike world who has just bought a recumbant trike (20kg) with a winther fairing (10-15kg). I live in Europe in a hilly area. I know that the law in my country states that you can use a maximum of 250W (I can see yours actually functions as a 350W isnt that right?) and that the engine has to shut of when you go more than 25 kph (I cant see if yours does that). Now, I am not so worried about getting caught even if I break the law because it is difficult to see that you are breaking it...

What is the advantage/disadvantage of the Magic Pie compared to the old types?

What is the advantage/disadvantage of more Watts?

What is the advantage/disadvantage of more Volts?

Which solution would you recommend for me?

[Leslie]

What is the advantage/disadvantage of the Magic Pie compared to the old types.

The Pie.

Advantage.

It has a larger diameter stator so more torque is easily achieved by the Pie.

A more modern design, with integrated controller, saves space.

Disadvantage

The internal controller is harder to repair.

If you want to get away with being easy to ride a faster bike, the MP can attract attention.


Older hubs.

Advantage.  

Cheap good solid hub. more inconspicuous.  Needs an external controller so this is easy to replace.  Good torque at high speed.

Disadvantage.  

The smaller gearless drive makes it A little shy on take off torque.

What is the advantage/disadvantage of more Watts?

Advantage.

More power and or faster speed.

Disadvantage.

Harder on both motor and batteries.  Bike needs to be stronger and stricter safety concepts are wise to observe. Distance may be impeded.

What is the advantage/disadvantage of more Volts?

Advantages.

From the consumer point of view, being able to make volts higher or lower gives the user the ability to get more speed or less speed.  It gives the user a some variables to play with, with their motor.

Creates more magnetic intensity and can give more speed and torque.


Disadvantages.

From an engineers point of view not much is achieved by using high volts.  You need longer coils adds more resistance, the battery has more cells and has more resistance.  Some of the fastest electric motor for cars are only 48v.

Higher volts can be more dangerous.

Can introduce unacceptable inefficiencies to your system..

You need a powerful motor for the recumbent the pie should do you well.  Any hub will work though.  I rock about on a little HBS36 at 60v carting 34kg of lead on my frame for years., it a little weird but some work on the acceleration and balance has fixed a lot of the weirdness.

Shedding 27kg of lead on my bike should give me back some torque.  I guess if I can do what I do on the small HBS36 im sure anything to or above this hub will suit your needs.

[GM Brazil]

Really nice answer 317537, this information will be very useful!!
Very well explained! 
Thank you! 

[Leslie]

Cheers.

A good nights sleep helps.

I only answered the questions.

Advantages of more current and disadvantages.


Advantages:  More AMPS/current.

More available torque, can chose a lower volt high current motor, either use gears or dimensions of hub to convert to RPM, use of less cells in series and larger or more in parallel, both equate to less internal resistance. More current can put to use use paralleled motor coils to increase size of motor and decreases the resistance.

Disadvantages.

Requires expensive or many parallel cells to provide the current and may have problems affording to replace large cells or finding and repairing bad parallel cells.  Usually requires more infrastructure to operate.  EG Larger, fets, cables connectors, switches.  
Voltage, AMPS, Watts, and resistance has a simple law that makes energy and power draw measurable.

Voltages X AMPS = Watts

Watts / AMPS = Volts

Watts / Volts = Amps.


If you have a lamp that uses 12v at 5 amps.

12x5= 60 watts.

If you have 60 watt lamp using 5 amps the voltage supply required is 12v.

If you have 60 watt 12v lamp it will draw 5 amps at 12v.


More current effects any existing resistance in your system by this formula.  Amps X resistance = voltage drop across R.  V drop x the current = loss watts.

As with more voltage.

Voltage / resistance = current.




Resistance isn't futile in all of these equations and consider your battery chemistry and series connections and connectors all take there toll on both current and voltage and taking our watts away.


Say the entire resistance of a bike systems adds up to .01 ohms.

Amps X resistance= volts.

Say you draw 20A X R.01= .2v output, and equates to a voltage drop across R.  .2V at 20 amps equates to 4 watts wasted with no gains.

All you need to do is double that .01 ohms and its 8 watts.


More about series cells.


A large single cell can have a resistance as low as .003 ohms.

If you had a 60v pack 22 cells would work up an internal resistance of .066 ohms, at 20 amps, You're losing 26 watts before the power comes from the pack.

But 60v @ 20 amps equates to 1200 watts.  26 watts seems small.  But add the motor the fets and connections.  And that figure of .066 gains more effect on the entire system.

Voltage / resistance= current.

If your system requires 50v @ 20 amps, any resistance above 2.5 ohms and voltage below 50v @ 2.5 ohm is going to restrict your current.  



50v /2.7 ohms= 18.5 amps
47v / 2.5 ohms=17.4 amps.

55v / 2.5 R= 22amps.


And this is why you can draw more current from higher volts.

As you can see a higher volt works better on the higher resistance system and so it should as the windings required need to be longer.

I could go on all day about this.

[AlDk]

Thanks, it helps but even though I've had physics in high school your answer still twists my brain, and I wouldn't know how to explain it to a child, so if you could make it EVEN simpler?

other questions. It is more expensive for me to by direct from china because of customs and VAT than from a seller in Europe. The problem is that the seller in England sells different kits than Golden motor, eg

36v 250W with a BAFANG motor and 10 amps LiFePo4 (i think) and I think the controller is a different one to

or
golden motor 500 or 1000 W with 3 SLA batteries 36V and a controller of 25 amps

now: how good is a bafang motor compared to a 250W golden Motor?
same with the different batteries - what are the differences?

they can be seen at http://www.alienbikes.co.uk/page14.htm and other pages

so I cannot buy a pie from europe, and the combined kits are different - what to choose?

thanks!!!

[Leslie]

You should ask your UK dealer these questions.  

The Pie is better than all those.

I think that http://www.goldenmotor.co.uk is going to put up some kits for sale.  They already may have a Pie waiting to send out.


     Alien Ocean
AlienOcean European Hub
1-9 Plantation Street
Lochgelly KY5 9LP
UNITED KINDOM
Website: http://www.goldenmotor.co.uk
Email: sales@goldenmotor.co.uk       

I would advise getting your kits from the dealers not the manufacturer. Not that GM in china is evil or something but there be GM dealers for a reason.

Ive never owned a bafang before so my opinion doesn't matter.

Try avoid SLA's even though the 250watt hubs work OK with them, the larger direct drives really need lithium or else you need a ton of lead to avoid peak and max cont, drive and regen currents destroying them.

Try the email and ask if they can get you a Pie.

sales@goldenmotor.co.uk    

[Leslie]

http://www.alienbikes.co.uk/page15.htm

Hey here is the HBS48v 1000 watt hub.

I would advise getting something bigger than a 12ah SLA or a 10ah lithium, but that just me.

[Bikemad]

The problem is that the seller in England sells different kits than Golden motor

Try contacting the other UK dealer:

Da Vinci Mobility
6-8 Carraway Road
Gillmoss industrial estate, Liverpool
L11 0EE
UNITED KINDOM
Tel: +44 1515481999
Fax: +44 1515480333
Email: sales@davincimobility.co.uk

I contacted them at the end of last year, just to see what they stocked and this was their reply:

I have a container on the way with a good seletion of kits. Eventually we will stock most products.
If you have something in mind you require let me know we will get any parts you require.

So they should hopefully be able to help.

Alan
 

[AlDk]

Okay, I'm seriously considering buying the Pie and have a seller on standby.

I've seen a screen shot of the Pie program (http://goldenmotor.com/e-Bike-DIY/PI-200%20GUI.jpg), but I am not sure I completely understand all of the features.

Does anybody know whether I can program it so that it helps max 25 kph and/or 250 w still having a 36V/12A liMn battery? (so that I could also program it to go faster?) Could I tell it to use 24V although the battery is 36V? Can I turn off cruise control and have it help with percentage support when I pedal and with the throttle control if it helps with 50%, 100%, 200% etc? And what does the regen percent signify? And REV?

should I buy a battery with more amps?

I know this is probably very basic knowledge, but it sooo helps to get very basic answers :-)