Much More Powerful Pie Now!!!

[Leslie]

I will add the pie runs a little slower than other hubs for the same amps, this is not because it is not as good, this is because it has more coil slots and a longer winding with larger stator diameter.

The Pie begs for more volts IMO.

Like if you run a 12v 50watt halogen bulb it will pull 4.1 amps at 12v

50w/12v=4.1 amps

12v/4.1= 2.9 ohms.

If we run the 2.9 ohm load at 13 v

13v/2.9 ohms = 4.5 amps.

One more volt  to the bulb  equates to 400ma more current. 13v*4.5 amps= 58.5watts and so we get 8.5 more watts from the bulb too.

The same applies to a motor that has a little bit of resistance taking down the current to the motor.

There is a point where saturation will not allow any more current through the coil.

[o00scorpion00o]

That's some setup Leslie. That poor bike does carry some heavy loads! That's why I think a pie would suit your needs better? I think going faster than 25mph with those loads would be dangerous.

I am happy with the pie's performance, I would like to be able to hit 30 mph or a little faster, but I think I would need a lot more voltage. So that's not possible now.

I would really love to compare the pie with the BMC V3 with the same battery and controller. I know the guys over at the sphere were testing it with BMC's 50 amp controller and it melted phase wires, ( obviously ) And had to rewire 10g to the axle. It's supposed to be really fast @48-52 v up to 40mph? And the torque is supposed to be incredible. It's a pity there is no way to increase efficiency like that without using gears.

GM say they will have an option when ordering pie II, to change the winding for speed or torque, But I would imagine if I was looking for 30+ mph that I would suffer a major loss of torque? 

Good luck Leslie with the rewinding, I can only imagine it will be slow and painful ! 

[Leslie]

That's some setup Leslie. That poor bike does carry some heavy loads! That's why I think a pie would suit your needs better? I think going faster than 25mph with those loads would be dangerous.

I am happy with the pie's performance, I would like to be able to hit 30 mph or a little faster, but I think I would need a lot more voltage. So that's not possible now.

I would really love to compare the pie with the BMC V3 with the same battery and controller. I know the guys over at the sphere were testing it with BMC's 50 amp controller and it melted phase wires, ( obviously ) And had to rewire 10g to the axle. It's supposed to be really fast @48-52 v up to 40mph? And the torque is supposed to be incredible. It's a pity there is no way to increase efficiency like that without using gears.

GM say they will have an option when ordering pie II, to change the winding for speed or torque, But I would imagine if I was looking for 30+ mph that I would suffer a major loss of torque?  

Good luck Leslie with the rewinding, I can only imagine it will be slow and painful !  

Yeah the gears are little bit of a downer on the BMC motors.  I think what use is all that torque if it is going to hit the nylon gears on the rugged terrain.

The 20" cast rim pie is sort of what I got my eye on for the heavy loads.  The issues with the size will not be so bad, as you can imagine not having the problems with spokes and rims may be a relief.  The roads are pretty harsh on my rides.

Yeah it;s arguable where efficiency lies the best geared or not geared.  If your in hilly terrain and good roads the geared motor is prolly a good choice.

I have some hills as I live in the higher areas but when I get down it is all flat sugar cane farms for miles.  This is where the gearless rules.  The gearless torque at higher speeds is awesome.

If you don't mind doing some pedals the gearless is great.  Not even performance cars at the lights could beat me off the mark with my big SLAS sinking some pedals into the take offs with my old GM controller and hub.

The slapperty slap down named the the MP dual the monster and king on the hills.  This was a 36v setup with 2 MPv1 with a 26" wheel.   The 9C won the single hill climb and beat the BMCV2 S 600 W.  The BMC may not be the best for torque but seems to be good at putting it into speed.  It did win the speed test.  As I said the Magpie is just asking for some volts.  36v magpie isn't what I would enter into a running race against anything.



http://www.slappityslapdown.com/Slappity_Slapdown/2010_RESULTS.html

I would like to see a 20" pie doing this hill test.

Yes the slappity slap down. LOL you should check the vids out, it's funny as, and I do hope to see it again in 2011 with more entries.  Like Clyte and the BMCv3. And the few other hubs.  Even a cyclone setup would be cool to see.

I would like to see some Clyte X5s doing their stuff.

http://endless-sphere.com/forums/viewtopic.php?f=3&t=17311

Interesting thread here an MP at 110v going at 80kph with great torque for a gearless pulling 40 amps. motor 100 deg C 4400 watts.  I would give it just a little more amps at 110v and see what happens.  Every 1 amp at 110v equals 110wats.  So another 5 amps is going to give 550 watts maybe too much.

IMO the Pie wants some more volts.  

[o00scorpion00o]

I saw the slappity slapdown vids, those guys are crazy!  The dual pie they said is a monster climber, so thay had a total power of 1500 watts. And I'm pulling just over 1800 watts on a single pie. I got over 60 amps (3kw) before I fried the internal controller. Insane torque@ 60 amps!  Still, it is a monster climber alright @35amps     I would like to see them test the BMC V3

From what I have seen on the sphere, I think the pie is most efficient @48-52 volts? and at higher voltage would be less efficient? I love the fact that the current drops to around 18-20 amps on the level once up to speed, So I guess the pie is quiet efficient. Anyway Ill keep riding as it is and enjoy it. The other thing now is to try and improve cooling to the fet's.

[Leslie]

Ahh! at last my brain is fried.  To much information and learning. 

Night all.

[o00scorpion00o]

Sniff Sniff I think my fun pie days are drawing ever closer to an end! After my ride in the woods I came home and was cleaning the bike when I noticed 5 loose spokes. They did not break, The end bits seemed to have come off and are inside the rim, I can hear them as the wheel turns. Has anyone god any idea if I can fix this, or prevent it happening again? It's one thing after another in this ebiking world! I really don't want to have to take this wheel apart again, oh the pain!  

Here is a pic, I'm sorry about the quality as I had to take it with my phone. My Girlfriend has taken the camera home to Germany for a few days!

[Bikemad]

Mark, unfortunately you will have to remove the tyre, inner tube and the rubber rim tape to access (and refit) the lost nipples.

You should be able to do this without removing the wheel, but it will be a bit of a fiddle removing and fitting the tyre and tube assembly with the wheel still in the frame.
With the tyre, tube and rim tape removed, you should be able to persuade the nipples to fall out of the access holes in the rim.
Then you need to get them threaded onto the spokes again. I had to use a pair of fine pointed tweezers to get mine started, but as you have the modified spoke pattern on your wheel there might be an easier way:

If you have a spare spoke, you should be able to screw it into the wrong end of the nipple a couple of turns.
Wrap some sticky tape around the end of the spoke to prevent the nipple from threading on any further, and you should now be able to poke the nipple into the rim and line it up with the spoke and carefully wind it on as far as it will go.
Now, hold the small end of the nipple (the spoke key end) with one hand, and you should be able to simply unscrew the spoke you have just used as a tool to fit the nipple in place.
Now repeat this procedure for the other nipples and then gradually tighten them until they are approximately as tight as all the rest, whilst checking that the rim still runs true. With your wheel, you may be able to do this with a flat bladed screwdriver, failing that use a spoke key as normal.

As five nipples have already come loose, there's a very good chance that all the other spokes are going to be too loose and will probably need to be tightened up a bit more.

Start with the spoke next to the valve hole and work your way around all of the spokes in turn and try to tighten each of them by 90 degrees (assuming they will turn that far without getting too stiff).
When you reach the valve hole, re-check the tension of the spokes by either plucking or flicking them.  If they don't sound tight enough, go round again until all the spokes are correctly tightened ensuring  the rim remains perfectly true. If the spokes are tight enough, the nipples should not come loose, but if you want to put a small blob of locking compound on each spoke/nipple joint it probably won't hurt.

The spokes on my rear wheel (which I rebuilt over five months ago) have not been touched since the wheel was refitted, and they are still nice and tight and the wheel is still perfectly true (without any locking compound being used).

Hope this helps.

Alan
 


 

[o00scorpion00o]

Hi Alan,

Thanks, that was really useful information as I have not got a clue about spokes! 

They all seemed tight to begin with as I checked them often enough, So I'm wondering if I'm going to continue to have problems with them or is it because of the extra torque I have been getting out of the motor? Some of the hills in the woods are really steep and maybe I should avoid it from now on, it really is fun. But the poor motor has to haul my 220lb ass up there! 

This is strange as there has been noise from the spokes all along. It's hard to describe, like maybe they are stretching or something like that!

[Leslie]

superglue
 

Never thought of that one, I thought of silver solder.  But that is a little permanent, I could offer a better product for the job.

Maybe some JB weld instead?   

[Leslie]

 220lb ass up there! 

 

I had many early spoke problems with the weight thing.  I had them pull out of rims, snap, spokes pull out of nipples, and wobbly wheels, coming loose, I had two wheels for two bikes and soon I had one with a full set of spokes and another missing as I used them for spares.

It took me ages to learn the right balance of tension, rim strength

In a word you lucky they are still good.

[o00scorpion00o]

I had no trouble what so ever with my old motor. and Pat who is heaver than me has no problems with spokes either! I wonder would the lack of rear suspension have anything to do with it? Some of the roads I ride on are atrocious, and all those knocks and bumps must not be good!

Ok way past bed time zzzzzzzzzzzzzz

[Leslie]

I had no trouble what so ever with my old motor. and Pat who is heaver than me has no problems with spokes either! I wonder would the lack of rear suspension have anything to do with it? Some of the roads I ride on are atrocious, and all those knocks and bumps must not be good!

Ok way past bed time zzzzzzzzzzzzzz

Yes I use a hardtail MBT.  I think this would make a large difference.  It was good to establish some pretty heavy standards to my technique of riming.

I am planning to go full suspension with my next build.  I should be well prepared for any problems.

[o00scorpion00o]

okay, Spokes fixed. Rather easy I thought! Lucky I did not have to take the wheel off. The torque arms are holding up really well. I will keep a closer eye on these spokes in future. Funny thing is, I did keep a check on them, they did seem tight all along, but I'm now thinking that maybe they seem tight, but the nipples could still be loose? Anyway another lesson learned in Ebiking school today! 

Leslie, I had a full suspension bike, the rear suspension was good for ass comfort, but the thing was all over the road. It was not suitable for electric at all. I could not afford the price of a really strong suspension bike. The front suspension on the new one however is terrific, and my hands and arms are not bouncing all over the place! I will buy a suspension saddle post in the future. Actually I'm just thinking that more and more bikes I'm seeing are beginning to be less strong for conversion to electric, especially the rear drop outs, and the way they are made makes it tough to mount torque arms!

[o00scorpion00o]

Check this baby out!!! 

http://www.sunsetmtb.co.uk/shop/index.php?product_id=1188&category_id=12


Now that would make a superb electric bike!!! No chance of a full rack on the back. I wouldn't trust a seat post rack with a 20 amp ping!
So many really good bikes out there, but there is so many problems with rak mounting, weak drop outs etc. The price is really crazy, I know you get what you pay for, but for 4000 sterling you could buy a half decent car!

[Bikemad]

okay, Spokes fixed. Rather easy I thought! Lucky I did not have to take the wheel off.

Well done Mark, I'm glad you managed to do it the easy way without having to disturb all those nice new wires.

Anyway another lesson learned in Ebiking school today!

I bet you never thought Sunday school would be so useful.

Did the other spokes tighten up much?

If the suspension seat post doesn't help, fatter tyres should make a difference. I'm running on a pair of 26 x 2.35 tyres with no suspension whatsoever and they certainly do improve the ride.

Alan