GM controllers - max watt / amp limits - another downside?

[Webby]

(Caveat - I'm not moaning here as the MP is really unbelieveable fun, ridiculiously efficient and will not now do without it  so in the interests of goodness and curiousity I wondered what other thought about this ..)

I'm approaching 1500 miles on my one front pie with internal controller so feel qualified to judge. I am well aware of past posts about the GM controllers (Int / Ext) power limits; its true and that has been verified with readings from my journeys for max amps (~30) and peak watts (~750) ...

... but I was not expecting this behaviour that I believe is happening. Its only really apparent when going up hill and that is that if I exert greater power from my legs to the pedals I actually don't/can't really go any quicker (0.5 mph max) up the hill than if I exert just a moderate amount of power! VERY STRANGE!

Now that got me thinking that perhaps the limit on the controller is such that even if you want 'add' the power and go faster on the other free wheel that the controller wont let it through (so to speak). Now I do go 16mph up the very steepest hill I have and usually 20mph on moderate hills - so like I say I am not moaning.

If this is the case its a pity but also where is my wasted energy going? I suppose its lost to heat in muscle and pedals, chain and whatever else. Or am I just imagining it?

If my theory is true then I think that Golden Motor should at least beef up their standard issue controllers a little more.

[Andrew]

Evening,,, sounds like you've been on the pop - lol

I think the term 'cogging' is used to explain this phenomenon?? it's to do with the resistance of the magnets within the motor.
Someone else maybe able to give a better explanation.  

Actually, I think I've been on the pop

Try this....

The cogging effect is the attraction between the magnets and the stator poles when at rest; this attraction and cogging is easily felt when trying to turn an electric motor by hand. A common misconception is that cogging is caused by the copper coils; however, this is not the case. An unequal attraction between the magnets and the stator results in the rotors reluctance to turn. The magnets sit comfortably at rest over a pole, and when the rotor is turned, they must move over an air gap before reaching the next pole. The rotor resists the turning, the magnets attempting to stay bonded to the current poles, until just over halfway through the air gap, where the attraction to the next pole is stronger than that of the previous pole, resulting in a "clunking" or jumping effect at low RPM (such as when trying to turn by hand). This is the cogging effect, resulting in a large torque required to begin rotation.

[DirtyGinge]

I think what happens here is that we are spoilt....

Back in the early days, when I believed that I was going to pedal more than the motor, I found my knees knackering very quickly.......I think that its the fact that we forget how much energy input is required to keep speeds upwards of 18MPH;.....so we pie, then try to increase / take over and suddenly it it just too much force on our legs.....

Saying that though, I don't know if its my imagination, but the cogging seems a little less on another controller....

[Andrew]

it is true that we are spoilt. I could not believe how slow my push bike was and how much effort it took to pick up a decent speed on my new bike before I put the mini motors on.

[suprted1]

0282 BAC controller, 23 Amps straight out of the box, running at up to 60V.

[Dummy Dave]

where is my wasted energy going? I suppose its lost to heat in muscle and pedals, chain and whatever else. Or am I just imagining it?

I have better range when I help the motor.  Is your 'lost' energy just staying in the battery until needed?

[o00scorpion00o]

The pie is a bitch to pedal power or no power even on level ground, This motor is really suitable for anyone who wishes NOT to pedal along!

I got my new motor, capable of taking around 2kw, it's a geared motor that freewheels and I took it out today for a spin, I've no battery yet and I peddled 6 miles and my god, the difference is amazing. You do notice it there, but it's nothing to the Pie motor. I am very happy now!

If you want a bike and like to pedal, then the Pie is not the motor for you, If you got ultra steep hills then it's for you or you pull trailers!


Mark

[DirtyGinge]

Hi Mark

Im looking at MAC/BMC motors at the moment, which route did you go ?

[o00scorpion00o]

Hi Mark

Im looking at MAC/BMC motors at the moment, which route did you go ?

Mac from cell-man E-Mail him he is on the ES forum, he could take a few weeks to reply.

He has upgraded the gears which should take 2kw! It's a nice motor, small light enough and freewheels, ah glorious freewheeling! 

Best of all it's far cheaper than a BMC which I don't think has better gears any more, certainly I think the MAC gears now might be stronger!

I haven't tested it out as I'm still waiting on my 8ah Zippy's from Hobby King!


Mark

[DirtyGinge]

nah, plug it into the mains....what could possibly go wrong lol

[Webby]

Andrew - Looking at all the responses ... I think your right about being spoilt with the MP (for sure), I have to say that I have not rode a 'normal' bike since I got my pie and thats testimont to the pie me thinks. However if I did, I expect to be really surprised at what I've got used to 

Dummy Dave - Also I agree that when ever you pedal you are saving the battery and actually I like this fact.

...but in this scenario I do not want to save the battery, I want push that pie over the 'limit .. but it seems I can't do that in any substantial way.

At the moment I conclude not to bother to 'max' it out pedalling up hills as the return is negliable

2kw geared motor?? now you have lost me here!! 

[DirtyGinge]

Hi kev..on mobile so forgi e the typo...

Question is..what do you require.:....
If its excercise, throttle and cruise less..if its more speed, then an infineon will give you 120
Speed boost.....trouble is, an athlete wil put out about 400 watt max, cyclingat twenty plus requiresmore wattage than our poorl little legs can supply....
I average about twelve to sixeenwhenpeddling.......22is never going to happen, so whenyou take over from the pie, do it at less than twenty...if you canmanage more, you should be in a team fuor twenty. Twelve.........
Hope this makes sense...my kneez gave me this kind lecture...........

[o00scorpion00o]

2kw geared motor?? now you have lost me here!! 

basically the internally geared motor improves efficiency, the gears allows the motor to spin faster as motors work more efficiently at faster rpm's!

It also improves torque.

geared motors are also a lot smaller and lighter than direct drive motors such as the Magic Pie!

They also freewheel allowing you to pedal much easier without motor drag, which will allow you to pedal further without using the battery so you will get longer distances!

The downside, if used much above their rated power the gears can fail but they are improving, and the mac 500 from cell-man over at endless-sphere has upgraded gears tha tshould handle 2kw of power, which in a geared motor is very powerful!

1 other downside is no regen, though I recommend hydraulic brakes for any E-Bike, regens only useful function is slowing down the bike, you don't put much energy back into the battery!


Mark