Review of the Newest MP4

[Morgen 3Eman]

Sorry I annoyed you.  Didn't mean to.  Thought we were having a discussion.   You from OZ?

TTFN,
Dennis

[Supchrgamx]

didnt annoyed me.    we are having a discussion.   Canada
trying to make lite conversation and failing badly
didn't think of induced voltage , just a little rusty , I guess
need to draw a picture to get a handle on this
and if I remember right if you short the winding it becomes a brake

Laurence

[GM Canada]

Hi Laurance,

I want to apologize in advance for being a terrible person.  I am not questioning you to hurt your feelings, but to learn.  An Aussie called me a bully a while back, and wanted me kicked off the board, and I am still stigmatized by that. 

So…….

hi Dennis,

I have seen you post this more than once. I do recal when this happened, but what was actually said I do not. It hardly matters though. I can say I have had simular situations. I hammer out a lot of email some days and I guess they don't sound friendly at times. I usually give people quick answers or links to the questions that are asked the most like this 4 answer reponce to four questions

1- yes
2- no
3- read this http://www.goldenmotor.ca/FAQ/questions.php?questionid=126
4- have no experience with that try the forum www.goldenmotor.com/SMF

Enjoy the ride
Gary

Most people just accept the answers, some ask more questions and the occasional comment about being so breif.

I realize your posts are nothing like this but I have found inserting a few smileys in makes a differnce in the response. Like...

1- yes
2- No
3- read this http://www.goldenmotor.ca/FAQ/questions.php?questionid=126 
4- have no experience with that try the forum www.goldenmotor.com/SMF 

Enjoy the ride
Gary

I know bad smileys and your posts are nothing like how I answer email. But still tossing in a smiley every now and then never hurts. Just think about your wife and the difference in how you feel when she looks at you with a smile as opposed to a cold stare.

Just my two cents, don't mean to offend. Just making an observation. 

Gary

[Morgen 3Eman]

Hi Gary,

I have to tell you that I do not understand how putting a smiley face on it will change the fact that a changing magnetic field will induce a current in a conductor, but if you think it will help, I'll try it.

Thanks for the suggestion.

TTFN,
Dennis

[Bikemad]

The MP4 vector controller can have the overvoltage protection set using the USB lead and it can be programmed for up to 65V maximum, but the default setting is 62V for the 48V battery.
The two large capacitors are marked 80V, one of the smaller ones is rated 63V and two others are rated 25V. But as I cannot access the tracks on the PCB, I don't know whether the smaller capacitors are subjected to full battery voltage or not.

I'm guessing it may be feasible to set the maximum to 65V and then use a 15S LiPo pack fully charged to 63V without experiencing any problems, but I haven't tried it yet.

Here's an update:
I have just tried running my latest MP4 controller on 15 x 5Ah LiPo cells and I can now confirm that it works.
 
I set the controller's overvoltage protection to 63V (15 cells @ 4.2V) and the 15s battery voltage was reading 62.53V.
Maximum current reading was 30.28 Amps, Maximum Wattage was 1565.9, but as the LiPo packs I used are very old and weak there was a huge voltage drop of ~15 Volts at full power (which is almost 25%!) 

As my new LiPo pack only drops ~5% with a 45 Amp load, I would expect a good 15 cell LiPo to drop to around 58V, which should produce 1756 watts of power at the same 30.28 Amps. If the shunt on the vector controllers could be modified to allow ~50 Amps (like I did with my current MPII controller) the torque would increase by 65% and the maximum power should also increase to around 2900 Watts!!

Fortunately for me, the BAC-601 also seems to have survived the higher voltage, and here is the maximum unloaded wheel speed achieved by applying full throttle with the wheel raised off the ground:



I didn't have enough time to carry out a decent long test, but at least I have confirmed the MP4 controller can be used with a battery voltage in excess of 60V, whereas the MPIII controller cannot.    

Alan

P.S. I'm not sure if I have used enough smilies to keep Gary happy, so here are a few more just in case!
                                                                           

[Morgen 3Eman]

Thanks for the laugh, Alan:)

It brought a smile to my face and page:)

The 80 Volt cap is most likely for bulk filtering the supply voltage, so it should survive on 63V, but I would be very scared as the voltage supply went much more than 65V-70V.   I have no idea what the 63 V and 25 volt rated caps are for.  Inductive phase angle correction? Probably not.   Perhaps they have a linear power supply for some internal function?    Good engineering practice says they are being subject to around 45V and 18V.  Perhaps there are some opamp circuits running plus and minus 15VDC?  That would be a typical usage for the 25V caps.  Just a guess, again, but zero crossing detectors would be pretty handy to have for triggering functions.
 
Ya gotta love Gary, eh?  He must be fun in a pub for a bevvie.

Have a nice day
Dennis

[Kauaikit]

Thanks Alan...good to know a 15s5p pack will work! And I will report my results on this end with both MP4's @ 63v.

So, do I work GM, again, to get their R&D department to up the amps to 50 on the MP4 controller....for controlled testing of course?!?

Philip @ GM has already to told me, "the MP4 is fast enough" when I requested my last special order HS MP4!   

I'm fine with the torque on the standard MP4, and the top speed of the HS MP4...now, I just want both for this "poor mans BionX model D and Tidalforce X version ebikes".

Kit
S.CA USA

[Bikemad]

I'm fine with the torque on the standard MP4, and the top speed of the HS MP4...now, I just want both for this "poor mans BionX model D and Tidalforce X version ebikes".

Perhaps you should build a dual Pie bike with a high speed MP4 on the front and a standard MP4 on the rear, this would give you the best of both.
More torque and more speed than you have at the moment, and the slower motor would only begin to hold you back when you try to exceed 37 mph!

Alan
 

[Kauaikit]

Alan....that was my first initial plan with the newest MP4, but was told by GM that many people were falling @ higher speeds with a dually setup. Maybe it was just with the MPIII?

So, I was concerned about cogging on the front hub @ higher speed, but your suggestion sounds like something worth testing. 

BTW, have you done a level speed test @ 63v, and what level speed (lbs) are you getting on your standard MP4?

Kit

[Bikemad]

Hi Kit,

I haven't tested it flat out on the road as the legal limit over here is only 15 mph and the maximum permitted power is a mere 200 Watts!!

My bike that has the MP4 fitted is a little bit conspicuous and it tends to stand out like a sore thumb rather than blend in with other cyclists:



So I would definitely be asking for trouble riding it fast on public roads.

With my usual 8 cell LiPo pack I don't go fast enough to draw attention to the motor's power, so I am hopefully not going to get stopped by the police, and as the majority of my riding is done off-road, I am not overly concerned.

Alan
 

[Kauaikit]

Alan....what a shame, when non bike riders actually make laws that must be obeyed by actual bike riders. The Euro and Canadian ebike laws are just silly! Even the spandex riders can go 30+mph/48kph on leg power alone.

Bike riders, in the USA, are generally still under the radar. I've never been stopped or questioned in the last 4 years that I've focused on only riding electric street bikes. I retired from years of hard core mountain biking after knee surgery. So, the street riding still gives me my cardio workouts. And it's also fun to compete and test different ebikes and their setups on my regular 12mi/19.2km course. And of course I'm always on the lookout to race these spandex riders.

I've not yet setup an electric offroad mountain bike.

My regular gym drive to vehicles is either a '06 Harley Road Glide or one of two '68 Ford Cobra Jet Mustang GT 428ci fastbacks. I like American muscle, hence my initial ebike interest in the Wavecrest Tidalforce bikes for street riding.

Kit

[Supchrgamx]

what do you know about Canadian law kit

dennis, we still talking?
I knew you had dry humour, made me laugh

Laurence

[Morgen 3Eman]

Hi Laurence

It is surprisingly hard to  make me shut up:)  What ya got?

Have a nice day
Dennis

[Supchrgamx]

some where on the web

And then there is the issue of eddy-current losses. Eddy currents are too complex to fully explain here, just know that for very high RPMs, you need thinner laminations and a lower pole-count, or…you will reach a certain RPM (different for each motor design) where there is a sudden and seemingly unexplainable increase of heat.

One example of this is the popular MAC geared hub motor from em3ev.com. The standard model performs well at 36V and 48V. But when builders began using it at 60V and 72V (which makes it spin faster), some of them would encounter heat spikes when they were at their highest RPMs (caused by eddy currents and a high switching frequency). Paul at em3ev.com now provides the option of an upgraded MAC with thinner laminations and a factory-installed heat sensor for builders who want to run higher RPMs.
A stator core must be made from some type of steel, but they are not solid blocks. The stator is made from many thin slices (called laminations) that are stacked together to make the final shape. Laminations that are 0.50mm thick are common and very affordable (due to the high volume of production). The thinner (and slightly more expensive) 0.35mm thick lams are the next common upgrade. The High-efficiency Joby motor (no longer made) is capable of 10,000-RPM’s, and it uses 0.20mm thick lams.

High-RPM laminations also have a higher content of silicon in their steel. I don’t know why that helps them run cooler…but it does.

Laurence