36V ecrazyman running slower than 24v (well, not anymore!)

[fitek]

I replaced the 24v SLAs on my bike with 36v of Makitas. My top speed has dropped from 21mph to 18.5mph. The bike will accelerate very slowly after 17mph and then "bump" up against the top speed with a frequency of 1 or 2 Hz. I'm pretty sure I got the hall sensors right, but you never know with those evil things (could damage to the hall board make it run like crap? I've resoldered the wires many many times). Voltage, even with sag, is good, always > 34v. Only difference is batteries and I lowered LVC to 19v or something like that (using Fechter's post). Uphill torque is pretty crappy too-- I ran the 36v batts on another bike with the same controller (but different gearing, slightly lower) and it was absolutely flying around 15mph.

What gives?

 

[John in CR]

I replaced the 24v SLAs on my bike with 36v of Makitas. My top speed has dropped from 21mph to 18.5mph. The bike will accelerate very slowly after 17mph and then "bump" up against the top speed with a frequency of 1 or 2 Hz. I'm pretty sure I got the hall sensors right, but you never know with those evil things (could damage to the hall board make it run like crap? I've resoldered the wires many many times). Voltage, even with sag, is good, always > 34v. Only difference is batteries and I lowered LVC to 19v or something like that (using Fechter's post). Uphill torque is pretty crappy too-- I ran the 36v batts on another bike with the same controller (but different gearing, slightly lower) and it was absolutely flying around 15mph.

What gives?

Sounds like a wiring problem unless you're not getting enough current out of your new batts. How many amp hours do you have at 36V vs your 24V of lead?

John

 

[fitek]

12ah vs 3 year old 40ah SLAs. Which were probably around 10ah in real capacity.

 

[fitek]

Well one of the hall phases totally just up and died today. I'm going to swap Kollmorgens and see what happens.

I hate hall wires.

 

[fechter]

Yes, a bad hall signal will make it run like crap.

I'm ready for sensorless controllers! You might try contacting Keywin and see if he has any more of the sensorless adapter boards for his controllers.

 

[africanandy187]

I still don't understand why hall sensors are needed, why does the controller need to know where the phase is?is it for efficiency or what? why dont 3 phase industrial motors have hall sensors?

 

[fitek]

You need the hall sensors because it makes the logic for commutation easier. To make a 3 phase motor spin, you have to apply voltage to one or two of the phases in a particular order depending on the position of the motor. You can store this ordering easily in an array in a microcontroller's memory; the hall sensors will tell you where in the array you are. Without the hall sensors you don't know where the motor is when it's stationary. You have to just guess and see what happens to the back emf or use a pedal first controller. It's a little tricker to write the code for this and it makes the performance of the motor when it's starting up kind of crappy. I could care less, the hall sensors are such a pain in the butt reliability wise...

 

[fitek]

Yes, a bad hall signal will make it run like crap.

I'm ready for sensorless controllers! You might try contacting Keywin and see if he has any more of the sensorless adapter boards for his controllers.

Ok, I think will.

 

[fitek]

I wonder if this problem is related to what everyone was experiencing with the Puma and original ecrazyman controller. Since I'm using a 20" wheel it has to spin a bit faster (compared to a 26") to get up to a normal speed like 20mph. Jonathan loaned me a crystalyte controller for a while in the summer but I only used it with the Makitas once; I swear I thought it was much faster.

I'll try upgrading the xtal and increasing the current limit while I'm at it Anyone know what a safe current limit is with the stock FETs-- I seem to recall 40 or 50 amps rather than 28. I could order new FETs from Digikey too but I feel the need for speed *now* hehe.

The newer ecrazyman controllers don't suffer from this, right? Are those different than the Infineon controllers? I haven't been able to keep track of the developments.

 

[fitek]

What are the MOSFETs in this thing anyway? They are labeled as T430 BN7S9L. The latter finds nothing on Google. Digikey carries 3 MOSFETs named AOT430, they're 75V 80A n-channels in TO-220. 11mOhm and 114nC and 268W max. This controller has 12 FETs so I guess double the power per channel or 1608 Watts.

Off to pick up a faster xtal now (20mhz)

 

[fitek]

Success! With a 20mhz xtal I can now hit 23mph on the flat. 21mph comes fast then the last 2mph take some time.

Upped the current limit too but I don't know how much. My meter maxes out at 30a.

 

[fitek]

Current limit doesn't seem to be working right. I swapped the shunt in the meter and redid it to read 3 amps per tick. I've gobbed half the two shunts in the controller with solder and the current is about 25a full throttle, just like before. Bike is equipped with 12ah of Makita batteries; I also tried reducing to 6ah to make sure it isn't something with the packs, but nothing changes.

Hmm.

 

[methods]

I am seeing the same thing with a 6 fet Ecrazyman 36V controller
Bike will not go over 22mph no matter what I do.
Simulations show that I should be hitting 35mph no load

I swapped all the fets to 4110's
Bumped the current limit to 60A for a test, same thing
Hits the limit at 22mph

I reprogrammed it with all different settings for speed, reverse speed, LVC, etc.
I think I am hitting the electrical RPM limit of the board.
My particular motor has 23 poles.....

So what is this about a xtal swap ?!?
So you looked up the chip, found its max frequency, then swapped up?

What if the programmers did software timing based on know cycle time?
There must be some kind of dividers they used for Timer A, Timer B, etc.
Seems like it would skew the timing between phases...
sounds like a sketchy move (ballsy though, I like it)

So you say it works fine eh?

hmmm.....

I will give it a go!
Anybody who rides a bike that bad-ass must have a few tricks up his sleeve :wink:

-methods

 

[fitek]

So what is this about a xtal swap ?!?
So you looked up the chip, found its max frequency, then swapped up?

So you say it works fine eh?

I will give it a go!
Anybody who rides a bike that bad-ass must have a few tricks up his sleeve :wink:

-methods

Well, PWM motor control works by varying duty cuty. 50% on time at X hertz doesn't really make much difference between 50% at Y hertz if X and Y are similar. And the jump from 16mhz to 20mhz or 24mhz is big but not an order of magnitude or anything. I can see where you might be worried about shoot through or something, but if I were writing the code for the controller I would make sure to leave a lot of room since who knows what crappy FETs the guy doing the assembly is going to stick in there.

This wasn't my idea, I remember reading a post from Knuckles that it works.

Bad-ass bike? I hope you don't mean the one in my user pic. That's a girl's princess bike!

The bike I actually use is a tandem and no one pedals right now. So I have to pull 300+lbs of weight at speeds that still satisfy me. And if my larger friends are onboard it could be 400+lbs. I need more power!

 

[methods]

I am talking about the yellow /white / black one with the regenerative pedals, office chair seat, and Drill battery packs.
I sent that picture around the office. Everyone was quite impressed

They were not surprised when I credited a software engineer from the Bay Area.

I got my trouble sorted out. I modified myself right out of a modification.
Getting 2,400W out of the little 6 fet guy now.

-methods

Edit: Do you have more pictures of the yellow bike btw? Would much appreciate it. I love bikes like that. Couple weeks ago I rigged my office chair up to my wife's chopper bike. Was all fun and games till the controller blew and I had to peddle a chopper with no brakes all the way home in a motorcycle jacket....

 

[fitek]

2400W!

How'd you get that much going?

I gobbed solder all over the shunt, but it didn't do any good.

I either need more power or multiple gears. The latter won't be easy with this setup.

 

[methods]

Great pics!
Love that thing.

I swapped the fets out for 4110's (which btw are down to $2 each)
I soldered the shunt down to 1.2mOhms
I inspected all the traces and added solder where appropriate
I wired up the programming port and ran it out
Also added an on/off switch

I then rigged up a RS232-TTL converter and ran the modification software (for newer infineon boards $50!)
http://cgi.ebay.com/48V-350W-brushless-controller-for-E-bike-scooter_W0QQitemZ260323431675QQcmdZViewItemQQptZScooters?_trksid=p3286.m20.l1116

Changed the current limit to 50A (actually set it to 15 but you get 50 since I soldered the shunt)
Changed the LVC
Calibrated the new current shunt.
Fooled with some other stuff too.

This is the teeny tiny surface mount credit card size controller

It pulls a hard 50A all the way to 28mph then rolls down to the freewheel current
After blowing 5Ah the other night ripping up and down my street the box was hardly even warm.

Amazing.

-methods