I want to go 20mph, but i'm stuck

[Ethan102]

Hey guys, i was afraid of making a post like this because i thought many people have asked this but i can not for the life of me find any information to help me. I want to go 20 mph (since that is the limit an i want it to be legal) on my ebike but something is limting me. I can easily go to exactly 15mph and then i stop getting power and just stay at a constant speed. i kinda like it since i can go 50 miles on a 10ah battery but i want to go faster. Dont we all? I have a 36v 500w kit that i got from Ebay (http://ebay.com/itm/New-36V-500W-Electric-Bicycle-E-Bike-Rear-Wheel-Conversion-Kit-Cycling-Motor-Hub-/321679232957?nav=SEARCH). I was also wondering if it is normal for the bike to jolt and stop working when i just pull full throttle i can easily restart the bike by unplugging or turning the key on the battery. Thanks guys. Tell me if you need any info.

 

[dnmun]

i thought it said 25klicks

 

[wesnewell]

Most 36V 500W motors will do 20mph in a 26" rim, so yours probably has a speed limiter made for the Euro market. Some of these limiters are 2 wires connected together outside the controller, while I've heard of some being connected together inside the controller (or just a jumper between 2 pads). You'll have to find out which you have and and take the steps to remove the limiter. The reason your battery is cutting out is probably because it's tripping the bms of the battery pack. IOW's drawing too much current from a stop when you go full throttle. You'd need to replace the bms or bypass it to eliminate the cutting out, or get a battery rated for a higher output.

 

[Ethan102]

I had a feeling it was a limiter. I looked around on my controller once but I wasn't able to find anything obvious that would look like a limiter but i'll take a look when I get home and upload some pictures as well to see if someone can spot something. This is the info about my battery that I just took straight off the listing:

Type: 36V10Ah aluminum case LifePO4 battery pack
Model: EMC3610
Nominal voltage: 36V
Weight: about4.8kg
Standard charge: (0-45 ℃) using 3A to 42V constant voltage constant current charging to the current less than 100mA cutoff (23 ± 2 ℃)
Standard discharge: 2A constant current discharge to 27.5V, 23 ± 2 ℃
Rapid discharge: 5A constant current discharge to 27.5V, 23 ± 2 ℃
Nominal capacity: 10Ah (standard discharge)
Cycle life: standard charge, rapid discharge cycles under the conditions of 1500, the battery capacity is not less than the nominal capacity of 60%
Maximum continuous charging current: 5A
Maximum continuous discharge current: 15A
The maximum instantaneous operating current: 30A
Resistance: (23 ± 2 ℃) ≤ 250mΩ
Battery Box: silver fish 1st aluminum case
Protection system: Built-in
Charger: 36V3A
Size: 360 * 150 * 70mm
Storage conditions: 15 ~ + 35 ℃, relative humidity: 45-75%, atmospheric pressure: 86-106KPa
Use Working temperature: Discharge: 0-60 ℃; Charging: 0-45 ℃

I am pretty sure it is the BMS and some kind of safety measure to keep the battery in working order. My homemade battery has the same problem so I easily bypassed the BMS and it doesn't do it anymore. I guess I will only use it to charge the battery. If it is just the controller could I get a new one that doesn't have a limiter? How would I know if it has one or not? Also I don't know if it a 3-speed switch. What would that look like?

 

[Ethan102]

Alright so i opened up my controller and i found nothing that looks like a limiter wire or a jumper. It is also good to mention that when i first got the kit the first problem i had was that it went backwards as i pulled the throttle. The solution took me a long time but it was very simple. I had to switch the connections of a blue wire and yellow wire leading out of the controller. So when i hook up my bike, i have one blue going into yellow and one yellow going into blue. I don't think that could be affecting anything but who knows? I got some pictures however i don't know how to upload them so I'm gonna need to figure that out.

 

[aroundqube]

I wonder how much the voltage drops from that battery during wide open throttle. There is a correlation between applied voltage and top speed.

 

[wineboyrider]

20-25 mph is a good place to be in the USA and be in the legal sounding range of an ebike depending on what state? Most cops won't bother you if you ride like a bicycle so once you figure out the speed limitation you can move on and get the ebike grin.

 

[wesnewell]

Ref battery. That's a weak battery with a 15A continuous discharge when you have a 26A controller.
When you switched the phase wires, did you also switch the hall wires? Otherwise, the phase sequence is probably screwed up, causing loss of power and a higher amp draw on the controller which in turn draws more from the battery causing the bms to trip. Here's how to find the proper phase sequence.
https://endless-sphere.com/w/index.php/Determining_the_Wiring_for_a_Brushless_Motor
At this point I think that's more likely this speed problem too.

 

[d8veh]

The link in post #1 doesn't work for me, so I can't see what you've got. Can you show a picture of your controller and it's connectors? Does your bike have a LCD. If so, show a photo.

You don't have to worry about any of the above things. I think you're on a wild goose chase. It's easy to check if your bike is speed limited by lifting the wheel off the ground and powering it to maximum speed. Be aware that you sometimes get a bit of overrun. If it cuts in and out at any speed, it's speed limited by the controller. If you can't sense it cutting in and out, do the test twice, once with the battery fully charged and once with the battery nealy empty. If the speed is the same, it's limited by the controller, if there's a significant difference, the speed is limited by the motor.

 

[dogman dan]

Since it shipped from California, it's not likely they'd have chosen a controller with permanent euro limiter, especially with a dd motor.

My suspicion is that the motor is a 6x10 winding.

Often, if you take the covers off, the winding will be written on the motor core. But not always.

 

[Ethan102]

So here is the pictures of my controller. I have to use the link because if i were to upload them here it one picture would take up half the screen http://imgur.com/a/qiT1N#9q8djgJ
I looked at the phase sequencing and sensor wiring and i changed them around a bit but nothing seemed to changed about it.
I also did your little test d8veh and the motor would spin up really fast and then stay constant a constant speed. I know when i am riding the bike as i go down a hill that is slightly faster than 15mph, I can hear the motor stop trying to spin. Also I thought it might be important that i never installed the PAS.

 

[dnmun]

use the VGA setting on your camera. that makes a normal picture 150k.

 

[d8veh]

The PAS should make no difference, but it would show whether you have a faulty throttle.

 

[d8veh]

You need to measure the no-load speed, not just spin it up. Then you need to compare it with the speed when the battery is run down.

Another thing you can try to see whether the throttle is faulty is to short the red throttle wire to the green one with the wheel off the ground, which should make it run at full speed, though some controllers won't allow that, but no harm will be one trying it. If it goes 20 mph like that, you need to fix the throttle.

 

[dogman dan]

Is there a plug on the controller that might be a three speed switch? Lots of possibilities. That might have you locked into 2/3 speed.

Try a different throttle is a cheap one to test.

A different controller could be relatively affordable. But I'm assuming you have no money since you bought the cheapest kit you could find. That does make a defective controller quite possible.

Open the motor to check for winding markings as a last resort.

 

[wesnewell]

I still think he has his phases screwed up. That would explain both his loss of top speed, and the the excessive amperage draw that causes his battery pack to cut out. At this point, I'd take 5 minutes and test the halls for proper operation and then find the proper phase sequence. Although my lipo battery never cut out since I don't use a bms, I've seen the same loss of speed when messing with phase connections.

 

[Ethan102]

Alright, so I will try out the throttle- wheel test before and after a long ride. I will also go mess around with the phase wires some more and if the might do something. For my hall sensor which is the one with 5 wires, should I mess around with the sequencing of the blue, green, and yellow wires?

 

[nutnspecial]

I'm surprised that a kit required mismatched phase colors without being noted in directions etc.

But, on mine I changed the phases (turned out to be yellow/green) until the motor ran fowards, then switched the halls until it ran smooth and had the least draw w/out load (turned out to be the same yellow green I think)

The three way switch is a good idea too, I know my infineon controller was programmed to default to 75% speed if the switch was disconnected.

 

[Ethan102]

I know it is kinda annoying that I had to adjust it to work. So I messed around with the phase wires and hall wires and nothing happened. I tried shorting the red and green throttle wires and it budged a little and then stopped. However, when ever I spaced them apart and put them on my finger so the signal can go through my fingers and the wheel spun until it hit 15mph. I also slowly used the throttle and around the last bit of twisting it it did nothing to help the motor spin.

 

[Ethan102]

Alright so I did the spin test where I do it when it is full and when it is almost out of juice and from I can tell, it seemed to be slightly slower. Now I have no idea if it is the controller, throttle, or motor

 

[nutnspecial]

Hiya, well looking at the ebay kit, there doesn't seem to be a 3 speed switch. Is there any unused connectors from the controller? If so could you describe them?

So I messed around with the phase wires and hall wires and nothing happened.

-Could you please clarify more precisely what you did, and the results? (different combos will affect rotation direction, motor efficiency and speed)
-I doubt throttle is an issue, but you could rule it out by getting another throttle to try (and then have a spare). There are quite a few available from the scooter and ebike sites, to ebay etc. Most are the same hall sensor type that give a varied voltage feedback for controller to assign speed to.
-Others also mentioned photos, they sure wouldn't hurt!

 

[d8veh]

Alright so I did the spin test where I do it when it is full and when it is almost out of juice and from I can tell, it seemed to be slightly slower. Now I have no idea if it is the controller, throttle, or motor

You need to be precise. Use a cycle computer or your LCD to say exactly how fast it went in each situation.. If there's a difference in speed, you're limited by your motor.

 

[Ethan102]

When I messed around with the hall and phase wires I tried different combinations of the wires connecting to different wires. With the phase wires, they either made the motor spin forwards or backwards. I didn't sense any difference in the amps being drawn or anything else. With the hall sensor wires I didn't see any difference either with which order I put them in.
I plan on getting a new controller and throttle to test and see if that might solve any problems. I didn't really like the throttle I have anyways. However is there any specifications I should be looking for such as how many amps I need or how many mosfets? also if the controller has a 3 speed wire where would that connect?
I did upload some pics in my earlier post: http://imgur.com/a/qiT1N#9q8djgJ if you would like me upload different pictures of something else then I will.
My bicycle computer said 15mph as well. Over time it would go up to 15.7 and sometimes it would go down to 14.7.

 

[wesnewell]

You don't have to mess with both the hall and phase wires to find the proper sequence. If you follow the phase chart in the wiki you will get the right sequence. Do you understand the relationship between the hall and phase wires? The hall wire will always fire its associated phase wire. You just need to get the right firing sequence. Out of ~30 motors on the simulator, I can't find a single one that won't do over 15mph on a 36V battery with a 20A controller. Most will do 20+. I also know the wrong sequence will give you ~ 3/4 of your top speed and still feel about right. Testing the throttle is easy. Put 5V on the power input and open it up. You should get ~4.2V on the sense output wire.

 

[nutnspecial]

^^^ good info Wes

Hi, a replacement controller should be matched for the voltage and current range you want to run. I have a programmable infineon from em3ev, and it works great. It does have a 3way switch plug which I use, but if you wouldn't it's programmable to run at whatever speed you want. You will need some computer experience to get the program working. If you want to avoid complication/challenge, save controller replacement till last, and replace with the same one.

If you buy another throttle (or different controller), the plug(s) may not match, so you may need to repin or even replace plugs to match. I would carefully 'hotwire' it first if you just want to test it. If you don't want to mess with plugs, use some butt splices temporarily, or twist the wires, solder and heatshrink. I went with jst connectors for everything on my bike but the power and phase wires, for which I used bullets. If you just want one or two jsts electricscooterparts.com had good prices. Disclaimer- it's challenging to properly crimp them without the right tool. Search topic titles for jst, and you'll see recommends on connectors and tools.

What is going on in this picture right under the shunt and left of the red wire?
http://i.imgur.com/9q8djgJ.jpg

I was told to switch phases until the motor ran forward, then start switching halls till it ran smoothest. It was very obvious on mine but maybe you should use a multimeter to confirm draw when swapping halls. They should definitely make a difference imo. If not, maybe the controller is running sensorless, or the halls are damaged?

That's about the extent of my knowledge on this, but there is alot more if you dig into some different search terms. Good luck and have fun!