Bike runs for 1' then motor cuts out

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mscir   1 mW

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Bike runs for 1' then motor cuts out

Post by mscir » Nov 19 2020 2:05am

My neighbor had a great running ebike that ran on 36V, the controller died, so we bought a controller from AliBaba that we were told would work without hall sensors, just hook up the batteries, display/controlelr, and throttle and it should run without any of the other wires connected. We got the parts, connected it up, the motor runs while the tire is in the air but quickly cuts out when it is on the ground. Also the throttle sticks at full when you release the throttle twist grip sometimes. And the display never shows 36V even though the system is a 36V/48V system. So I tried to return it, the Alibaba site says they respond to those requests in 2 days, well a week had gone by and no reply. So I'm wondering if maybe I'm missing something obvious or someone here has experience with this controller.
i posted a couple of videos of on YT.
https://www.youtube.com/watch?v=qcjbuXbMm28
https://www.youtube.com/watch?v=uWa77QzNDxI
Here are some pictures of the controller, and display
https://i.imgur.com/HRH9SvY.jpg
https://i.imgur.com/pZKtbFJ.jpg
https://i.imgur.com/kvUx77p.jpg

Balmorhea   1 MW

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Re: Bike runs for 1' then motor cuts out

Post by Balmorhea » Nov 19 2020 5:48am

Sounds like a bunk battery to me. Either the BMS is tripping, or the controller LVC is tripping. Could be that the new controller demands more current than the old one, and more than the battery can supply.
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goatman   100 MW

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Re: Bike runs for 1' then motor cuts out

Post by goatman » Nov 19 2020 8:23am

whats the no load amp draw with tire in the air

mscir   1 mW

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Re: Bike runs for 1' then motor cuts out

Post by mscir » Nov 19 2020 11:49pm

Balmorhea wrote:
Nov 19 2020 5:48am
Sounds like a bunk battery to me. Either the BMS is tripping, or the controller LVC is tripping. Could be that the new controller demands more current than the old one, and more than the battery can supply.
We have 3 12V batteries in series, they're pretty hefty, not as big as car batteries but bigger than many motorcycle batteries. I don't think they have a built in BMS. I'll measure the battery voltage with the wheel on the ground and see if I can watch it, the trouble is the bike goes forward about a foot, under drive for less than a second, a voltmeter may not display the lowest V during that period of time, if I had a nice digitial recording oscilloscipe that would be useful. It's a dual 36V/48V system. Strangely the display with the on/pff switch and up/dn buttons never shows any voltage on the battery at all, even though they measure over 36V.

These are the batteries.
https://i.imgur.com/kvUx77p.jpg

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Re: Bike runs for 1' then motor cuts out

Post by mscir » Nov 19 2020 11:50pm

goatman wrote:
Nov 19 2020 8:23am
whats the no load amp draw with tire in the air
I'll think of a way to measure that. I think I have a hefty ceramic low resistance resistor somewhere that I can measure the V drop across while it's in series with the controller current, if I can find that I can do that test.

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Re: Bike runs for 1' then motor cuts out

Post by Balmorhea » Nov 20 2020 4:41am

mscir wrote:
Nov 19 2020 11:49pm
Balmorhea wrote:
Nov 19 2020 5:48am
Sounds like a bunk battery to me. Either the BMS is tripping, or the controller LVC is tripping. Could be that the new controller demands more current than the old one, and more than the battery can supply.
We have 3 12V batteries in series, they're pretty hefty, not as big as car batteries but bigger than many motorcycle batteries. I don't think they have a built in BMS.
Oh, you're using lead bricks... bless your heart. No BMS there, so that possibility is eliminated.

12.3V/battery is not a healthy voltage, and that's even if it's distributed equally among the three batteries. Under load, they could be sagging enough to trip the controller's LVC.

How long did it sit without being ridden or charged?
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E-HP   1 MW

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Re: Bike runs for 1' then motor cuts out

Post by E-HP » Nov 20 2020 9:39am

Your controller may think you're using a 48v battery (and the corresponding LVC), so even a small sag can cut out power.

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Re: Bike runs for 1' then motor cuts out

Post by docw009 » Nov 21 2020 12:27am

Can't tell from the video. WIth no load, is the wheel spinning pretty fast? Hardly looks like it's turning in the video, DOes the speddometer work?

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Re: Bike runs for 1' then motor cuts out

Post by mscir » Nov 24 2020 12:34am

The speedometer doesn't show any change when the wheel rotates, I thought that was because there were no Hall sensors. Do you know if it should show some sort of speed display anyway? The controller is supposed to be 36V/48V and there doesn't appear to be a way to change the display to select one voltage or the other, it's not shown in the paperwork that came with the display, the off on works and the 5 "gear" mode selection works. Maybe there's a jumper on the controller to select 36 or 48V but there is no paperwork with the controller, the seller just referred me to the graphic on the sales web site which I left a link to on imgur, I didn't see anything indicating a jumper for 36V / 48V operation. It's frustrating not having paperwork. I will never buy anything from that seller again.
Last edited by mscir on Nov 24 2020 3:25am, edited 1 time in total.


mscir   1 mW

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Re: Bike runs for 1' then motor cuts out

Post by mscir » Nov 24 2020 3:32am

E-HP wrote:
Nov 24 2020 2:13am
maybe try adjusting C12
https://download.elecycles.com/manual/D ... isplay.pdf
Thank you very much for that, that is FAR more detailed than the paperwork that came with the controller!

We'll adjust C12 and see what happens!

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Re: Bike runs for 1' then motor cuts out

Post by mscir » Dec 09 2020 7:25pm

E-HP wrote:
Nov 24 2020 2:13am
maybe try adjusting C12
https://download.elecycles.com/manual/D ... isplay.pdf
We reset it to factory defaults then changed C12 to the lowest V, IIRC it was setting 0, -2V below default, the bike runs a little and stops. I think the controller is defective, the last controller worked great. I'm trying to return it.

NOTE:
I opened a return request with PayPal, then read on their site that they suggested I resolve it with the seller. The return page said i could always open the return request again, so I canceled the return request.
The AliBaba site ignored my requests for a return for about 2 weeks.
I tried to re-open the return request with Paypal, the site wouldn't let me due to an unspecified error, I called customer service, they said I could reopen the return request but not for funds, once you cancel a request one time it is forever closed to fund reclamation.
So if you use PayPal and start a return request DO NOT CLOSE IT. THE RETURN PAGE WORDING IS HIGHLY MISLEADING, you have to read the fine print of the user agreement to find this, which of course I didn't do.
I'm going through my Chase bank trying to get a return which can be very slow.

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E-HP   1 MW

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Re: Bike runs for 1' then motor cuts out

Post by E-HP » Dec 09 2020 8:03pm

mscir wrote:
Dec 09 2020 7:25pm
E-HP wrote:
Nov 24 2020 2:13am
maybe try adjusting C12
https://download.elecycles.com/manual/D ... isplay.pdf
We reset it to factory defaults then changed C12 to the lowest V, IIRC it was setting 0, -2V below default, the bike runs a little and stops. I think the controller is defective, the last controller worked great. I'm trying to return it.

NOTE:
I opened a return request with PayPal, then read on their site that they suggested I resolve it with the seller. The return page said i could always open the return request again, so I canceled the return request.
The AliBaba site ignored my requests for a return for about 2 weeks.
I tried to re-open the return request with Paypal, the site wouldn't let me due to an unspecified error, I called customer service, they said I could reopen the return request but not for funds, once you cancel a request one time it is forever closed to fund reclamation.
So if you use PayPal and start a return request DO NOT CLOSE IT. THE RETURN PAGE WORDING IS HIGHLY MISLEADING, you have to read the fine print of the user agreement to find this, which of course I didn't do.
I'm going through my Chase bank trying to get a return which can be very slow.
Sorry to hear that. I haven't bought from Alibaba, but have used Aliexpress. The one time that I had to file a claim, I eventually got a refund, but it took a long time, and emailing back and forth was slow. Good luck. Hope it works out for you.

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neptronix   100 GW

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Re: Bike runs for 1' then motor cuts out

Post by neptronix » Dec 09 2020 8:34pm

A multimeter would show you the reason. You're likely drawing too many amps and voltage is sagging to 32v or below. That's approximately the low voltage cutoff for an average 36v controller.

12.3v x 3 batteries is 36.9v .. which.. in a 36v lithium battery, is nearly dead.

Your display shows a dead battery.. so it's thinking your battery is dead. Then you hit the throttle and the controller thinks it's dead-er and cuts off the power.

If you adjust C12 to 0 and the controller is specified for 36v, then the low voltage cutoff is 34v, which your battery easily drops below the second you hit the throttle.

Get a multimeter out and you will probably see i'm right.

C12 = 4 is probably a more appropriate setting.

This KT controller may not be capable of a proper LVC setting for your battery.
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mscir   1 mW

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Re: Bike runs for 1' then motor cuts out

Post by mscir » Dec 10 2020 3:57am

Thanks neptronix,

We tried all 6 wiring combinations for the 3 motor power wires, no change in behavior was noted when the wheel spun (whether in forward or reverse), it always turned off quickly.

It makes sense that you think using lead acid batteries with this controller is a mistake. That's what the bike came with, it used to drive great with the old controller, but my neighbor didn't do any long trips. It had good torque with the old controller too, the front wheel would spin a little if you gave it full throttle from a dead start, really torquey.

The controller is supposed to detect the voltage automatically, pg 5. says (literally) "24V, 36V, 48V supply voltage can automatic identification and be compatible."

It seems strange that the voltage display is always zero even if we have fully charged batteries at turn on before placing further demands on the batteries. We tried adding a 4th battery in series but the behavior was the same. That makes it sound like there is a very basic problem somewhere, that's why I thought the controller was broken, even set at C12=0 with the battery voltage well above 28V the battery charge indicator showed nothing, that made me suspect that the controller was broken.

When we first cycled through the settings C12 was set to 4, the chart shows a low V condition for that setting to be 30V, we thought setting it to 0, "Default value - 2V", would let it run above 28V. It runs with the wheel in the air and with the wheel on the ground but being held up enough that there is a lot of friction but not the full weight of the bike and rider, but it stops quickly when the full weight is applied to it. So it sounds like you're right, this controller with these batteries is a bad match.

I'm going to eat the controller loss since I recommended it and I screwed up the paypal refund, and to quote Jericho Green, "I'm out!" LOL

Thanks to everyone who contributed, I appreciate your time and thoughts.
Mike

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E-HP   1 MW

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Re: Bike runs for 1' then motor cuts out

Post by E-HP » Dec 10 2020 8:14am

mscir wrote:Thanks neptronix,

We tried all 6 wiring combinations for the 3 motor power wires, no change in behavior was noted when the wheel spun (whether in forward or reverse), it always turned off quickly.

It makes sense that you think using lead acid batteries with this controller is a mistake. That's what the bike came with, it used to drive great with the old controller, but my neighbor didn't do any long trips. It had good torque with the old controller too, the front wheel would spin a little if you gave it full throttle from a dead start, really torquey.

The controller is supposed to detect the voltage automatically, pg 5. says (literally) "24V, 36V, 48V supply voltage can automatic identification and be compatible."

It seems strange that the voltage display is always zero even if we have fully charged batteries at turn on before placing further demands on the batteries. We tried adding a 4th battery in series but the behavior was the same. That makes it sound like there is a very basic problem somewhere, that's why I thought the controller was broken, even set at C12=0 with the battery voltage well above 28V the battery charge indicator showed nothing, that made me suspect that the controller was broken.

When we first cycled through the settings C12 was set to 4, the chart shows a low V condition for that setting to be 30V, we thought setting it to 0, "Default value - 2V", would let it run above 28V. It runs with the wheel in the air and with the wheel on the ground but being held up enough that there is a lot of friction but not the full weight of the bike and rider, but it stops quickly when the full weight is applied to it. So it sounds like you're right, this controller with these batteries is a bad match.

I'm going to eat the controller loss since I recommended it and I screwed up the paypal refund, and to quote Jericho Green, "I'm out!" LOL

Thanks to everyone who contributed, I appreciate your time and thoughts.
Mike
Since it’s a KT, I would try unplugging the display harness and jumpering the wires to turn on the controller to see if you can run without it. That might help isolate the issue.


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