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Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 03 2019 3:00pm
by maitilupas
perfect , going to do that, thanks allot for your support chito!

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 03 2019 3:30pm
by Chito
maitilupas wrote:
Nov 03 2019 3:00pm
perfect , going to do that, thanks allot for your support chito!
You can also arm the bottom bracket without the spring, which will only work the pass sensor and not the torque + pass sensor. I tell you if you can't find material to make a new spring. You can arm without spring and calmly look for a suitable material, then you put it

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 03 2019 5:03pm
by fifthbro
Chito wrote:
Nov 02 2019 7:33pm

What is happening to you is due to an incorrect offset between the sensor magnets. When you feel the intermittency is when you lower the left pedal because the natural torque of the bottom bracket axis helps to further offset the magnet that is more central, however when you lower the right pedal, it does not contribute to offset the magnet due to the torque of the axis because chain transmission is more direct. If you also feel loss of power when you lower your right foot it is because the angular offset between the magnets is very large.
The solution to this problem is to rotate the magnet (the one inside) a little (VERY LITTLE) counterclockwise if you look at it from the side of the chain. Or rotate the magnet that is outside, in favor of the hands of the clock, but it is more difficult.
Thanks a lot, will give it a go and experiment a little bit. Sounds like there is no point bothering with software update that I have been advised by the seller.

Also, given some of the problems with the spring described in few recent post, I can foresee and opportunity for someone to offer an aftermarket replacement.

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 04 2019 9:18am
by giannidipie1
my experience: I bought the 36v engine a few days ago.
As soon as I started pedaling on a slightly steep climb and applying more force on the pedal, I felt some engine power drops, as if the current suddenly stopped and then resumed.
Could this problem be due to an incorrect sensor magnets allineament?

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 04 2019 4:23pm
by Chito
giannidipie1 wrote:
Nov 04 2019 9:18am

Could this problem be due to an incorrect sensor magnets allineament?
Yes
what happens is that the torque sensor works with the angular offset between the magnets, the more force you apply to the pedals, the more angular offset there is between the magnets and the motor helps more. But if the angular offset is very large, the motor stop. This is due to the following: the sensor registers a pulse every time there is a change of poles in the magnet; there is a reference magnet and a measuring magnet, when force is applied, the measuring magnet gives a delayed pulse with respect to the reference magnet and this is used for torque calculations, but if the delay is very large, the sensor registers the Pulse of the previous pole shift as the true one (in the measuring magnet), so the sensor interprets that the measuring magnet is advanced rather than delayed so it is interpreted that force is not being applied. That is why the measuring magnet has to be advanced a little to prevent this from happening

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 04 2019 4:59pm
by Chito
Therefore, it is necessary to advance the measuring magnet a little to prevent the above described from happening.
In the video that was shared previously, it is indicated how the magnet should be rotated

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 05 2019 2:51am
by stancecoke
This doesn't seem to be a reliable system. Broken springs, displaced magnets....
A good idea, but badly implemented.
Has anyone a proper working system? :-)

regards
stancecoke

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 05 2019 3:02am
by maitilupas
stancecoke wrote:
Nov 05 2019 2:51am
This doesn't seem to be a reliable system. Broken springs, displaced magnets....
A good idea, but badly implemented.
Has anyone a proper working system? :-)

regards
stancecoke
nothing from China is reliable.
BUT:
This motor is small ,
this motor is silent,
this motor doesnt heat up,
this motor doesn't hang under the bottom of the bike
this motor has allot of torque.

Displacement magnets in the axle or a spring can be upgraded.

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 05 2019 3:22am
by casainho
maitilupas wrote:
Nov 05 2019 3:02am
stancecoke wrote:
Nov 05 2019 2:51am
This doesn't seem to be a reliable system. Broken springs, displaced magnets....
A good idea, but badly implemented.
Has anyone a proper working system? :-)

regards
stancecoke
nothing from China is reliable.
BUT:
This motor is small ,
this motor is silent,
this motor doesnt heat up,
this motor doesn't hang under the bottom of the bike
this motor has allot of torque.

Displacement magnets in the axle or a spring can be upgraded.
Maybe they can improve this motor over time, maybe they read this thread and see the users issues.

TSDZ2 had also silently being improved over time, with changes that really make difference like reducing the motor noise and more robust torque sensor (mainly in side play of the axle). We can find in the market the repair parts and the different versions of the gears, etc.

The thing is that DIY mid drive motors may be stopped in development, seems the popular ones are not for DIY (I mean even Chinese). So let's hope that at least they are willing to invest more to improve this issues.

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 05 2019 3:40am
by giannidipie1
Displacement magnets in the axle or a spring can be upgraded.
could you better explain what you mean by upgrade?

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 05 2019 3:47am
by maitilupas
giannidipie1 wrote:
Nov 05 2019 3:40am
Displacement magnets in the axle or a spring can be upgraded.
could you better explain what you mean by upgrade?

You can offset the magnets and upgrade the spring , seems that this spring (it just a metal part) but is week and tend to break on some users like me.
Chito produced this in 2 thinner parts. I would go for a good quality harden steel

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 05 2019 4:21am
by giannidipie1
maitilupas wrote:
Nov 05 2019 3:47am
giannidipie1 wrote:
Nov 05 2019 3:40am
Displacement magnets in the axle or a spring can be upgraded.
could you better explain what you mean by upgrade?

You can offset the magnets and upgrade the spring , seems that this spring (it just a metal part) but is week and tend to break on some users like me.
Chito produced this in 2 thinner parts. I would go for a good quality harden steel
:thumb: I will try to rotate the magnets and make new more solid spring. I let you know the result

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 15 2019 12:46am
by Dorph
Anyone know if this motor will work with pedal-brake systems (gear in hub)?

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 15 2019 12:56am
by maitilupas
Dorph wrote:
Nov 15 2019 12:46am
Anyone know if this motor will work with pedal-brake systems (gear in hub)?
Yes of course you can adapt that but probably you need to run the ebrake wire from the front of the bike till the rear wheel where you can adapt a sensor on the moving part of the brake hub

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 16 2019 9:22pm
by Chito
Dorph wrote:
Nov 15 2019 12:46am
Anyone know if this motor will work with pedal-brake systems (gear in hub)?
if you mean the brake system that works when you turn the pedals back, the answer is no, because when you rotate the pedals in an anti-clockwise direction with this engine, the chain does not move

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 16 2019 9:38pm
by casainho
Chito wrote:
Nov 16 2019 9:22pm
Dorph wrote:
Nov 15 2019 12:46am
Anyone know if this motor will work with pedal-brake systems (gear in hub)?
if you mean the brake system that works when you turn the pedals back, the answer is no, because when you rotate the pedals in an anti-clockwise direction with this engine, the chain does not move
You can use TSDZ2 as there is a specific version for that kind of brakes, coast brakes.

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 26 2019 4:57pm
by fifthbro
I am trying to replace the spring and move the magnets as per suggestion from Chito. However, I am unable to remove the bearing that seems to be stuck to the shaft. All DIY methods failed, does anyone have any good advice on how to detach it to get to the screws underneath?

Image

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Nov 29 2019 1:40am
by Chito
there are holes in the back of the piece of the image. through those holes you can push the bearing

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Dec 01 2019 11:46am
by Metaller
I realized that one of the magnets sometimes shifts in the torque sensor, which leads to problems... it is not likely that the sensor spring always breaks. If anyone is working out the firmware here - it would be good to add a software adjustment to this sensor by introducing an adjustable software delay of the signal from one of the magnets. Add a timer with a shift constant to the interrupt processing, then it would be possible to fine-tune the sensor without disassembling the engine. Image

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Jan 22 2020 3:18am
by giannidipie1
I bought a new 48v engine from Okfeet. This new version goes very well and does not suffer any problems because lately the shaft has been much improved.
Initially I had problems but with the support of both Skye (Okfeet) and Lingbei everything was fine. The motor is light, quiet and very powerful, and is very very quiet. :thumb:

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Feb 03 2020 3:28pm
by Griepje
I’m thinking of buying a lingbei too, what is your range on low assist?
What battery capacity should i need for a 100 mile range?

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Feb 04 2020 1:44am
by amberwolf
what would your power usage in wh/mile be?

if you don't know that, then:

what is your weight (bike and you and anything you would carry), terrain, wind, speed, riding style (lots of stops/starts, hard acclerations, or long continous rides at one speed, etc), and how much assistance do you need from it, and are you going to be shifting gears appropriately as needed, or always riding in one gear, etc etc. ?

knowing those will help you figure out how much power you need, which will help you know how much you'll use each mile, which will help you know how much you'll need for a hundred of them.

as an example, typical riding around at 20mph will probably take an average rider on flat terrain around 10wh/mile.

the same but at 10mph would probably take less than 5wh/mile, because there's a lot less air resistance at lower speeds.

the same but at 25mph, for the same reason, would probably take up to 20wh/mile.

if there's a lot of stops and starts, or hills, you might double the wh/mile figure.

let's go back to that first scenario, 10wh/mile. if that's all you use, then 10 x 100 miles = 1000wh for a battery, which for a 48v battery is around 21ah, minimum. that's kind of a big battery, but not huge. would probably weigh less than 17-20lbs, depending on chemistry and casing, and probably be around the size-ish of a 50cal ammocan (shape could vary a lot depending on cell type used).

always better to use a bigger battery than you need, because:
--as it ages, it'll have less capability and capacity. some cell types age faster than others, and depending on their usage it can be even worse.
--if you end up with headwinds or detours, you'll need more capacity to give you the same range.
i usually go with 20-30% extra, at least, for just-in-case. more, if your conditions and routes are more variable, maybe up to another 50%.

so you might need 1300-1500wh if you needed a lot extra just-in-case capacity. 1500wh would be around 32ah. this is a pretty big and heavy battery, getting to the 25-30lb range.

if your riding used 20wh/mile, you'd need a battery twice as big as the above estimates.

if your riding uses a lot more, then a much bigger battery.

if a lot less, then a much smaller one.

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Feb 04 2020 2:03am
by dodjob
The lingbei aren't long range mids. They tend to have a high consumption at lower assist level.
I use them strickly on cargo now. They are absolutely perfect for this.
For reference, with a 800wh battery the range on a emtb used on streets is about 70-80km. (At 25-30kmh)
With a 500wh, and use VERY conservatively, it's about 60-70km. As mentioned before, they are not made for this, I still don't know why they did this, that would make it the perfect adaptable mid. I really love it :)
Hope that helps!
Hadrien

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Feb 04 2020 7:30am
by SlowCo
Griepje wrote:
Feb 03 2020 3:28pm
I’m thinking of buying a lingbei too, what is your range on low assist?
What battery capacity should i need for a 100 mile range?
That depends if you live in Limburg or the flatter parts of the Netherlands. :wink:
If you're looking for a mid drive with torque sensor you should also look at the TSDZ2: http://www.pswpower.com/ven.php?cargo.2017-2s-gaym
There is a lot of support here on E-S including developed firmware (smoother function and up to 750W hot rodding) for that unit:viewtopic.php?f=28&t=79788

Re: New "Lingbei MM28.250 torque sensor mid drive"

Posted: Feb 04 2020 11:38am
by dodjob
@slowco that's an excellent proposition. The tdsz2 is very nice for range. It's pretty noisy and lack torque but it does make wonders for battery consumption :)