A salutary tale

jrmch

Just Joined
Jul 28, 2010
3
0
Hi Forum,

At the beginning of July, I ordered an e-bike conversion kit (Prokit 901 with Pedelec option) from Golden Motor Technology company in China (goldenmotor.com) with a view to converting my mountainbike into an electric bike.

Some two weeks later, the goods had arrived, conversion was complete and I set off to test the bike.
Immediately on switching to 'Pedelec' mode, I observed the following...
1) When starting to pedal, the motor assist can take as long as a complete revolution of the pedal crank before it provides any assist. The actual time taken varies randomly.
2) The amount of motor assist applied bears zero relation to the current pedal torque - it is simply on or off - full power or nothing.
3) This is the dangerous part - When pedalling stops, this system continues to apply motor power for as much as 3 seconds - AFTER pedalling stops. The standard reaction when stopping pedalling is an expectation of the bicycle to slow down - not this one ! The first time I got caught out with this was at a junction. I stopped pedalling but the bike just kept on accelerating. I braked - a fraction of a second later than usual - but I was still one metre into the path of moving traffic. Mercifully it was slow-moving so no disaster but imagine a youngster on the bike and fast traffic. If you're a parent, it's your worst nightmare. And worst still, the child would most likely be blamed for careless cycling when the whole time it would have been the Golden Motor product at fault ! The scenario does not bear thinking about.

I contacted the Golden Motor forum (which seems to be their Customer support centre, but simply got fed rubbish by some contributor - not a company representative.

Then, I contacted Golden Motor directly but did not receive any reply to 3 e-mails - flatly ignored.

I contacted PayPal to raise a claim via their "Buyer protection scheme". They simply said that as the goods had been delivered, they were closing the case. Although PayPal are making money from these transactions, they refuse to take any liability or responsibility.

I've ridden a standard Pedelec bike and it performed accurately and predictably - this conversion kit is a cheap, sub-standard attempt at power assist. The product is dangerous and potentially fatal.

This is simply fraud on the part of Golden Motor - their system is miles short of any Pedelec standard - they well know it - yet they advertise their products as having a 'Pedelec' option. They are dishonest with complete disregard for user safety and should, somehow, be brought to task on this. If the reader cares to have a look round the Golden Motor site, you will see what is supposed to be a Certificate of CE conformity for, I presume, Golden Motor products - a masterpiece of obvious fabrication.

My particular problem is that, living in Switzerland, electric bikes over 500W have to have an official inspection before they can be used on the public roads. I'm sure there's just no chance that something like this will get the nod. I'm already as good as US$1000 out of pocket and no bike and the last thing I want to do is put more hard-earned money into this tale of woe.

I'm of a mind to take this further but thought I drop it in here in case any forum users know anything else about this company or their activities.

Or, maybe any good suggestions as top further tactics ?

Thanks for your time,
jrmch.
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,802
1,537
I honestly don't think it any particular fault of the company.
Yes, the pedelec functions for far longer than is safely or comfortably neccessary, but the same happens with my mass produced Cyclamatic.
The only difference here is that it is very low powered, so when the power is held after pedal rotation stops, then it's not so noticable.
You obviously have a powerful version hub, therefore the extra pull will feel very much exaggerated.
My first build will be in the region of 500w, and i do not intend to fit a pedelec as i want complete throttle control.
Do you really need the pedelec connected?
 

NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10
There is no 'standard' and it's hardly 'fraud' the description of operation you have given is exactly the same as my GM kit and also applies to many commercial bikes as well. The simple magnetic pedelec sensor is a rotational sensor, they all are, it can't sense applied pedal pressure or torque only rotational movement, if the rotating disk is a touch too far away from the sensor sometimes it can give erratic operation. Fitting cutoff brake levers can help with the motor overrun, using these as you approach junctions will kill the motor immediately and prevent any junction overrun.

An alternative is to place a switch in the pedelec sensor cct to enable or disable operation and just use the throttle as necessary. I've done this on my bikes, using the pedelec just for climbing hills where operating the throttle can be a bit of a pain in the wrist and using the throttle to govern assist as I approach junctions....
 

jrmch

Just Joined
Jul 28, 2010
3
0
Thanks for the replies.

Fordulike - The fact that you also have the same 'over-run' does not reduce its danger in inexperienced hands.
Pedelec functionality is a legal requirement for Europe and Switzerland and, properly implemented, is an excellent system.

NRG - Why ever should I have to start modifying a new piece of kit that should perform correctly in the first place ?

You both describe difficulties in controlling these modified bicycles - exactly the point I'm making - it shouldn't be like that !

GM know exactly the standard of Pedelec system they implement - it is crude and potentially dangerous. They knowingly sell a sub-standard product.
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,802
1,537
Thanks for the replies.

Fordulike - The fact that you also have the same 'over-run' does not reduce its danger in inexperienced hands.
Pedelec functionality is a legal requirement for Europe and Switzerland and, properly implemented, is an excellent system.

NRG - Why ever should I have to start modifying a new piece of kit that should perform correctly in the first place ?

You both describe difficulties in controlling these modified bicycles - exactly the point I'm making - it shouldn't be like that !

GM know exactly the standard of Pedelec system they implement - it is crude and potentially dangerous. They knowingly sell a sub-standard product.
And the reasons why i've spent countless hours doing extensive research before parting with my hard earned cash.
Unfortunately a lot of Chinese products are a law unto themselves :(
 

NRG

Esteemed Pedelecer
Oct 6, 2009
2,592
10
GM and many other similar Chinese kit suppliers supply a cheap basic kit that perform as advertised. If you want refinement, a legal well sorted and implemented kit then spend more money and don't buy off Ebay. Have you installed the brake cut off levers that came with the kit? The modification to the pedelec sensor is too give you more flexibility and control, if you don't wish to listen then see my second sentence.
 

tangent

Esteemed Pedelecer
Mar 7, 2010
299
0
fascinating discussion - it sounds as though GM and similar cheap kits provide a starting point suitable for further tinkering and customisation.

How does a "Polished" pedelec work, such as that supplied by Wisper? Is this pressure or cadence sensitive? Does this cut out immediately when you stop pedalling? Do they provide break cut outs?

I am curious since I only have experience of the Panasonic crank drive systems which seem pretty well perfect on pedelec action, which is just as well as they lack a throttle.
 

Straylight

Esteemed Pedelecer
Jan 31, 2009
650
2
The wisper pedelec has a pretty distinct overrun, hence the brake cut-outs as NRG says. Personally I prefer to have the pedelec set in low power mode, which is very low, and use the throttle to apply power as required. I know most kits don't have the low power option, so I'd simply ditch the pedelec in favour of full throttle control.
 

Caph

Esteemed Pedelecer
Feb 29, 2008
440
11
Nottingham, UK
I don't know if Wisper are doing torque measured assist but Powered Bicycles have been doing them since the start of this year across several of their range. I've seen the pedal cranks but not actually tried them out yet. They have a sensor built in to them which detects how much pressure you are exerting. And break cutouts are standard on all bikes and kits even the ProKit according to the installation PDF.

I've got agree with others here. I read through your 3 points and at each one I thought, yeah, mine does that, but I've never thought any of them problematic. The only one that could be considered a problem would be the overrun (they all do it but 3 secs is a bit longer than usual) but then that's what your brake cutoffs are for. Maybe it's the 500W which turns something we don't notice in to something which is a problem for you?
 

Straylight

Esteemed Pedelecer
Jan 31, 2009
650
2
Sorry, missed part of the question re:Wisper, my 905 does not have a torque sensor, just the usual disk of magnets.This doesn't seem to register rotation speed, so is either on or off with regard to the chosen motor power level. Newer bikes have three power levels to choose from, where as mine has only two, though TBH I think even if I had three, I'd still use my current control method, as it's the most responsive.

I can see how the overrun effect could be disconcerting on a more powerful machine, but with practise, think this could be overcome (if the brake switches are anything like mine, then it doesn't take much pressure to cut the motor - I suppose you can almost think of it like the clutch on a car). No-one ever said riding a pedelec was as easy as riding a bike, and I must say that I'm far better at getting the most out of the system now than I was 18 months ago.
 
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tangent

Esteemed Pedelecer
Mar 7, 2010
299
0
By the sound of it then jrmch may be being unrealistic in his expectations. To have a bike behave similarly to a non-powered bike I think you need a sophisticated pedelec system like the Panasonic crank drive ones I am used to or perhaps a low torque system like the Cytronex. Even these have idiosyncrasies that you have to learn to adjust to though. A pedelc system that operates as an off/off switch, with the breaks acting as off switches seems perfectly reasonable but probably takes a bit longer to get the hang of.

I can see jrmch's point though that having 500W or more power that does reduce or stop as you come up to a junction would frighten me.
 

mj8765

Finding my (electric) wheels
May 8, 2009
22
0
Pedelec rules

We found this problem with speed sensing pedelecs. There is an inebriation delay whilst the controller works out what us going on. We refuse to supply pedelec kits without brake cut out levers as we don't like the idea of people not stopping when coming up To junctions.

It does make you think that the European pedelec laws are a bit daft. You must have pedelec function but you do not have to supply cut out brake levers.
 

Caph

Esteemed Pedelecer
Feb 29, 2008
440
11
Nottingham, UK
I tested my bike today.

One and a half revolutions before power kicks in when the motor is first turned on, then following that a quarter of a revolution causes the motor to kick in. So you're doing better than me on that score initially.

My bike kicks in with full power immediately, although obviously it takes it a while to get up to speed. So we're even on that one.

Power continues for between half a second and a second after I stop pedalling. So I'm doing better than you on that score.

So no real surprises. We all are in the same boat but we have different pluses and minuses.
 

Fordulike

Esteemed Pedelecer
Feb 26, 2010
3,802
1,537
jrmch, we all understand your anger at Golden Motor for taking yer cash and supplying a product that doesn't meet your expectations.
We've been a bit negative in supplying you with a solution to your problem, acknowledging that most pedelec systems have the same characteristics.
A summary of solutions, some more acceptable than others, are as follows:

1) Return the kit to Golden Motor for a refund (PayPal claim??) and accept a loss on return postal fee. Then research and buy something that you can live with.
2) Learn to use the brake cut off levers earlier than usual on approach to junctions etc.. If you have a bike with integrated levers and no cut off levers, then there's a mod you can implement using reed switches and magnets. There's a post on this forum highlighting how to do this :)
3) Remove pedelec and have complete user throttle control.
4) Buy a bloody good helmet, just in case :rolleyes:

Not all is lost however, as you have provided invaluable information on the Golden Motor kits. Potential buyers can factor this in with their decision making when choosing which kit to buy :)
 

jrmch

Just Joined
Jul 28, 2010
3
0
bad to worse

Thanks for all your input.

mj8765 - Pedelec assist is supposed to switch off when crank rotation stops - no need for brake levers.

Fordulike - I tried recommendation (1) - GM simply didn't reply to any emails. Only when I raised a PayPal claim did they respond - send the kit back for a refund but cough up another US$ 300 for shipping !! No way.
PayPal said GM had delivered the goods so there was zero assistance in that direction as well.

Regarding recommendation (2) - I am not concerned for myself - I can easily control the bike. My concern is for a youngster who maybe just 'borrows' the bike for a spin not knowing that the motor doesn't switch off when you stop pedalling - comes up to the first traffic junction and then...that's exactly how accidents happen.

However, the foregoing is now purely academic as the controller has packed up. Emails to various GM recipients over the last 2 weeks have produced the single majestic reply of "controller broken" and nothing else. No "Dear customer", no apology for the crap electronics that pack up with less than 2 kilometres 'on the clock', no mention of repair / replacement - but nothing.

I'm US$ 1000 out of pocket with an e-bike that goes nowhere - basically worthless and I can't even get a single meaningful reply from this company. It's no consolation, but the simple fact is I am by no means alone - just read the GM forum - it's bursting at the seams with dissatisfied customers ( goldenmotor.com - Index ).

This company appears incapable of treating paying customers with simply courtesy - just not good enough.
 

Old Timer

Esteemed Pedelecer
Dec 5, 2009
1,279
12
Thanks for all your input.

mj8765 - Pedelec assist is supposed to switch off when crank rotation stops - no need for brake levers.

Fordulike - I tried recommendation (1) - GM simply didn't reply to any emails. Only when I raised a PayPal claim did they respond - send the kit back for a refund but cough up another US$ 300 for shipping !! No way.
PayPal said GM had delivered the goods so there was zero assistance in that direction as well.

Regarding recommendation (2) - I am not concerned for myself - I can easily control the bike. My concern is for a youngster who maybe just 'borrows' the bike for a spin not knowing that the motor doesn't switch off when you stop pedalling - comes up to the first traffic junction and then...that's exactly how accidents happen.

However, the foregoing is now purely academic as the controller has packed up. Emails to various GM recipients over the last 2 weeks have produced the single majestic reply of "controller broken" and nothing else. No "Dear customer", no apology for the crap electronics that pack up with less than 2 kilometres 'on the clock', no mention of repair / replacement - but nothing.

I'm US$ 1000 out of pocket with an e-bike that goes nowhere - basically worthless and I can't even get a single meaningful reply from this company. It's no consolation, but the simple fact is I am by no means alone - just read the GM forum - it's bursting at the seams with dissatisfied customers ( goldenmotor.com - Index ).

This company appears incapable of treating paying customers with simply courtesy - just not good enough.
I know I`m always pushing Alien but at least you can talk to someone and they now do Golden kits so you should be able to get what you want.
 

flecc

Member
Oct 25, 2006
52,763
30,349
I've warned many times in this forum about Goldenmotor, their products and terrible service.

Regardless of Alien handling them now, I'd still advise caution with buying these products. They arrive in unusable condition far too often.
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