Review of Argos £285 Folding Bike

[Bonzo Banana]

Don't get confused between engine output and engine input. The Argos bike has 8A input, which is about 200w output under ideal conditions, but when climbing, it would drop to about 144w. Also, I wouldn't trust those figures in that manual. How do they get those figures? They would imply that they use a current control controller, which I doubt they have.

The 24v Decathlon/BTwin folding bikes have 12A controllers, so, even with only 24v, will be the same power as the Argos one.

I assumed the Decathlon figures were input too from the battery to the controller which is more easily measured and just simple DC. Also when you say 12A controller do you mean sustained/rated current or peak/maximum/current limiting figure? I've seen quite a few 250W controllers which are 7A rated and 10-11A peak current. However on some of the 24V 20" wheeled ebikes they have absolutely tiny controllers. Also if a controller is dual voltage but rated to 7A lets say so 7x36V gives you the 250W then that 7A rating still applies to 24V doesn't it so its 7x24 and down to 168W approx?

I've seen so many reviews of 20" folding ebikes over the years and despite their smaller wheels many are criticised for lack of power/torque especially the 24V versions. I'm not defending the lack of power of this ebike just that I think many similar spec ebikes are the same or worse in reality especially when so many others have smaller capacity battery packs and often smaller hub motors on the front. It's common to see 20" wheel ebikes with very low capacity 24V battery packs and very small front hub motors. I think there is a strong connection between battery pack capacity and controller current rating to protect the battery pack. You are not going to get 12A sustained current out of a 120Wh or 144Wh 24V battery pack for very long especially if basic Chinese cells and perhaps only 2 cells in parallel. I mean you have to be realistic, 120Wh battery can only sustain 400W for probably less than 20 minutes likely less than 15 minutes as cells do not produce the same overall energy if discharged faster.

If such an ebike only gives 15 minutes of assistance that is a range of about 3-4 miles based on a average speed of 10-15mph. The discharge rate of ebike battery packs has to be much lower to get up to the claimed 20miles range. Decathlon are stating I think up to 40km range so about 25miles range or about 2 hours riding so their wattage figures seem accurate to provide that range with the supplied battery. Decathlon are quoting 30-50km range with a battery pack of 200-299Wh (yes that is how they list their capacity).

Electric Folding Bike E-Fold 500 - Blue BTWIN | Decathlon

With its 20" wheels, steel frame, adjustable stem and seat post, accessories (pannier rack), and battery life up to 50 km, it's the perfect partner…

www.decathlon.co.uk

 

[Bonzo Banana]

Before upgrading controller , it would be nice to know ehat crappy cells are used and their spec however if they are no name china cells then one would be playing a guessing game.

Most on here who poo poo hub bikes do so because they ahve only tried crappy speed controllers very few try out a decent KT system first where one has far more control on power use.
But as we see a lot on the forum many are only interested in max power offering very little rider input.

Well as Argos are UK based importer they have to adhere to a rigorous certification process so have to obtain the correct certification from the manufacturer which likely needs to have been written by a proper independent certification house and they keep those documents on file in case of inspection by UK authorities. If there was a major ebike recall for their models and they didn't have the correct certification then they would be in a dire situation legally. For that reason most ebikes bought from retailers always have reasonably decent certified cells (even if you don't get that many). I'm not saying they aren't Chinese brand cells but they would need to be from a better factory with decent certification. It's not like buying from Aliexpress where cell quality can vary enormously and some cells may not be certified at all and the only way you can get them to the UK is a personal import i.e. buy from Aliexpress, Amazon marketplace, ebay etc from a chinese seller. I personally would not expect the cells to be too bad, I'm not saying they are great spec or capacity but they should be safe.

 

[saneagle]

I assumed the Decathlon figures were input too from the battery to the controller which is more easily measured and just simple DC. Also when you say 12A controller do you mean sustained/rated current or peak/maximum/current limiting figure? I've seen quite a few 250W controllers which are 7A rated and 10-11A peak current. However on some of the 24V 20" wheeled ebikes they have absolutely tiny controllers. Also if a controller is dual voltage but rated to 7A lets say so 7x36V gives you the 250W then that 7A rating still applies to 24V doesn't it so its 7x24 and down to 168W approx?

I've seen so many reviews of 20" folding ebikes over the years and despite their smaller wheels many are criticised for lack of power/torque especially the 24V versions. I'm not defending the lack of power of this ebike just that I think many similar spec ebikes are the same or worse in reality especially when so many others have smaller capacity battery packs and often smaller hub motors on the front. It's common to see 20" wheel ebikes with very low capacity 24V battery packs and very small front hub motors. I think there is a strong connection between battery pack capacity and controller current rating to protect the battery pack. You are not going to get 12A sustained current out of a 120Wh or 144Wh 24V battery pack for very long especially if basic Chinese cells and perhaps only 2 cells in parallel. I mean you have to be realistic, 120Wh battery can only sustain 400W for probably less than 20 minutes likely less than 15 minutes as cells do not produce the same overall energy if discharged faster.

If such an ebike only gives 15 minutes of assistance that is a range of about 3-4 miles based on a average speed of 10-15mph. The discharge rate of ebike battery packs has to be much lower to get up to the claimed 20miles range. Decathlon are stating I think up to 40km range so about 25miles range or about 2 hours riding so their wattage figures seem accurate to provide that range with the supplied battery. Decathlon are quoting 30-50km range with a battery pack of 200-299Wh (yes that is how they list their capacity).

Electric Folding Bike E-Fold 500 - Blue BTWIN | Decathlon

With its 20" wheels, steel frame, adjustable stem and seat post, accessories (pannier rack), and battery life up to 50 km, it's the perfect partner…

www.decathlon.co.uk

All I can say is that I've ridden many folding bikes, and this one had the lowest power of all of them. Yes, I accept that there are others that also have low power, especially 24v ones. The 24v Cyclamatic had 12A controllers in most versions. IiRC the others were higher.

FYI, the controller's maximum current is always double the rated current, or the other way round, the rated current is half the maximum. Whatever the maximum is, is how much you get when the motor is working in its lower speed range.

You can't calculate the range in the way that you suggested unless you used a current control controller. Even then, how much of the time would you be freewheeling or pedalling above the speed limi? Even below the speed limit, the current is regulated by the back emf, so will be less than the maximum most of the time.

This bike uses speed control and is fairly hopeless because of the low gearing. On level 3, as soon as you pedal, the motor takes it up to around 12 mph, which is about as fast as you can comfortably pedal, so you pedal a few strokes, then freewheel for a bit and repeat. On level 2 it's better, but you only go about 10 mph. It's not easy to explain, but basically along any journey, the power is coming from either you or the motor, not both working together, except on uphill. This will all change in a week or so when I get the new controller. Already, I've changed the gearing to go with it.

 

[Ghost1951]

All I can say is that I've ridden many folding bikes, and this one had the lowest power of all of them. Yes, I accept that there are others that also have low power, especially 24v ones. The 24v Cyclamatic had 12A controllers in most versions. IiRC the others were higher.

FYI, the controller's maximum current is always double the rated current, or the other way round, the rated current is half the maximum. Whatever the maximum is, is how much you get when the motor is working in its lower speed range.

You can't calculate the range in the way that you suggested unless you used a current control controller. Even then, how much of the time would you be freewheeling or pedalling above the speed limi? Even below the speed limit, the current is regulated by the back emf, so will be less than the maximum most of the time.

This bike uses speed control and is fairly hopeless because of the low gearing. On level 3, as soon as you pedal, the motor takes it up to around 22 mph, which is about as fast as you can comfortably pedal, so you pedal a few strokes, then freewheel for a bit and repeat. On level 2 it's better, but you only go about 10 mph. It's not easy to explain, but basically along any journey, the
power is coming from either you or the motor, not both working together, except on uphill. This will all change in a week or so when I get the new controller. Already, I've changed the gearing to go with it.

How did the gearing change go? I think that would make it much better.

 

[saneagle]

How did the gearing change go? I think that would make it much better.

I haven't tried it yet because I stripped out all the electrics while I had the bike inside down so that I can fit the KT controller. Photos coming in 2 mins when I swap to my laptop.

 

[saneagle]

I changed the levers to Tektro ones because one had a long cable to reach the new controller. Legal throttle added to get that instant full power without having to go up and down through the buttons on the LCD4. The buttons on the LCD4 are very awkward to use, but you can just leave it on level 2 or 3, then use the throttle to over-ride whenever you need a bit more power or speed.

The lefthand grip was difficult to get off. I had to heat it. The rest was straightforward.





I now have a complete set of spares if anything goes wrong with yours.

 

[Ghost1951]

I changed the levers to Tektro ones because one had a long cable to reach the new controller. Legal throttle added to get that instant full power without having to go up and down through the buttons on the LCD4. The buttons on the LCD4 are very awkward to use, but you can just leave it on level 2 or 3, then use the throttle to over-ride whenever you need a bit more power or speed.

The lefthand grip was difficult to get off. I had to heat it. The rest was straightforward.

View attachment 59526

View attachment 59527

I now have a complete set of spares if anything goes wrong with yours.

View attachment 59528

This is going to be an interesting project. I think I have all the required tools in my garage in Newcastle for the removal of the screw on freewheel. I have a chain whip and a fancy nut remover thing which I used once about thirty years ago and never looked at since. I can't even remember why I was taking off the freewheel - maybe a mountain bike needing lower gears.

The only other thing we will need to know about these little bikes will be what is inside the battery case. You will have already analysed and to some extent reverse engineered and improved everything else about them.

EDIT:

The downside of making more power available on demand is of course the rather tiny battery that is fitted. 8.5Ahr...... Not much scope for running it hard, is there, unless it is kept local. On the other hand, with more sensible gearing and more control of power draw, the original system may have been wasting power at times.

 

[saneagle]

This is going to be an interesting project. I think I have all the required tools in my garage in Newcastle for the removal of the screw on freewheel. I have a chain whip and a fancy nut remover thing which I used once about thirty years ago and never looked at since. I can't even remember why I was taking off the freewheel - maybe a mountain bike needing lower gears.

The only other thing we will need to know about these little bikes will be what is inside the battery case. You will have already analysed and to some extent reverse engineered and improved everything else about them.

EDIT:

The downside of making more power available on demand is of course the rather tiny battery that is fitted. 8.5Ahr...... Not much scope for running it hard, is there, unless it is kept local. On the other hand, with more sensible gearing and more control of power draw, the original system may have been wasting power at times.

You don't need a chain-whip for a freewheel. You need a freewheel tool, a big monkey wrench and a big hammer.

With the KT controller, you'd be using less power from the battery. The OEM controller only gives max current or nothing. The KT is adjustable, and the throttle allows you to get maximum when you need it, so it should be much more efficient. When you set a 36v KT to level 1, it only gives about 80w (2A), and when you set it to level 2, about 4A. You also have the advantage that you can reduce the current in the settings downwards from the 15A max to as low as 7.5A max, using parameter C5. C5=03 gives max currend divided by 2.

 

[Ghost1951]

You don't need a chain-whip for a freewheel. You need a freewheel tool, a big monkey wrench and a big hammer.

With the KT controller, you'd be using less power from the battery. The OEM controller only gives max current or nothing. The KT is adjustable, and the throttle allows you to get maximum when you need it, so it should be much more efficient. When you set a 36v KT to level 1, it only gives about 80w (2A), and when you set it to level 2, about 4A. You also have the advantage that you can reduce the current in the settings downwards from the 15A max to as low as 7.5A max, using parameter C5. C5=03 gives max currend divided by 2.

I am sure the KT would be a better solution, but is it true that the speed control as supplied only gives maximum power or nothing?

I'll tell you why I ask that - when I am riding above the cut off speed, say in level 2, probably (by estimation) doing about twelve miles an hour, if I slow slightly on an upcoming incline, I feel the power come gently back into the system as the speed controller gets going again, but it is comparatively gentle and quiet. If the incline slows me a wee bit more, I feel a much stronger urge forward and hear more noise. So - just by casual observation, it seems to me as if the speed controller does vary how much output is applied. Something similar seems to happen as the controller switches off in level 2 at about 11 miles an hour. I can feel a good strong urge forward at maybe 10 miles an hour and then it seems to wind back and finally drop off completely. I can sense the point at which it ceases to help and there feelslike a gentle ramping down before that cut off.

Maybe I have missed something here.

 

[saneagle]

I am sure the KT would be a better solution, but is it true that the speed control as supplied only gives maximum power or nothing?

I'll tell you why I ask that - when I am riding above the cut off speed, say in level 2, probably (by estimation) doing about twelve miles an hour, if I slow slightly on an upcoming incline, I feel the power come gently back into the system as the speed controller gets going again, but it is comparatively gentle and quiet. If the incline slows me a wee bit more, I feel a much stronger urge forward and hear more noise. So - just by casual observation, it seems to me as if the speed controller does vary how much output is applied. Something similar seems to happen as the controller switches off in level 2 at about 11 miles an hour. I can feel a good strong urge forward at maybe 10 miles an hour and then it seems to wind back and finally drop off completely. I can sense the point at which it ceases to help and there feelslike a gentle ramping down before that cut off.

Maybe I have missed something here.

That's the one good thing about speed control controllers: As you slow down to go up a hill, they automatically feed in more power without you having to do anything, but the downsides for the rest of the time are too much for me, especially for small-wheeled bikes, where you feel the torque much more.

 

[Peter.Bridge]

I am sure the KT would be a better solution, but is it true that the speed control as supplied only gives maximum power or nothing?

I'll tell you why I ask that - when I am riding above the cut off speed, say in level 2, probably (by estimation) doing about twelve miles an hour, if I slow slightly on an upcoming incline, I feel the power come gently back into the system as the speed controller gets going again, but it is comparatively gentle and quiet. If the incline slows me a wee bit more, I feel a much stronger urge forward and hear more noise. So - just by casual observation, it seems to me as if the speed controller does vary how much output is applied. Something similar seems to happen as the controller switches off in level 2 at about 11 miles an hour. I can feel a good strong urge forward at maybe 10 miles an hour and then it seems to wind back and finally drop off completely. I can sense the point at which it ceases to help and there feelslike a gentle ramping down before that cut off.

Maybe I have missed something here.

As I understand it, with a speed controller, the power supplied by the controller to the motor gradually reduces once you get above the "speed" for that PAS level. So on my Woosh Lishui controller, I was usually pedalling above the "speed" that is set for the PAS levels, as I increased pedalling effort (and went slightly faster), the assist gradually reduced. As I decreased pedalling effort (and the speed reduced), the assist increased.

 

[Bonzo Banana]

I am sure the KT would be a better solution, but is it true that the speed control as supplied only gives maximum power or nothing?

I'll tell you why I ask that - when I am riding above the cut off speed, say in level 2, probably (by estimation) doing about twelve miles an hour, if I slow slightly on an upcoming incline, I feel the power come gently back into the system as the speed controller gets going again, but it is comparatively gentle and quiet. If the incline slows me a wee bit more, I feel a much stronger urge forward and hear more noise. So - just by casual observation, it seems to me as if the speed controller does vary how much output is applied. Something similar seems to happen as the controller switches off in level 2 at about 11 miles an hour. I can feel a good strong urge forward at maybe 10 miles an hour and then it seems to wind back and finally drop off completely. I can sense the point at which it ceases to help and there feelslike a gentle ramping down before that cut off.

Maybe I have missed something here.

That sounds perfectly normal to me, from the controller output, voltage is speed and current it torque so as the bike slows the controller should start lowering the voltage output and increase the current output to give you more torque assistance but at a lower speed (voltage). It certainly sounds like this is how the supplied controller operates. If controllers couldn't do this then a 48V battery setup would only be able to provide additional speed compared to a 36V battery of the same current output but we know that 48V will also be converted down to higher current when necessary to provide more torque too. So even if the ebike has basic stepped assistance speeds for its 3 modes the controller and hub motor are still communicating and the controller is adapting to the speed of the hub motor.

 

[Bonzo Banana]

I changed the levers to Tektro ones because one had a long cable to reach the new controller. Legal throttle added to get that instant full power without having to go up and down through the buttons on the LCD4. The buttons on the LCD4 are very awkward to use, but you can just leave it on level 2 or 3, then use the throttle to over-ride whenever you need a bit more power or speed.

The lefthand grip was difficult to get off. I had to heat it. The rest was straightforward.

View attachment 59526

View attachment 59527

I now have a complete set of spares if anything goes wrong with yours.

View attachment 59528

I'm quite impressed with those water proof connectors on the original controller, Is there a spare connection for a throttle to be added to the original controller?

 

[Bonzo Banana]

This bike uses speed control and is fairly hopeless because of the low gearing. On level 3, as soon as you pedal, the motor takes it up to around 22 mph, which is about as fast as you can comfortably pedal, so you pedal a few strokes, then freewheel for a bit and repeat. On level 2 it's better, but you only go about 10 mph. It's not easy to explain, but basically along any journey, the power is coming from either you or the motor, not both working together, except on uphill. This will all change in a week or so when I get the new controller. Already, I've changed the gearing to go with it.

22mph assistance speed? 22mph sounds great or did you mean 22kph? I must admit I hate a basic cadence system like this. I much prefer a simple throttle where I can just operate when I need assistance it increases range and therefore extends the life of the battery pack. I can ride as much as possible without power and then bail out on the hills etc. I do not see the point of an ebike constantly providing power on the flats and downhill. Torque sensors and throttles seems the far superior options for power control. It would be nice if the controller had a throttle connection for a simple upgrade. For me using this ebike I guess I would have to leave the ebike unpowered most of the time and then select one of the power modes for the hills only, this is much better done with a throttle. I still think the ebike is amazing value though.

 

[saneagle]

That sounds perfectly normal to me, from the controller output, voltage is speed and current it torque so as the bike slows the controller should start lowering the voltage output and increase the current output to give you more torque assistance but at a lower speed (voltage). It certainly sounds like this is how the supplied controller operates. If controllers couldn't do this then a 48V battery setup would only be able to provide additional speed compared to a 36V battery of the same current output but we know that 48V will also be converted down to higher current when necessary to provide more torque too. So even if the ebike has basic stepped assistance speeds for its 3 modes the controller and hub motor are still communicating and the controller is adapting to the speed of the hub motor.

It doesn't work like that at all. The voltage is always the battery voltage. The controller can't adjust it. The controller can only controller the current by switching it on and off through the MOSFETs.

There is another factor that controls the power - the back emf. The faster the motor spins, the higher the back emf. The back emf has the effect of reducing current, but the controller monitors the current, so can compensate within its rules for controlling speed and max current. When the motor reaches a certain speed, there is no longer sufficient net voltage to push the current that the controller allows, and the current ramps down to zero at maximum speed. You would see the effect of that on level 5, but not likely on the lower levels.

Some controllers of either type have algorithms that ramp up the current over a set time period.

 

[saneagle]

22mph assistance speed? 22mph sounds great or did you mean 22kph? I must admit I hate a basic cadence system like this. I much prefer a simple throttle where I can just operate when I need assistance it increases range and therefore extends the life of the battery pack. I can ride as much as possible without power and then bail out on the hills etc. I do not see the point of an ebike constantly providing power on the flats and downhill. Torque sensors and throttles seems the far superior options for power control. It would be nice if the controller had a throttle connection for a simple upgrade. For me using this ebike I guess I would have to leave the ebike unpowered most of the time and then select one of the power modes for the hills only, this is much better done with a throttle. I still think the ebike is amazing value though.

That's a typo. Should be 12 mph. I've now edited it.

Those "waterproof " brake connectors are not particularly waterproof. You can improve them by putting a gob of silicone grease in them to keep the water out. The LCD connector is even worse because the higher voltage in it seems to cause electrolytic corrosion. Always fill them with silicone grease. When you get any corrosion in those connectors, the very thin connector pins break off, then you're in trouble. I prefer to run the wires all the way to the controller, where the connectors are protected. Likewise, I prefer the block connectors because they're easy to repair.

 

[Ghost1951]

As I understand it, with a speed controller, the power supplied by the controller to the motor gradually reduces once you get above the "speed" for that PAS level. So on my Woosh Lishui controller, I was usually pedalling above the "speed" that is set for the PAS levels, as I increased pedalling effort (and went slightly faster), the assist gradually reduced. As I decreased pedalling effort (and the speed reduced), the assist increased.

That is exactly what mine feels like in use. I am sure this is correct.

My only grouse with the thing, and it is no big deal, is that it comes on rather hard from a stand still. I have twice nearly been caught out during low speed manoeuvring in narrow places when I moved the pedals just a smidgen and the thing surged forwards. I can control it by having either of the brakes just slightly on so the motor is killed. Once that becomes second nature, it will cease to be an issue.

I just whizzed half a mile to the shop in the village to get some food and it was incredibly easy, quick and useful. I normally walk to get my supplies but it was just starting to rain, so I shot around on the Argos Bike and was back in ten minutes or so.

 

[Bonzo Banana]

It doesn't work like that at all. The voltage is always the battery voltage. The controller can't adjust it. The controller can only controller the current by switching it on and off through the MOSFETs.

There is another factor that controls the power - the back emf. The faster the motor spins, the higher the back emf. The back emf has the effect of reducing current, but the controller monitors the current, so can compensate within its rules for controlling speed and max current. When the motor reaches a certain speed, there is no longer sufficient net voltage to push the current that the controller allows, and the current ramps down to zero at maximum speed. You would see the effect of that on level 5, but not likely on the lower levels.

Some controllers of either type have algorithms that ramp up the current over a set time period.

That's interesting I thought voltage was directly related to motor speed with brushless motors and current directly effected the strength of the magnetic pull/torque between each movement as it turned but you are saying the same voltage of the battery pack goes through to the hub motor at all times with just the current level varying? There is no voltage conversion in the controller at all? There was a brochure for a mid-drive motor and they claimed that the fact the controller and motor were so close in the motor assembly they could have a very high current connection between the two but the battery pack is external and no better than hub motors so how it can it generate a high current connection to the motor if it isn't converting the voltage down to increase the current level? Confusing.

 

[saneagle]

That's interesting I thought voltage was directly related to motor speed with brushless motors and current directly effected the strength of the magnetic pull/torque between each movement as it turned but you are saying the same voltage of the battery pack goes through to the hub motor at all times with just the current level varying? There is no voltage conversion in the controller at all? There was a brochure for a mid-drive motor and they claimed that the fact the controller and motor were so close in the motor assembly they could have a very high current connection between the two but the battery pack is external and no better than hub motors so how it can it generate a high current connection to the motor if it isn't converting the voltage down to increase the current level? Confusing.

The battery voltage is applied directly to the motor windings as soon as you switch on the battery. It's blocked by the MOSFETs in the controller. The only thing the controller does is open and close the MOSFETs. It's very simple. The controller can adjust the time and frequency that the MOSFETs can open. That's how it controls power.

Bosch motors run at 24v using a 36v battery, so there must be some voltage conversion in the system somewhere. I don't know much about how and why they do that, but maybe it's so they get constant power regardless of the battery state. With the Chinese systems, power goes down as the battery runs down because the voltage decreases.

 

[AntonyC]

The capacitors in the controller and the inductors (phase windings) in the motor act together to some extent like a buck converter so both ways of seeing it are useful, especially 'average' voltage and current. In a basic hub motor system as the bike slows the back EMF from the motor falls, so out of the controller's average output voltage there's more left over to drive more average current through the motor, resulting in more torque. I'm not a 'wood wide web' person so I wouldn't call it communication between controller and motor, it's the physics happening.