Alien bike conversion with pictures and initial impressions

[The Maestro]

The project: to convert my circa 2001 Marin Larkspur hybrid road bike to electric using the 'Alien' 36 volt 700c kit available on ebay. Actually its only available in 26" but the guy who makes them did this as a special for me. He does do 24 volt 700c kits though.

Rationale: The Larkspur is a pretty good bike, weighs 12 kg according to Marin and the Alien kit is claimed to weigh 5 kg, so 17 kg overall - much lighter than any production electric bikes I've seen. I also think it'll have better gears, brakes, headset and other components than most if not all ready assembled electric bikes. The kit cost 440 delivered and the bike was a similar price back in 2001 so I imagine you could pick one up for ~100 quid on ebay or somewhere.

Assembly: Had a couple of hitches. Firstly the new rim did not seem to seat itself at the right angle (i.e. verticall) between the forks. I had to forcibly hold the wheel rim vertical and then tighten the bolts. No big problem but had me wondering why this would be the case? The only other real problem was finding an inner tube suitable for the rim. The inflation valve doesn't reach out far enough because of the funny triangular cross-section of the inner rim (most rims are flatish). Apart from that it was just a case of securing a few components to the handle bars and wires to the frame, putting the rack and battery in place and stuffing all the wires in a small bag along with the controller.

Finished result: Judge yourself from the photos but I think its pretty discreet and looks like a normal bike.

First ride: 10.2 miles journey to work. Didn't go too well, it only seemed to run on the throttle up to 8 mph and maybe assisted a bit if peddling up to about 10 mph. The one good thing I found was being able to leave the bike in a high gear and use the motor to accelerate from a stop and then start peddling. Apart from that it was a very slooooow journey. It was infact so slow that it was hard to balance at times. The 'out of the box' setting for the kit is meant to deliver 15.5 mph on a 26" wheel so I was expecting a little more on a 700c. I was pretty disappointed but didn't give up on it because I thought I might just be the controller settings or something else I could adjust.

Second ride: back from work. Using information from this forum I identified a small variable resistor linking two blue wires coming out of the controller. I cut it off as someone suggested and the performance of the bike was much improved giving around 16/17 mph. Peddling helped add another mph or two but it really wasn't worth the effort peddling more than that. At this point I have to say that it was better than any electric bike I've ever ridden. It had a good cruising speed, was very quiet and went up reasonably steep hills at about 14 mph with minimal peddling.

Battery: At the end of the run into work all lights on the charge indicator were still fully lit. After the ride home only one light out of 6 had gone out. Its hard to say what the batter life would be because the journey into work must have been in some ultra economy mode. I had been peddling lightly most of the way but not really making much effort.

Verdict: It will be a very useful tool for days when I don't feel up to cycling into work under my own steam. Better than any electric bike I've ridden including the Agattu, Lafree, Twist, PowaByke 24 speed commuter However I could wee all over it on the unmodified bike beforehand even on hills and it seemed to limit me to doing about 18 mph where I could generally get up to 25+. I'm wondering if there is any scope for improving the performance more. The seller claims that the derestricted kit will do 20 mph on a 26" wheel so I was expecting similar performance to a Mk 1 Torq on my 700c (i.e. 22 mph on the flat in good conditions). What is the limiting factor? Could I buy another controller that would drive the motor faster or somehow adjust the one I've got some more? Maybe I shouldn't have cut the variable resistor off but just turned it a bit?

Few minor quibbles - thumb throttle makes hand ache after a little while. If you raise your arm to indicate right the throttle will spring back to the off position leaving you peddling in the middle of the road with a heavy bike and no power.

It would be a bit difficult to change the tyre on the front wheel because the wire does not detach from the motor close by. A plug and socket arrangement on the wire close to the hub motor would be a good idea.

Pictures:

 

[john]

Assembly: Had a couple of hitches. Firstly the new rim did not seem to seat itself at the right angle (i.e. verticall) between the forks. I had to forcibly hold the wheel rim vertical and then tighten the bolts. No big problem but had me wondering why this would be the case?

It sounds like the wheel is not fully seated into the drop-outs. This is often the case and you may need to carefully file the drop-outs to get a good fit.

What is the limiting factor? Could I buy another controller that would drive the motor faster or somehow adjust the one I've got some more? Maybe I shouldn't have cut the variable resistor off but just turned it a bit?

If the motor is not running at full speed (as it appears) then I would think that there is still some restriction from the controller. Removing the resistor is probably worth a try but check with other users of this kit.

 

[john]

However I could wee all over it on the unmodified bike beforehand even on hills and it seemed to limit me to doing about 18 mph where I could generally get up to 25+.

I thought these motors ran quite freely as they have a freewheel but you seem to be getting a lot of drag. I wonder what others and Torq users find?

 

[The Maestro]

I thought these motors ran quite freely as they have a freewheel but you seem to be getting a lot of drag. I wonder what others and Torq users find?

I'm not sure if its the exact same motor from the torq although its the same manufacturer and looks similar. I think the wheel does turn quite freely but I suspect that I'm just feeling the extra weight of the bike when I peddle. I think the kit weighs more than the claimed 5kg.

If I lift the front wheel off the ground and put the throttle on full my cycle computer reports its doing 19.5 mph. I guess that the speed goes down to 16-17mph under riding condition on the throttle only due the the motor not having enough power or torque to reach its top speed due to the weight of the bike and rider. It does seem to assist a little up to 19.5 mph.

The battery drain does seem to be very low, its meant to have a range of 20-25 miles in restricted mode, but mine is presumably derestricted but after 10.2 miles to work this morning its still reporting fully charged.

One problem Torq users have reported that I'm not getting is vibration through the handle bars due to the weight of the motor on the front wheel. I don't feel any more vibration than normal. Steering seems to be almost unaffected and it feels like a normal bike.

I

 

[BGElect]

Nice looking kit...

Thanks for the review it came at just the right time, I've just ordered the 24volt 20inch kit for my Dahon folder, I'll let you know how I get on too.

Jusrt for clarity, did you adjust the pot on the blue wires or remove it all togther?

 

[The Maestro]

Thanks for the review it came at just the right time, I've just ordered the 24volt 20inch kit for my Dahon folder, I'll let you know how I get on too.

Jusrt for clarity, did you adjust the pot on the blue wires or remove it all togther?

I removed it altogether. I might stick it back on and adjust it because another forum user said that turning it 3/4 of the way clockwise was slightly better than a full turn.

I'm beginning to think that I've reached the motor's rpm limit based on its internal gearing even though the seller claimed it would do 20 mph derestricted on a 26" wheel.

I might order a motor for a 20 inch wheel. My motor clearly has '26' stamped on it by the manufacturer and looking at their catalogue Suzhou Bafang don't make a 26" motor with a max rpm that will reach 20 mph on a 700c let alone a 26".

 

[HarryB]

Better than any electric bike I've ridden including the Agattu, Lafree, Twist, PowaByke 24 speed commuter However I could wee all over it on the unmodified bike beforehand even on hills and it seemed to limit me to doing about 18 mph where I could generally get up to 25+. I'm wondering if there is any scope for improving the performance more. The seller claims that the derestricted kit will do 20 mph on a 26" wheel so I was expecting similar performance to a Mk 1 Torq on my 700c (i.e. 22 mph on the flat in good conditions). What is the limiting factor? Could I buy another controller that would drive the motor faster or somehow adjust the one I've got some more? Maybe I shouldn't have cut the variable resistor off but just turned it a bit?

This is always the problem with hub motored electric bikes - even though they have a freewheel there is a lot of drag and this limits how fast you can pedal above the motor cut off point. The freewheel disconnects the motor but the wheel still turns some planetary gears and thus the drag. I am surprised that you find it better than any other electric bike including the Agattu - in my experience if you are a fast rider there are not many hub motored bikes that are as good as the Agattu (and Pro-connect etc), the Tongxin motor is very good but that is about it. As many of us have found out there is not much point in having a electric bike if you want to go fast (legally)... but hills are another matter.

 

[The Maestro]

This is always the problem with hub motored electric bikes - even though they have a freewheel there is a lot of drag and this limits how fast you can pedal above the motor cut off point. The freewheel disconnects the motor but the wheel still turns some planetary gears and thus the drag. I am surprised that you find it better than any other electric bike including the Agattu - in my experience if you are a fast rider there are not many hub motored bikes that are as good as the Agattu (and Pro-connect etc), the Tongxin motor is very good but that is about it. As many of us have found out there is not much point in having a electric bike if you want to go fast (legally)... but hills are another matter.

I'm not too sure about the motor drag, if I lift up the front wheel and spin it by hand it will spin very freely. Perhaps not as much as a normal hub but free enough that a miniscule effort would overcome it. I think the extra drag I feel is because of the extra few kilos and the shock factor of going from motor assist to no motor at its cut-off speed. There is also the fact that moving along under throttle or peddling lightly, I am not warming up my body to perform the higher speeds, so when I really go for it I'm not really ready.

But you are correct, I want to go reasonably fast and I have few hills to go up. A normal bike is fine for the route I'm using the bike for, I just want an electric for when I'm knackered, feel my muscles need a rest, got a cold or whatever. I had a brief go on a friend's Agattu and I think its a good bike and probably especially so for hilly country. I found trying to pedal it fast outside of the motor's assistance range not particularly great though. I think its heavier than my bike and it also didn't have toe clips (presumably you could fit one with them though).

 

[HarryB]

I'm not too sure about the motor drag, if I lift up the front wheel and spin it by hand it will spin very freely. Perhaps not as much as a normal hub but free enough that a miniscule effort would overcome it. I think the extra drag I feel is because of the extra few kilos and the shock factor of going from motor assist to no motor at its cut-off speed. There is also the fact that moving along under throttle or peddling lightly, I am not warming up my body to perform the higher speeds, so when I really go for it I'm not really ready.

But you are correct, I want to go reasonably fast and I have few hills to go up. A normal bike is fine for the route I'm using the bike for, I just want an electric for when I'm knackered, feel my muscles need a rest, got a cold or whatever. I had a brief go on a friend's Agattu and I think its a good bike and probably especially so for hilly country. I found trying to pedal it fast outside of the motor's assistance range not particularly great though. I think its heavier than my bike and it also didn't have toe clips (presumably you could fit one with them though).

It is true that the wheel appears to spin freely but in use not so. I can say that having run a Torq (which has the same motor as you have) and it does have a lot of drag and therefore difficult to cycle much above 15-16mph. I am sure the weight comes in to it as well, but is secondary. I did swap the motor for a Tongxin and it made a lot of difference - certainly very easy to cycle up to 22-23mph, the same weight of course and above that speed it felt more like wind resistance that was holding me back. You could of course try a Tonxin motor if you can take a risk with the reliability (it worked for me). I am sure Bob (from sunny scotland I think?) will have one for you to try out. Otherwise you need a normal bike and an electric bike for the days when you have no energy.

 

[The Maestro]

It is true that the wheel appears to spin freely but in use not so. I can say that having run a Torq (which has the same motor as you have) and it does have a lot of drag and therefore difficult to cycle much above 15-16mph. I am sure the weight comes in to it as well, but is secondary. I did swap the motor for a Tongxin and it made a lot of difference - certainly very easy to cycle up to 22-23mph, the same weight of course and above that speed it felt more like wind resistance that was holding me back. You could of course try a Tonxin motor if you can take a risk with the reliability (it worked for me). I am sure Bob (from sunny scotland I think?) will have one for you to try out. Otherwise you need a normal bike and an electric bike for the days when you have no energy.

I still think that on the first day of cycling a lot of the drag was in my mind and a result quick transistions to the ease of assisted riding to unassisted + not warming up. I'll do a proper test at some point, taking the battery off and doing my full route unassisted.

I wonder if Bob from sunny scotland will sell me a Suzhou Bafang motor geared for a 20" wheel seperately hmmm.

 

[oldosc]

I still think that on the first day of cycling a lot of the drag was in my mind and a result quick transistions to the ease of assisted riding to unassisted + not warming up. I'll do a proper test at some point, taking the battery off and doing my full route unassisted.

I wonder if Bob from sunny scotland will sell me a Suzhou Bafang motor geared for a 20" wheel seperately hmmm.

With my Aggatu..I will swear that the motor has drag, when I try to cycle without power, and that the bike is soo heavy, it's a drag.
However I did a few tests on the same hill, with my old mountain bike....it's a lot easier to pedal than the Aggatu...when I loaded the carrier with 12Kilo, oh my, isn't power seductive...

 

[The Maestro]

I don't think the Suzhou Bafang motor has much drag. I cycled the first few miles back from work with no assist and there is one part of the journey which has a slight downhill where I peddle like mad to see how fast I can get it to go. Previous record on the unmodified bike was 31 mph, today did 33.2 . Probably the weight is a slight advantage going downhill. On the flat its a fair bit harder to peddle than before modification and uphill its much harder. Dragging an extra 5 kilos up-hill makes a BIG difference. I also think it has some motor drag but not much. Having said that if you leave the throttle on when peddling over the max rpm then I think it drags a lot more.

 

[Andrew harvey]

If your motor comes with an Ananda controller the pot unplugs.
To get above 20mph you will need the 20" motor in the 26" or 700c rims in my experience.
The 26" wheels I've got give 16 to 17.5 mph with lithium batteries.
I've got one old hack I use for testing with an old Crystalyte controller, remember we use Pulse width modulators to control speed at low throttle settings, but at full throttle they give virtual true DC. The full speed throttle setting is not at maximum current, so higher rated conrollers do not do much to help top speed. Current is highest at 0 RPM and falls as speed increases.
Power output, and thats what we want, is current x back EMF.
Lifting the front wheel of the ground gives your no load speed, this is the point at which the motor is producing only enough power to over come it s inbuilt 'sticktion' (cloggging torque) caused by the interaction of the magnets and the iron laminations within the windings. (this is a simplified explanation).
My Crstalyte controller is rated upto 50V with a 19.?V cut off, coupled to a Cycle Analyst, so as soon as I get to work with 4 fully charged lead acid I might have some fun.
BE WARNED I tried the motor at 48V last week on some semi flat cells and the motor twisted straight out of the dropouts, I've had to make some torque stays.
Also the motor should be about 3.3Kgs on its own, in my experience.

 

[The Maestro]

If your motor comes with an Ananda controller the pot unplugs.
To get above 20mph you will need the 20" motor in the 26" or 700c rims in my experience.
The 26" wheels I've got give 16 to 17.5 mph with lithium batteries.
I've got one old hack I use for testing with an old Crystalyte controller, remember we use Pulse width modulators to control speed at low throttle settings, but at full throttle they give virtual true DC. The full speed throttle setting is not at maximum current, so higher rated conrollers do not do much to help top speed. Current is highest at 0 RPM and falls as speed increases.
Power output, and thats what we want, is current x back EMF.
Lifting the front wheel of the ground gives your no load speed, this is the point at which the motor is producing only enough power to over come it s inbuilt 'sticktion' (cloggging torque) caused by the interaction of the magnets and the iron laminations within the windings. (this is a simplified explanation).
My Crstalyte controller is rated upto 50V with a 19.?V cut off, coupled to a Cycle Analyst, so as soon as I get to work with 4 fully charged lead acid I might have some fun.
BE WARNED I tried the motor at 48V last week on some semi flat cells and the motor twisted straight out of the dropouts, I've had to make some torque stays.
Also the motor should be about 3.3Kgs on its own, in my experience.

Yep I think I'm going to go for the 20" motor but have not had much luck so far contacting the manufacturer about delivery. If I do get a 20" motor do I need a new controller?

When I lift the front wheel off the ground it spins at about 20mph but like you say in practice I get about 16-17mph. I had thought that electric motors delivered the same amount of torque at all rpms and was thinking that maybe the controller was backing off the power at the higher rpms in order to allow a pedelec like assist mode.

Its interesting what you say about the throttle. What would happen if I cut the throttle out and connected with a plain wire? Would I get max power at max rpm? i.e. 20mph ?

 

[john]

Yep I think I'm going to go for the 20" motor but have not had much luck so far contacting the manufacturer about delivery.

Have you contacted ecrazyman? He has supplied these motors in the past.

If I do get a 20" motor do I need a new controller?

You shouldn't need to change this.

I had thought that electric motors delivered the same amount of torque at all rpms and was thinking that maybe the controller was backing off the power at the higher rpms in order to allow a pedelec like assist mode.

Motor torque naturally goes down as speed increases because the back emf causes the current to fall. Nothing to do with the controller.

Its interesting what you say about the throttle. What would happen if I cut the throttle out and connected with a plain wire? Would I get max power at max rpm? i.e. 20mph ?

In a word, No. You generally get max power at 50% of max rpm.

 

[The Maestro]

Just an update. The battery life probably isn't as brilliant as I first thought. It takes ages for the first light to go out but once the second one goes out, the remaining 4 go out within a minute or so and then its completely flat. It does do 25 miles with a derestricted controller and light peddling so I'm still happy with it. People should be aware that the charge meter is misleading though. I was going to use it two days in a row without charging but would have run out of power quickly if I did.