A Very Very Low Cost Electric Bike from Pakistan

[dnmun]

you can open it up and then attach your 60V from your battery directly to the terminals of the input capacitor. the current goes through only half the rectifier diodes now, and maybe the performance will be better if the battery voltage is right on the caps.

 

[numberonebikeslover]

you can open it up and then attach your 60V from your battery directly to the terminals of the input capacitor. the current goes through only half the rectifier diodes now, and maybe the performance will be better if the battery voltage is right on the caps.

Good idea; I was already thinking about opening it but I was so tired of the two days work and it was almost the end of the Sunday, therefore I decided to sleep on it. As I found time I will do that and post a picture of the opened power supply. By the way, the box has such a good look and it is safe from any moisture etc. I think if i opened it, I will make the connection of the dc wire to the input capacitor and close the box again. I hope it is not a sealed one because opening means breaking and that would be a shame. If it could open up nicely and then to close I will use super glue to stick it back after making sure all is good to go.

According to the specs on the power supply i.e. Dc 12 volt 5 amps. What power will it be able to produce because I am also thinking about putting an LED light as well. The LEDs available in the market are either 10 volt 9 watt or 33 volt 20, 30, 40, 50 watts. 10volt 9 watts suits me which costs for Rs. 250/- I will check out if I can source some thing like an LED torch which is more beautiful to look at or a reflector which could accommodate that LEd in useful manner.

The power drawn by Relay is 1.6 amps while 555 pwm is negligible. A 10 volt 9 watt LEd would draw (10/9 = 1.1111 amps) Even If the power supply gives our 3 amps, the LED is good to go with it.

 

[numberonebikeslover]

I Just came back with this LED (picture shows the type of LED)View attachment 10 watt LEd.bmp it is a Chinese brand for sure. The sales man said that it is rate for 10 watt @ 9.5 volts. I tested it with a 10 Ohms resistance and it was a little dim on 12 volt battery. So I decreased the resistance by paralleling another 10 ohms (5 watt) resistance, so, total resistance was 5 ohms. The LED was very bright and drawing about .23 amps. It is so bright that it is not possible to look at it. I am thinking about using a reflector which could make the light concentrate on one large front area on the road. more over the LED will be facing towards the reflector and having its back exposed. This way the light would be reflected from the reflector and not directly from the LED thus it will not make the person facing the light blind.

 

[dnmun]

the little plastic cases are almost impossible to open without breaking them. if you can find a screw that holds the pieces together then you are in luck, except there will still be some of the little plastic hook tabs inside.

but it is better to attach the battery directly to the input of the front end of the charger, and skip the rectifying diodes.

you are running at 1/2 the nominal voltage input and then using half the diodes means you should not try to push more than 1/4 of the output rating. if the diodes burn up then you can still open it and attach to the input cap. just maintain polarity!

 

[fechter]

Sounds like you found a good power supply.
Keep in mind that at 60v input, the output current rating will be a little less than the rating.

Your switch problem can be solved in a few ways. Having two switches is not so bad but a bit inconvenient and leaves the possibility of forgetting to turn one off and slowly draining the batteries. A hidden switch to keep the kids from turning it on is good. A key switch also works for this if you can find one.

Another option is to find a 3 position switch that you turn once to get the power supply on and once more to power the relay. This would be similar to a regular car ignition switch. Usually this is a rotary type switch; 3 position toggle switches are usually off in the middle which won't work.

Another option is to put a linear regulator in parallel with the power supply and have the linear regulator set for a slightly lower voltage. This will back feed the supply long enough to get it started. Once started, the linear regulator does not supply any current since it has a lower output voltage. If you use the zener/FET regulator circuit like I posted with a 12v zener, the output voltage will be around 10v, which should be good enough to get the switching power supply started. Since the linear regulator is only supplying current for a few milliseconds, it won't get hot and won't need a heat sink (unless the power supply fails to start).

 

[numberonebikeslover]

Some re-calculations:

Power of the supply = 12 x 5 amps = 60 watts

As Dunmn said that the power will cut down to ¼ then ¼ x 60 = 15 watt

The supply needs 100 volt minimum to output 60 watt, right?
I am providing it with 60 volts.
So, 60/100 = 3/5 of the original power (60 watts)
i.e. 60 x 3/5 = 36 watts instead of 60 watt

Relay coil draws 1.6 amps @ 12 volt = Power drawn = 1.6 x 12 = 19.2 watt

To check it in practical situation I put the meter on the supply having connected the relay and PWM and noted down the voltage which were complete 12 volt no less. Then put the LED on (along with 5 ohm resistance in series). It lit bright without any decrease in the 12 volt on the meter at all.

In the light of aforementioned calculations, I hope this things gona work and will last. Only time will tell for how reliable it is.

About 3 position switch I already have such on my bike already, because I had to have a key to turn on the bike and having just on off button will enable any neighbour hood kid to turn the bike on at full throttle and that would be devastating. Funny thing is that I never tried to look for what the other wires of that switch do.

I found a beautiful quality reflector in my junk that I keep collecting from time to time. I fixed the LED facing the reflector and made a beam light (concentrated in a circle on the road) the beam travels farther and shows the path in the darkness and is worthy of fixing on my bike. The only problem is that it is just a raw reflector only and no assembly. I have to find a big enough suitable bottle and fix the reflector in the cap of plastic bottle after making a hole in the cap for reflector. Then find a round piece of glass to fix on. That is a task for weekend (Saturday + Sunday).

Sincerely
Naeem

P.S. Post the pictures of reflector later on.

 

[numberonebikeslover]

Hello every one and Assalam-O-Alaykum (meaning; may Allah shower his blessings upon you):

The switching power supply is working fine. I took a ride which lasted not more than few kms but in a traffic jam (stop and start situation for half an hour or so). I got tired of putting my one foot on the ground while leaning back on the seat and found out that it is really very much annoying leaning back while stretching my foot to support the bike. What if bike was a little near to the ground and the height was less it would have been easy. Having that in mind I came back home and started with the recent picture of the bike in computer with the help of MS paint and ACDsee (computer graphics programme) and draw something like this.

It would change the caster angle of front wheel a great deal. Along with this I would need to change the location of the batteries in the back. I would need to change the position of rear suspension, the side stand, the leaning support for back of seat, charging transformer location, etc. This will also put the paddling gear a bit higher than my seat. I think I would need to lower the front suspension a little bit to take care of this problem.

Your useful comments and suggestions will be highly appreciated.

Yours Respectfully
Naeem

 

[amberwolf]

I don't know exactly what result you'd have from doing this, but based on my CrazyBike2 modifications and different fork lengths and tires sizes, I can say that generally when you lower the back end of the bike and/or raise the front, extending the fork angle forward, it tends to make the bike less stable at slower speeds. CB2 presently does not do well below about 10mph, and is best at 12-20mph (and up, probably, but I havent' had the chance to test it over 20MPH since the most recent changes).

But the problem you are having is pretty much why CB2 is so long--so I can have the seat down lower where I can rest both feet on the ground when stopped, and still be able to pedal effectively (well, *I* can't, but a healthy-kneed person could), since the pedals are out forward of me rather than under.

 

[numberonebikeslover]

I don't know exactly what result you'd have from doing this, but based on my CrazyBike2 modifications and different fork lengths and tires sizes, I can say that generally when you lower the back end of the bike and/or raise the front, extending the fork angle forward, it tends to make the bike less stable at slower speeds. CB2 presently does not do well below about 10mph, and is best at 12-20mph (and up, probably, but I havent' had the chance to test it over 20MPH since the most recent changes).

But the problem you are having is pretty much why CB2 is so long--so I can have the seat down lower where I can rest both feet on the ground when stopped, and still be able to pedal effectively (well, *I* can't, but a healthy-kneed person could), since the pedals are out forward of me rather than under.

Thanks for the precious suggestion and specially for sharing your experiences with me.
Keeping that in mind I kept looking at my bike and finally picked up the tools and decided to shorten the front fork and then calculate the amount and point to which I would safely lower the back end of the bike.
View attachment 1
As you might see from the picture the caster angel has reduced and the bike is ready to be lowered from the back end a bit to the limit where we can say its good now.

It took me all day to complete it and I am so tired that I am totally unable to take a ride. I have flue and my throat is terrible and feeling kind of feverish. I hope it may not worst by tomorrow.

Thanks Amber wolf, I don't know what would have I done if it wasn't your useful suggestion. I would have messed it all up. A heartiest thanks goes to you buddy.

Respectfully Yours
Naeem

 

[Rodney64]

Naeem, would be good to see a photo of you on the bike. Maybe you have already.

Regards

Rod

 

[numberonebikeslover]

Naeem, would be good to see a photo of you on the bike. Maybe you have already.

Regards

Rod

Your wish is my command sir. Just took a fresh photo.
Yours Respectfully
Naeem

 

[Rodney64]

Thanks Naeem, looks a very relaxing riding position.

Regards

Rod

 

[numberonebikeslover]

Hello every body and Assalam-O-Alaykum;

Sorry for being away for quite some days for my mother in law in her early 80s passed away a week ago. She was the sweetest lady I have ever known in my entire life. It was indeed a great loss for the family including me for she always remembered me in her prayers along with her children. I was so dear to her that in her last moments she recalled my name several times in the hospital. May her soul rest in peace.

I could not put my last experience with my bike due the aforementioned incident. Here it goes:

In the past I mentioned that I have rewound the motor and it was meant for 72 to 84 volt but to keep it in safe margin I was running it on 60 volts. This decreased the rpm of the motor considerably and therefore decreased the top speed to round about 35 km/hr. In order to increase the speed I put the bike in higher gear and road it. The speed increased but it also stressed out the motor and it got a lot warm. I had to get a blood test report and for that I have to got to the inside of the old city. For a traffic jam I got stuck in an uphill stop and start situation which stressed out my motor so much that it started to produce some kind of smell which was not burning smell but I guess the varnish was cooking and nearing burning up. So I got down the bike and put it again in lower gear and continued the remaining journey. When I came back home I noticed the same smell and when I touched the motor it was noticeably hot. Moreover, the picking power of the bike was so reduced that it scared me a lot. As I checked the batteries I found out that one of the battery is almost dead and has reached 8 volt. The remaining were some where between 11.7 to 11.5.

All this compelled me to think about the rule that I apply for my machine which is Gear down voltage up.

What I understand is that when we gear it down it removes lot of stress from the motor and batteries and therefore the range is increased along with the overall life of batteries and motor.

What do you suggest that how it would benefit my machine and in what way?

Respectfully Yours
Naeem

 

[numberonebikeslover]

I found out that I have a shorter shock absorber than the one fixed in my bike. If replaced with the shorter I can lower the bike's rear end very easily. So I did it by just replacing the shock and also cutting the rear pipe extension, remove the charging transformer and the tilting rod of the back of the seat.

After this mod I took the bike for a spin; to my complete surprise, the bike handling has improved a lot. It is so soft and stable that it seems like I would go to sleep on continuous straight road. It is so comfortable that I can't find words to explain how much. I have to go to bed now but it seems like I would not be able to go to sleep for my joy.

Here are the pictures:

 

[Rodney64]

Naeem, sorry to hear about your mother inlaw and its good that you supported you wife by staying off line. I've geared down to help the motor. The higher your cadenance will help the motor and keep amps down and reduce heat to motor and controller. But I'm sure you know this.

 

[numberonebikeslover]

Naeem, sorry to hear about your mother inlaw and its good that you supported you wife by staying off line. I've geared down to help the motor. The higher your cadenance will help the motor and keep amps down and reduce heat to motor and controller. But I'm sure you know this.

Thanks Rodney; Time is a big healer indeed.

Thanks for sharing the aforementioned facts about Gearing down the motor and voltage up. The thing that confuses me is that the armature was meant for 12 volt and a very high amps. I am going all the way around Higher voltage and lower amps. I hope this motor will stay in one piece cause now I am thinking about adding another battery pack and go for as high as 72 volts. This will definitely increase the rpm the power and the top speed.

Naeem

P.S.
I quote from my e-mail to one of my precious and dear friend on ES. It expresses my love for ES.

In few minutes of desperation when I was unable to access ES I realized that I can't imagine to live without ES. It has become a part of my self now and how difficult and painful it is to be away and not being able to stay in touch. I love this global brotherhood of people from all over the world. Indeed there would be others like me who strongly consider all of us as brothers and sisters. To join hands to change the world with love and peace I understand ES is playing its role which will be no doubt written in golden worlds in the books of history.

 

[spinningmagnets]

Dear Naeem, I am sad to hear of your family's loss, and I wish for you peace and spiritual comfort.

The recumbent style of bicycle is better for most people in many different ways, but it is odd how here in my society, the average person wants a bike with the posture of bicycle racers. If they try a recumbent, they admit that they like it and it is very comfortable, but...they want to fit in, and look like everyone else. When you boldly embrace the recumbent style and use electrical power...you are being a leader instead of a follower.

 

[fechter]

In few minutes of desperation when I was unable to access ES I realized that I can't imagine to live without ES. It has become a part of my self now and how difficult and painful it is to be away and not being able to stay in touch. I love this global brotherhood of people from all over the world. Indeed there would be others like me who strongly consider all of us as brothers and sisters. To join hands to change the world with love and peace I understand ES is playing its role which will be no doubt written in golden worlds in the books of history.

Naeem is referring to a little friendly-fire accident we had. In an effort to slow down the constant attacks by spammers on the forum, we've been banning certain IP address ranges. Unfortuantely, Naeem tried to access the forum using one of the banned IPs and was locked out. I see he's able to post again, but this could possibly happen again. Sorry about that!

The moderator team is constantly trying to improve the anti-spam measures but on some days we just get blasted with so many it's hard to keep up. Anyway, that's a whole separate topic...

Naeem: on your motor, there is certainly a limit to how high you can run the voltage and still have improvement. If the motor RPM goes too high, more power is wasted by wind resistance and iron losses. The trick is to find the best operation range. Motor heating is a good indicator of losses in general. A motor like yours was probably designed to operate around 3,000 rpm. My guess is the losses will start to become a problem above around 5,000 rpm.

If you look at a graph of motor efficiency, the peak is usually close to the unloaded speed. At no load, the efficiency is zero. At stall, the efficiency is also zero. At the maximum power point, the efficiency will usually be not so good. If you can gear the motor so it runs close to the maximum efficiency point most of the time, you'll minimize heating and maximize battery range, but you may need to sacrifice some speed to get this, especially on hills. Ideally, you'd want to be able to change the gear ratio while riding.

Below is a motor graph for a brushed motor. While the scale will be different for your motor, the general shape of the curves should be very close:

 

[numberonebikeslover]

To know the RPM of my motor without having a device I have done a lot of brainstorming and did some interesting calculations.

Thanks to Miles who gave me a hint which helped me a lot in figuring out and solving the entire mystery. It goes something like this as follows:

Please note that the motor is the one which is fixed in my very low cost electric recumbent.

What is the RPM of motor?
i) Gearing reduction:
Motor gear = 10 teeth
Large gear = 48 teeth
Ratio = 48/10 = 4.8
Smaller gear = 20 teeth
Large gear on wheel = 48 teeth
Ratio = 48/20 = 2.4
Total Ratio = 4.8 x 2.4 = 11.52 ……….. (A)

ii) Distance covered by the wheel with one rotation:
Formula = Distance = Circumference x π
= 20 (inch) x 22/7 = 628514 (inches) or 159.642556 cm or 1.59642556 meters ………(B)

iii) RPM of motor while bike traveling at 30 km/hours:
What is the distance covered in one minute?
In 60 minutes distance traveled = 30 km
In 1 minute distance traveled = 30/60 = .5km or (.5 x 1000 =) 500 meters/mint…..(C)

As per equation B one rotation the wheel covers the distance = 1.59642556 meters
Or we can say that:
To cover 1.59642556 meters distance RPM = 1
To cover 500 meters distance the RPM would be = 1 x 500/1.59642556 = 313.1996959
So the rare tire’s RPM is 313.1996959 ………. (D)
What would be the RPM of Motor = A(Gearing Reduction) x D (RPM of rear tire) =
= 11.52 x 313.1996959 =
= 3608.06 rpm of motor at 30 km/hr.

It is important to mention here that the motor is on load and running my bike down the road at 30 km/hrs. One more thing I need to note is the on load voltage of battery.

Please feel free to correct me if I am wrong at any point. Feel free to comment and suggest for any improvement etc.

Naeem

 

[fechter]

One way to get an idea of motor loading is to place your speedometer sensor on the rear wheel and run the motor with the wheel off the ground to find the no-load speed. Then, when you are actually riding, you can note the speed you get and divide to get a percentage of no-load speed. The peak efficiency point will be somewhere around 85% of no-load speed. Maximum power is around 50%.

 

[numberonebikeslover]

It was to my complete surprise when my office crew informed me of Publishing of my Electric bike in the daily news paper: Click the following link:

http://dailyaeen.com.pk/showbiz.html

The newspaper is in Urdu language, I will try and find time to translate all the text in English a little later. For the time being my wife is admitted in the hospital for surgery and I am really very busy.

It is indeed a great honour for me as Registrar, University of Peshawar who happens to be my boss when I went to his office for some permission he interviewed me about my work for half an hour. Every body was so happy about this that the pain and sorrow about my wife's hospitalization got dimmed.

Yours Respectfully
Naeem

 

[Lebowski]

Very cool, congratulations

And in the showbiz section no less

Hope all will be OK with your wife...

 

[Rodney64]

Naeem, its very rewarding when you get recognised. Congrats and hope all goes well with your wife.
Rod

 

[Harold in CR]

Best wishes for you and your wife. Nice to see you get some attention for your Ebike project.

Harold

 

[numberonebikeslover]

Hello everybody;

Added another battery and it almost feels like my bike has two motors. So much power, it scares me. I could not imagine that my bike could ever be able to run at such tremendous speeds. I will try to find a suitable road to test its maximum speed. Actually my breaks have become a lot less efficient for the fact that the speed has increased a lot and also weight increased due to the addition of battery which ultimately made the breaks a lot less efficient. It takes a lot more distance for the bike to completely stop. I was not brave enough to go beyond 50 km/hr this time.

Sincerely
Naeem

P.S. My Wife's surgery (Uterine Fibroid) couldn't go cause her case was a lot complicated and the process was a lot risky. It would be better not to have surgery at this juncture for following reasons:

Mitral valve replacement in 2009
Having chronic atrial fibrillation
on oral Warfarine
HB only 8.1 (normal range 12)

The medical technology is not to the limit where such cases could be tackled in Pakistan without risk and we both are not ready for any risk. God knows what will happen we can just pray at the moment. Thanks God it is not a condition which is life threatening or painful. It is just that she can't get pregnant with that Fibroid and we both decided that we can live with that. the only problem is that by the time it will enlarge.