Home Electrical/engineering Lev Project

[greenwanderer108]

Looking for fiberglass manufactuers/molders as well as solar cell suppliers in Bangkok :

I'm working on a home project to convert my bicycle to a LEV (light electric vehicle)

Sure, I know there are a few local manufacturer/distributors of electric bikes / LEV (i.e. EV Thailand , Ecobrand, and smile car).

The EVThai's Wello is probably the best set up and value for for it's removable battery pack (practablility for someone living in a small condo/apartment) and lower cost (14,000 baht compared to Ecobrand Harrier at almost 30,000!!).

Anyhow, the point was that I'd rather do the conversion myself rather than just pay some company for their product of which I'd be at mercy after the warranty expired in a year. The electronic technology for LEV's are quite simple in that they are roughly three-four part circuits (i.e. motor, motor control / drive system, and rechargeable power pack)

So, for this particular project, I've already added an extra freewheel gear to the back wheel where the disc brake used to sit. This gear on back left wheel will be spun by a 250-350 watt DC motor sitting over the rear wheel.

Aside, from acquiring the proper PWM motor controller and drive system (which will use the motorcycle handle grip type throttle attached to some type of potentiometer/springed adjuster rig on the controller),

I have to build a custom compartment to protect the motor and (detachable) power/battery pack from water/weather/and other short-circuit dangers. This particular compartment will be screwed/braced firmly over the back wheel.

I've decided that a strong fiber glass (like that used for boats) will be the best route to go for this. Like I said, the compartment would most likely be two parts (battery back and motor) which will snugly be bolted/braced onto the steel frame over the back wheel.

So I would like to know if anyone knows of a fiberglass manufacterer/producer in Bangkok that can mold such a compartment to specific specs / dynamics? I'm not so familiar with fiber glass molding techniques / technology, but understand the process isn't too complicated, so there must be many shops/specialists.

Eventually, down the road I will add a solar recharging circuit to top off the battery pack. So, does anyone know of a supplier/manufacter/importer of small photvoltaic cells (solar panels) in Bangkok? I'm not looking for large panels to power a house, but smaller ones that can be wired in series-paralell for smaller recharging circuits/projects (i.e. 1.5 to 12 volt)?

Thanks in Advance

[Tywais]

So, for this particular project, I've already added an extra freewheel gear to the back wheel where the disc brake used to sit. This gear on back left wheel will be spun by a 250-350 watt DC motor sitting over the rear wheel.

Aside, from acquiring the proper PWM motor controller and drive system (which will use the motorcycle handle grip type throttle attached to some type of potentiometer/springed adjuster rig on the controller),

Can't help you on the panels. However I have been working on a project at the university to convert a bicycle to be fuel cell driven (purely a proof of concept vehicle). We also incorporate a 250 W DC motor for main drive. I designed the PWM drive controller if you are interested in the schematics. It is PIC microprocessor based and can supply you with the code also. The throttle is easy to get and is a magnetic sensor type (pretty standard on electric bikes here) rather then a pot, more reliable and insensitive to the weather. The price is a couple hundred baht. A microswitch is attached as the brake feeding the controller, however it does not actually brake the bike but disconnects the motor. For DC braking, would need a bipolar control system (complex).

[The_Other_Mac]

Electric tuk-tuks! That'll be the day...

Some of those commercial products look, well, less daft than I expected. I see that scooters have a range of around 80km, which sounds usable for most people. What's the catch? Are they absurdly expensive? I can imagine that many people would be put off by the lack of noise...

And what about the electric, er, push-bikes, how does that work? Do they recharge while you're freewheeling? Do you use battery power to help you up those hills, or for cruising on the level?

P.S. Just a design comment, you mention putting the battery pack over the back wheel, but I notice all the commercial designs put it as low as possible. Might be to keep a low centre of gravity for stability - less work on your arms.

Edited October 9, 2005 by The_Other_Mac

[greenwanderer108]

tywais,

yes please do email me with the details about the schematic for this circuit you designed. So this brake switch, you mention simply breaks the circuit? Did you incorporate a lockable key switch to activate the control circuit?

If anything, I want to know as much about PWM circuits as possible as my basic knowledge is quite limited. Ultimately, I want to convert a 25 foot river transport boat's deisel system to be electrical using the original drive/steering system. Obviously, this is a more advanced project, so the bicycle conversion will be my crash course into electrical drive/control systems, as it's basic enough.

So, what about this magnetic sensor type throttle? Yea, the potientiometer probably wouldn't exactly be practicle for a bikes' control speed, but I'm afraid I understand next to nothing how a magnetic sensor throttle works. Will have to do some more education/research soon. In the meantime, how about that schematic?

BTW, what University do you study (or teach)? Tell us more about your project, sounds interesting!!

The OTher Mac,

About the design, as far as putting it on the back wheel, it only seemed practicle for a beginner jerry-rig design, as there is the frame extension which serves as a back seat (which ofcourse with a chain-gaurd will still serve as a seat for light riders), otherwise, by adding the components on the frame somewhere, I'd have to weld some extra brace for the battery pack. These commercial designs use a special japan/china imported motor specefic for e-bikes that mounts right on the back wheel with no need for a chain and gear. I wouldn't even know where to acquire such a motor. However, just standard 24 volt 250-300-500 watt motors are abundant and easy to find all around Bangkok.

Anyhow, I figure, the motor and battery weight will be roughly 20 kgms max and that's not too much to hall around on the back when my battery was low/dead. Less than half of what I'm used to halling around my girlfriend. Though I imagine with her weight on top of this will be another story, thus the frame/compartment will have to be sturdy, which I'll probably consider spokless wheels later on.

80 kph??? Really, which maker? I didn't survey all the costs but EVThais motorbikes seemed pretty efficient. Though I think the Lynux was there best one which was rated like 50 kph max speed, looks a lot like a VESPA but not nearly as powerful. The going price for that was like 50,000 baht. So yes, electric designs are a almost twice as much as normal motorcycles despite being less powerful.

Well the underlying fact is experts give fossil fuels less than 30 years. Obviously Mother Nature is always full of surprises, so I wouldn't be surprised if the supply was less than that before she caved...

In other words, it won't matter how powerful a gas powered engine is when there ain't no more gas to power it...

Steven

[greenwanderer108]

tywais,

yes please do email me with the details about the schematic for this circuit you designed. So this brake switch, you mention simply breaks the circuit? Did you incorporate a lockable key switch to activate the control circuit?

If anything, I want to know as much about PWM circuits as possible as my basic knowledge is quite limited. Ultimately, I want to convert a 25 foot river transport boat's deisel system to be electrical using the original drive/steering system. Obviously, this is a more advanced project, so the bicycle conversion will be my crash course into electrical drive/control systems, as it's basic enough.

So, what about this magnetic sensor type throttle? Yea, the potientiometer probably wouldn't exactly be practicle for a bikes' control speed, but I'm afraid I understand next to nothing how a magnetic sensor throttle works. Will have to do some more education/research soon. In the meantime, how about that schematic?

BTW, what University do you study (or teach)? Tell us more about your project, sounds interesting!!

The OTher Mac,

About the design, as far as putting it on the back wheel, it only seemed practicle for a beginner jerry-rig design, as there is the frame extension which serves as a back seat (which ofcourse with a chain-gaurd will still serve as a seat for light riders), otherwise, by adding the components on the frame somewhere, I'd have to weld some extra brace  for the battery pack. These commercial designs use a special japan/china imported motor specefic for e-bikes that mounts right on the back wheel with no need for a chain and gear. I wouldn't even know where to acquire such a motor. However, just standard 24 volt 250-300-500 watt motors are abundant and easy to find all around Bangkok.

Anyhow, I figure, the motor and battery weight will be roughly 20 kgms max and that's not too much to hall around on the back when my battery was low/dead. Less than half of what I'm used to halling around my girlfriend. Though I imagine with her weight on top of this will be another story, thus the frame/compartment will have to be sturdy, which I'll probably consider spokless wheels later on.

80 kph??? Really, which maker? I didn't survey all the costs but  EVThais motorbikes seemed pretty efficient. Though I think the Lynux was there best one which was rated like 50 kph max speed, looks a lot like a VESPA but not nearly as powerful. The going price for that was like 50,000 baht. So yes, electric designs are a almost twice as much as normal motorcycles despite being less powerful.

Well the underlying fact is experts give fossil fuels less than 30 years. Obviously Mother Nature is always full of surprises, so I wouldn't be surprised if the supply was less than that before she caved...

In other words, it won't matter how powerful a gas powered engine is when there ain't no more gas to power it...

Steven

<{POST_SNAPBACK}>

I see what you were talking about. No, I think they meant the range was 80 km between charges. Not the max speed. This particular tuk tuk's max speed is only 25 kph, which even many e-bikes can top that speed. (Japanese ebikes can get speeds past 40 kph so I've read)

So, in this sense, such a tuk tuk is not practical, unless for short rides. Ofcourse, if it was sitting in rush hour certain parts of the city, it wouldn't be able to go faster than 10 kph anyway.

About the e-bikes, well, no I haven't seen any local designs where it charges on free pedal, though I don't imagine it would be too complex to add a small generator/mechanical system onto the circuit to top off the charge while you free pedaled. These ebikes are just basic propulsion-- with the option to pedal the weight with the motor off, or drive the weight with the motor/controller/throttle.

Too be practicle for someone living in apartment/condo, the battery pack would need to be detachable as it would be inconvenient to hull the entire 35-40 kg bike to a room/office. EVThai's wello design accomodates this for the bicycle but not for their scooters. And I havn't seen the Ecodesign prototype in real life, so I'm not sure.

[The_Other_Mac]

I see what you were talking about. No, I think they meant the range was 80 km between charges. Not the max speed.

<{POST_SNAPBACK}>

Yep, that's quite definitely... exactly what I said

50k baht for a scooter sounds rather reasonable actually, especially considering they're not coming off Japanese production lines. The problem is the credibility. Last I heard, standard scooters are considered absurd at home, but obviously that's not the case here. Never mind the drag-racing dek naew, the Bangkok family of 4 might be interested (at mass production prices). But would they have the power for that, I wonder?

Or slightly less ambitiously, I wonder would they make practical rental bikes at tourist resorts? They might cost more, but the blissful silence while driving through their tropical paradise ought to be an attraction. But could they get up those scenic hills?...