pawelr98
1 µW
Hello
I'm new to the forum so I wanted to start with showing my e-bike that I use for daily commute.
Let's start with the specs:
Steel Frame 24" bike from ~2007
MY1016Z 250W 36V brushed DC motor
"Because" freewheel aluminium crank
2x28T schimano gears on crank
11S6P LG MG1(10A 2900mAh) battery- self made
PWM driver based on TL494 and mosfets-self made
Speed:20-25km/h normally, 30-32km/h on flat road with lowest gear ratio and fully charged battery
It all started in early 2016 when I got the idea.
I was in my last year of highschool.
It was at that time when I decided to actually build an ebike.
Later I purchased a stick welder and welded the frame extension(frame of a small children bike was cut into pieces).
Then I could really start using it.
At that point I was using 3x12V 20Ah lead-acid batteries and I didn't have freewheel crank.
Pretty much how it looked like back then.
[youtube] https://www.youtube.com/watch?v=TKPS6F4EImU [/youtube]
I was riding it from time to time to get some parts from hardware store.
Because I had a normal crank I had to ride with legs up.
The shadow casted by the frame and myself looked a bit similar to a person "riding" a broom.
This is where the name comes from.
But most likely you noticed the welded extra pair of pedals.
At the beggining it served two purposes:
-place for legs when riding
-motor activation
The "motor activation" part is because of Polish bicycle law (most EU countries have similar laws).
E-bike can be called a standard bike when following conditions are met:
-250W max nominal motor power -check ("nominal" giving a lot of room for extra power)
-48V max voltage -check
-25km/h max speed -check (mechanical limit based on gear ratio)
-Motor activated by pressure on pedals- check
They really did directly state that there must be "pressure on pedals".
So I did exactly that. There's a simple thyristor circuit which activates the controller when pedals get pushed once.
Later I purchased a freewheel crank which finally allowed me to ride normally.
The worst thing that remained were the lead-acid batteries.
They were just darn heavy. ~20Kg on the frame extension (high center of gravity) made it rather unstable on corners.
I didn't use it much because I was spending my time in a different city attending university.
The great breakthrough came when I decided to put together a spot-welder for 18650 cells.
I purchased cheap new LG MG1 cells which had been removed from new batteries.
They measured like a brand new cell.
Battery ended up like this. Balance ports divided it into 6S + 5S for charging with Imax B6.
I don't use any BMS system. Just balance charger.
I monitor the voltage using small voltmeter and the battery is protected from shorts by a 25A fast-blow fuse.
After I made the battery I decided to do some more work on the bike.
Removed some junk parts I welded years ago, aligned the rear wheel, replaced the front brake(only one), added lighting and many other small improvements.
The state of the bicycle as it is today.
Doing commute 2 days in a week because it's faster than public transport in early hours.
Public transport can get really crowded and people can even "fight" for ability to get into a bus.
Really gets attention when I roll into university gate on this thing.
Chinese throttle cracked on my first commute. Had to replace hall-sensor(leads broke off) and tape it back together.
24" wheels are small for my height (181cm) so I just happened to hit the key when getting off the bike.
The throttle went into pieces. Really low quality plastic.
Running fixed gear, at one point I melted the line during welding
.
Simple protection, a steel rod frame along with a chain and a padlock.
Steel frame is easy to weld using cheap stick welder. Aluminium is not.
If I am to replace the frame then I'm going to get another steel frame.
250W is NOT ENOUGH for rides in "hilly" terrain.
You can kill the motor faster than you think.
I increased the gear reduction to prevent the motor from burning on daily commutes.
I really wish Poland would increase the motor limit to 350W at least(500W would be ideal).
However plenty of e-bike people around here are just using stronger motors which is illegal(such ebike is classified as moped).
Not that police cares much.
Each time the motor struggles I'm considering putting a stronger brushed DC motor or a BLDC motor(a normal one I can just put in the mounting place of current one, it will have better cooling than a hub motor).
Maybe if I kill the current motor then I will really consider purchasing a new stronger one.
For now I prefer sticking to the law.
I'm new to the forum so I wanted to start with showing my e-bike that I use for daily commute.
Let's start with the specs:
Steel Frame 24" bike from ~2007
MY1016Z 250W 36V brushed DC motor
"Because" freewheel aluminium crank
2x28T schimano gears on crank
11S6P LG MG1(10A 2900mAh) battery- self made
PWM driver based on TL494 and mosfets-self made
Speed:20-25km/h normally, 30-32km/h on flat road with lowest gear ratio and fully charged battery
It all started in early 2016 when I got the idea.
I was in my last year of highschool.
It was at that time when I decided to actually build an ebike.
Later I purchased a stick welder and welded the frame extension(frame of a small children bike was cut into pieces).
Then I could really start using it.
At that point I was using 3x12V 20Ah lead-acid batteries and I didn't have freewheel crank.
Pretty much how it looked like back then.
[youtube] https://www.youtube.com/watch?v=TKPS6F4EImU [/youtube]
I was riding it from time to time to get some parts from hardware store.
Because I had a normal crank I had to ride with legs up.
The shadow casted by the frame and myself looked a bit similar to a person "riding" a broom.
This is where the name comes from.
But most likely you noticed the welded extra pair of pedals.
At the beggining it served two purposes:
-place for legs when riding
-motor activation
The "motor activation" part is because of Polish bicycle law (most EU countries have similar laws).
E-bike can be called a standard bike when following conditions are met:
-250W max nominal motor power -check ("nominal" giving a lot of room for extra power)
-48V max voltage -check
-25km/h max speed -check (mechanical limit based on gear ratio)
-Motor activated by pressure on pedals- check
They really did directly state that there must be "pressure on pedals".
So I did exactly that. There's a simple thyristor circuit which activates the controller when pedals get pushed once.
Later I purchased a freewheel crank which finally allowed me to ride normally.
The worst thing that remained were the lead-acid batteries.
They were just darn heavy. ~20Kg on the frame extension (high center of gravity) made it rather unstable on corners.
I didn't use it much because I was spending my time in a different city attending university.
The great breakthrough came when I decided to put together a spot-welder for 18650 cells.
I purchased cheap new LG MG1 cells which had been removed from new batteries.
They measured like a brand new cell.
Battery ended up like this. Balance ports divided it into 6S + 5S for charging with Imax B6.
I don't use any BMS system. Just balance charger.
I monitor the voltage using small voltmeter and the battery is protected from shorts by a 25A fast-blow fuse.
After I made the battery I decided to do some more work on the bike.
Removed some junk parts I welded years ago, aligned the rear wheel, replaced the front brake(only one), added lighting and many other small improvements.
The state of the bicycle as it is today.
Doing commute 2 days in a week because it's faster than public transport in early hours.
Public transport can get really crowded and people can even "fight" for ability to get into a bus.
Really gets attention when I roll into university gate on this thing.
Chinese throttle cracked on my first commute. Had to replace hall-sensor(leads broke off) and tape it back together.
24" wheels are small for my height (181cm) so I just happened to hit the key when getting off the bike.
The throttle went into pieces. Really low quality plastic.
Running fixed gear, at one point I melted the line during welding
.
Simple protection, a steel rod frame along with a chain and a padlock.
Steel frame is easy to weld using cheap stick welder. Aluminium is not.
If I am to replace the frame then I'm going to get another steel frame.
250W is NOT ENOUGH for rides in "hilly" terrain.
You can kill the motor faster than you think.
I increased the gear reduction to prevent the motor from burning on daily commutes.
I really wish Poland would increase the motor limit to 350W at least(500W would be ideal).
However plenty of e-bike people around here are just using stronger motors which is illegal(such ebike is classified as moped).
Not that police cares much.
Each time the motor struggles I'm considering putting a stronger brushed DC motor or a BLDC motor(a normal one I can just put in the mounting place of current one, it will have better cooling than a hub motor).
Maybe if I kill the current motor then I will really consider purchasing a new stronger one.
For now I prefer sticking to the law.
