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    Prototype EV for race

    I'm guessing the reason you would need to increase battery mass to change voltage is because your cells are huge and you only have 1 in parallel. @liveforphysics. Higher voltages nearly always means better efficiency and better power density. But to actually capitalise on this you need to have...
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    2011 Zero XU - Battery replacement options?

    Wise to steer clear of RC stuff then if it's a serious build. In my opinion 18650's are the best choice when buying new if you don't mind the complexity of construction. You're right that you need to choose the right cells but LG,Pano,Sony and Samsung all do a decent automotive spec that is up...
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    2011 Zero XU - Battery replacement options?

    Hello, Lots of options. Depends how good you want it and how much you want to spend. Take a look at my thread: https://endless-sphere.com/forums/viewtopic.php?f=10&t=85758 This is a 14s 55ah pack..... It would fit inside an xu case with room to spare. It would be about the best you could...
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    Prototype EV for race

    Hello, welcome to the forum. What interesting machine! What is the race? Is there a reason you're limited to 24v? The easiest thing to do might be to increase voltage and change the gear ratio? I'm sure if your motor is rated at 24v it'd be ok at 36 or even 48.....
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    Hub drive vs Chain drive

    As a plus point for hub motors you have none of this to worry about!
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    Hub drive vs Chain drive

    Just to add my 10p in, hub motors aren't just heavier, they are also unsprung mass, affecting the ride and handling. With a separate motor you have more flexibility over you rear axle design, but by far the biggest advantage is what John says, higher motor speeds equals better efficiency and...
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    Electric Motorcycle (50cc Equivalant)

    Hi BB, like macribs says It's only valid in the UK. For this to be registered in another country it would have to pass the local tests. Which for most EU countries shouldn't be too difficult. I am looking into homologation for within the EU, but this is likely to be just something I...
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    Electric Motorcycle (50cc Equivalant)

    Thanks UKPhil! I've not had any problems getting the bikes through an MSVA as all the parts exist. What I have been developing is a way to keep it premium and light so I've made some special things which I'll share on here shortly. More and more things are available, since I got my first...
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    BobCs emax scooter thread

    this is really great work. I also can't remember the last time I heard the word 'gurt' and it really made me smile!
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    Electric Motorcycle (50cc Equivalant)

    I've been reading your arduino cell balancing thread, I'm not going to comment on it yet because I've got about 6 months more to read but I'm looking forward to finding out how you got on! Because your using relays can you active cell balance? Or are you still using the top down approach?
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    50cc equivalent motor setup help.

    Hi there, this switch cannot replace a contactor I'm afraid. A contactor is designed to switch in a controlled environment so that the sparks are unable to oxidise. A contactor will also be controlled by your BMS so that it can safety disconnect your battery in whatever conditions you deem...
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    Electric Motorcycle (50cc Equivalant)

    Hi bobc, thanks for the comments! I am intrigued at what gizmos you're tinkering with!
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    Electric Motorcycle (50cc Equivalant)

    Ah ha, good spot! I didn't even know this was still there! Yes, this was a while ago, first bike I got road legal to prove the concept. I used turnigy batteries at the time but decided to build by own packs as there was nothing, and there is still nothing available off the shelf that's good...
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    Electric Motorcycle (50cc Equivalant)

    hi there. This bike doesn't classify as a self build. Because I have a company, this bike counts as a new vehicle. In the U.K. you can do a single vehicle type approval and then you're ready to roll. It has a number plate with current reg etc. I use a company called lexham insurance. They are a...
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    Electric Motorcycle (50cc Equivalant)

    thanks Jim! Great to hear some feedback. I have a few shots of the build in progress that I'll post soon. I do plan to make a small number of bikes to sell soon but in the U.K. only. I may also sell frames on their own if people are interested.
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    Electric Motorcycle (50cc Equivalant)

    Looks good, nice work.
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    Electric Motorcycle (50cc Equivalant)

    Thanks! You should start your own thread! I would like to see your frame and battery! Whats the battery going to be size wise? have you thought about spot welding with nickle steel tabs? It's by far the easiest route in my opinion. I do like spinning magnets solution though I have to say!
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    Electric Motorcycle (50cc Equivalant)

    Thanks for the comments! I am planning to post some videos of it in operation soon!
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    Electric Motorcycle (50cc Equivalant)

    Thanks! I use a 140t sprocket on the wheel and 12t on the motor. It's 11.6:1 It's #219 chain used on go carts. I got these custom sprockets from rocket sprockets. The motor does about 6000rpm. The bike is mechanically restricted to around 37mph with those sprockets, I took one bike to 60mph...
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    Electric Motorcycle (50cc Equivalant)

    We're seeing at least 5ah already on 21700 so you're right, it's only a matter of time before they supersede 18650. They are slightly less space efficient than 18650's which is worth baring in mind. At work we've tried to calculate what the optimum size is for a cylindrical cell. Have you ever...
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    Electric Motorcycle (50cc Equivalant)

    Thanks for the tip!
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    Electric Motorcycle (50cc Equivalant)

    Thanks, converting your insight to lithium would be a good project! I'm in the midlands near Coventry. We use pulsed arc welding on the tabs rather than resistance welding which is how most spot welders work. This is much better for dissimilar metals.
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    Electric Motorcycle (50cc Equivalant)

    Hi, thanks for the comments. I've started to look at 21700's. LG are also going to make them, they won't be exclusive to Tesla and Panasonic. However there aren't any significant energy density increases yet, by our measure the biggest driver for moving to 21700 is cost, which is why it'll...
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    Electric Motorcycle (50cc Equivalant)

    I thought 'Aussie rules' (sorry!) about mopeds were pretty similar to Europe? Stealth electric bikes have been doing this game for a while in Oz but I've always wondered why they never made them road legal?
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    Electric Motorcycle (50cc Equivalant)

    Hi, I am in the UK yes. Thanks for your comments. I actually work for an automotive OEM and also do a bit of design consultancy on the side. I need to do some more testing on these parts, and after that the plan is to buy some injection moulding tools to get the piece cost down. I will make...
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