Marcin Barabasz

imagination is more important than knowledge… A. Einstein


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Electric longboard

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I got this idea of making myself an electric skateboard after watching one episode of a gadget show in polish TV titled “Nowy gadżet” where presenter was enjoying electric skateboards made by Tesla Boards. His experience was great, but there was one problem – the price. At that time the cost of the board was around 4000 PLN which is around 1000 euros. After little bit of digging I have found loads of other manufacturers who sold assembled boards, and also kits allowing to convert your traditional board to an electric one. Unfortunately all of those were still beyond the limit I would be willing to spend for this gadget. After even more digging I have found few instructions how this was build by amateurs one really caught my attention link. The guys goal was to come down to around 300$ which is pretty good for me as well. Then I have decided I will try to make similar project. Actually the other project is very well documented and should be a must read for anyone willing to build their own electric long board. I got all needed components from HobbyKing for about 270$ including shipping, that did not include pulleys and belt, that I have found in one local manufacturer ebmia. The prices were very affordable. Next step was to modify pulleys and create a frame for the motor. Unfortunately I don’t have neither mill nor lathe so I had relay on outsourcing this task to someone else. Politechnika Wrocławska was my choice, also in case of welding it all together – the prices of all this was around 50$ in total. My biggest concern was of course welding, since it is aluminium, and I had no idea which type of aluminium the trucks were made of, some are not weldable at all. Finished frame with motor already mounted looks like this:

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As for battery and all electronics I had an idea of using an old HDD drawer. I thought it would be cool to be able to have a spare battery in a backpack to extend the range. I however abandoned this idea after realizing that first of all I wouldn’t probably need this extra range, second the whole rack was a bit too big. I have ended up using just a drawer.

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Putting all things together was really no more than one evening job, The next day I had to try it out so I did. The experience was just awesome. It was even better than I imagined it to be. First runs were smooth and carving without the need to kick was just great. When I first used the board I didn’t have much experience with LiPo batteries, and wasn’t really aware how important it is not to discharge them below certain limit. Unfortunately I used the board a little bit too much without knowing it and I went below that limit. Not only I had to come back home on foot (around 7km) but also I completely damaged one of the batteries (it got swollen and couldn’t be charged anymore). I had to pay my price for being hasty.  After I ordered and received a new battery I invested also in voltage meter and set the limit to 3.5V per cell. The meter starts beeping when the limit is reached and this is definitely the time to stop.

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Charging the batteries is quite convenient. I use IMAX B6 charger and a balancing port. This protects battery from overcharging any of the cells which is not very healthy for the battery pack. The charging does not take long – I usually set the current to 3A and then charging takes around an hour. Of course I had a small issue with charging as well. When I wanted to charge the board fast I set the current to 3 A, having 5A power supply. I thought I was save, but didn’t think that the power supply gives only 12V, and battery pack is 22.2 all together. This resulted of course in frying power supply. Fortunately it was cheap, now I use a server salvaged  power supply (thanks to my colegue) , that is capable of providing around 50A which is plenty to spare.

Traditionaly a movie of a board in action here

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