It’s fun to build EV-prototypes with 3D printer in the workshop!

Recently I have been struggling to get my Electric Motorcycle conversion (eCagiva) conversion ready for the summer rides. I haven’t had the time to install new batteries 😦 So that’s the main issue right now. And course all the supporting systems need to be upgraded to the new cell-count. Also now I have proper DC/DC (300 W IP67 Sevcon) and an new IP67 3.3 kW charger.

One main system needing to be upgraded is Battery Management System or “BMS” for short. It needs 5 more BMS PCB-boards since cell count rises from 17 to 22. With that, the voltage rises also from 54,4 V (17*3,2 V) to 81,4 V (22*3,7 V). The BMS works from about 2-4.3 volts so this is not a problem. But mechanical part is. Last summer I drove with exposed BMS-circuits, they were only protected with bikes original fairing. Not an optimum solution at all !

This time I decided to make an proper case for them. Bottom from 2 mm aluminum and “glass” from some clear polycarbonate plastic. It needs to be quite a bit thinner than last version since I don’t have much extra space after new batteries. I opted for PCB-mounting rails and custom 3D printed parts for mounting them.

I made a small video explaining my current prototyping process;

It is so easy to print usable items in plastic. Many times I need some small part for my EV-conversions and usually ABS-plastic is just fine as a material. So I sit down to my computer, desing the parts and just print them. The printing time usually is not a problem at all since I can make other things while the printer is printing.

I can warmly recommend getting or building an 3D printer if you are building an EV or just prototyping something. It’s not an cost issue anymore. You can build an working 3D printer for less than just basic EV motor controller – all the parts for 3D printer cost only about 400€ (~ $550).

One thing I’m waiting is similar DIY printing capability for metal, spesifically to aluminum. That would really widen the possibilities even more. The thing is, there are already commercial metal printers out there so I guess it’s only matter of time when someone needs metal printer hard enough to build it themselfs… Until then, I make my metal bends and cutting with “ordinary” tools.

I’m also in the process of building an vacuum plastic molder. The aim is to have plastic heated with heater and then use an vacuum pump to pull soft plastic sheet on top of the mold. It would be awesome to have the ability to mold very clear and quite large plastic parts.

When I’m learning something new, I tend to read everything I can from the subject in hand and study the basic issues surronding it. And as for the plastic molding and mold-making I have noticed that deep information can be found from quite unusual places. One great book is made actually for builders of Theater Props! The book is called “The Prop Builder’s Molding & Casting Handbook” and it’s written by Thurston James. It’s a great book and many techniques explained can be directly used in building all kind of prototypes. There is an short description for vacuum molding machine and I’m using these plans as my general instructions when building the vacuum forming machine.

Here are few pictures when we were building the heater for the vacuum molder. My son is 5 years and daughter is 2 years in the picture. They are very eager to help in the workshop and it’s actually fun to build things with them 🙂

Building Vacuum Plastic Molder heater
Vacuum Plastic molder resistor

So when ever I can, I tend to read every bit of information about the subject in hand and buy the books to my workshop bookshelf. I’ll be glad that I bought them when I need just that one last piece of information / inspiration (and the workshop network is once again down)… I warmly recommend this to anyone trying to learn something new 🙂

This is once again very exciting time for me – it’s so easy these days look for a good book and just order it from (or from other web- bookshops). After few days, I can read it and have all that precious information  permanently stored on my bookshelf. And hopefully, eventually in my own head too – but that will certainly take a much longer time 🙂

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