Monday, April 21, 2014

Third time's a charm

A couple of months I wrote my last entry to this blog, I got the batteries installed and everything was ready for the body the be reunited with the chassis. Two day´s ago everything was ready, checked and it was time for the first drive of my full electric Reliant Robin! You´ll read the full story below:

Starting where I left of in the last entry, every thing was ready for the body to be placed back on the chassis so that's what we did the next day in the garage. 

It all went very smooth and with all the help I got my three wheeler looked ready to drive that same day. The original wiring stayed in place and was connected back, everything still works fine. The seats where installed, steering wheel put back in and the break lines connected. 

When the Reliant was put back to gather it was time to start with wiring. The high voltage and small gauge wiring needed to be fitted from the back of the car on the chassis and the front on the body. I started with the wiring in the small box in front of the batteries and worked my way to the controller, dashboard and motor. It was quite a big project with room for error, but in the end we managed to get everything connected. 

Here is a photo of the small box without wiring, when it of the car some day I'll make a good photo with all the wiring.
It shows the contactor on the far left which breaks the high voltages current, I can switch it on and off with the key on the dash. The shunt is connected on the bottom with the 400 amp fuse. The BMS is placed above and will be powered by the two 12v 9ah batteries on the right. The fuse box in the middel will work as a easy disconnect for all the wiring and of course for safety. (ps. the photo is upside down)

When the wiring was done we tested the car for the first time but a small glass fuse broke and I did not have a new one so that was it for the day. The week after I towed the car back home where I will finish the car. With a new fuse installed we tried again, I turned the key and we heard a loud bang. The 400amp main fuse.... It turned out I wasn't to concentrated when I installed the high voltage cables. So second try no luck. It was only the fuse that broke, the controller and all other parts where not damaged. 

New fuse, again, and it was the third try to start the car. Every double checked, two weeks further and with some nerves I turned the key again. A click, the contractor, it worked. I switched the red main switch, we got power on the controller! Now it was time to connect the throttle. After some trail and error we got it going and turned everything back on. No weird noises so I put the car in neutral and touched the throttle paddle. A mechanical wine from the gearbox was music to our ears. I put it in gear and this was the result:

It works, third time's a charm! I build my own electric car with awesome help from the people around me, especially Ben :) Such a great feeling and ev grin from ear to ear!
The reverse gear jumped out of gear when I tried to accelerate backwards. 

I drove it around the block a couple of times and it drives perfectly. It accelerate very smoothly and it's fast! The screen from the BMS gives great info on voltage and current. When I floor it everything starts to go red so it has it limited but for now it's working and it's perfect! We measured 75km/h with a GPS and that was not on full throttle so it will be fast enough for me. 

Here are some photo's of the dash, the motor compartment and the batteries in the trunk:

It will need some paint, the charger need to be installed and I will need to buy a DC/DC converter. I charge my aux batteries with a solar panel now, works well but it's not a long term solution until I can place them on the roof.
The certification is the obvious next big problem. There are a couple of solutions which I will study the next couple of months. 

For now it's done, it works and I'm very very happy with the result. More data and driving stories soon.   

Saturday, January 4, 2014


At the start of November I drove to Germany and picked up the batteries at Rimo, the dealer from Elite Power Solutions in Europe. 24 Li-ion GBS cells to make a 72v 100ah pack. The cells came in sets of four that make a 12 volt pack with purple caps for protection. Below a photo of on set of four and a cut-away of one battery. 

Cutaway of one cell

The pack came with a Battery Management System that included 24 chips for each cell, a LCD screen, a shunt for measuring amps and a 'computer'. Photo of the battery pack without and with the chips.

After testing the batteries and checking that everything works we started building the case for the batteries and mounting them in the chassis. Starting with a sheet of plate steel and ending up with a welded box in the chassis. I rust proved the box used old seat belts to make sure that the batteries can't move. The big hole in the last photo is in the trunk of the car for access to the batteries after the body gets put back on the chassis. I'll make a plexiglas lid to seal it off.

I made the smaller box (left bottom photo) for all the electronics needed near the batteries. It needs some wiring and installment of a couple last instruments but is almost done. More on that later.
For now everything is done and the body can be put back on the chassis. That's the job for next week and then its all about wiring. I also have to decide on a charger and a 72v to 12v converter for the auxiliary power.
More soon!