Building an EV in 1 week – Day 3

Well after a very long day at 11pm last night we went for the first drive in Michael’s new EV! Just three days after starting the conversion.

We spent most of yesterday wiring – for example I spent some time working out how to connect all the vacuum pump tubes, and some machining was required to get the different size tubes to mate. We also installed the under car cables, and various Paktrkr cables and sensing leads. Andrew did a great job wiring up all the 12V and 96V switches and relays. The controller plate that came with the Chinese kit made a nice base for the wiring.

In the morning we cleaned up and painted the front rack, installing it just after lunch. The metal work looks really nice, the pressure pack black paint makes a very nice finish. The people I worked with (especially John) are much better at the detail work than me, so the overall finish is much better than my first EV.

We had lots of help from many people and visitors over the day. At one stage we had one group installing under car cables, another filling the transmission with oil, another working inside on instrumentation.

In the early evening we were so close that we had to push on. Slowly we wired up the final connections under the bonnet. We brought the electrics up in stages; first we tested the the 12V side – making sure the relays switched when the car key switch was turned to ON. Then we connected the 96V supply and tested the brake pump and DC-DC converter. A little adjustment of the vacuum switch and the brakes were working well – you can feel the power assist on the brake pedal. Then the DC-DC converter was tested by connecting it to the car 12V system. It worked well, around 13.8V with only a little sag even with high beams on.

Finally we connected the last engine cable and tried the motor. Off it went – spinning happily and turning the wheels in the correct direction up on the stands! Great – we were very happy! Even though it was raining heavily we couldn’t help ourselves – it had to be driven! So we took it for a spin around the block. It drives very nicely, the heavy duty suspension Michael had installed made for a nice ride despite the increase in weight. It was very quiet and we could changes gears from 2nd to 3rd just fine without the clutch. A very satisfying first drive.

A few problems still to work through – there is a transmission oil leak and the acceleration of the car seems low (e.g. less than 100A peak current), I suspect due to a throttle pot or connection issue. We are having a break today, but will look into these problems Monday. There will also be some clean up and adjustment work over the next few weeks before heading for official inspection.

We have some YouTube video of Day 3 of the EV conversion taken by an OLPC rigged up by Joel above the car (the video is actually labeled Day 4). You can see the background light level fading in and out as the rain storms came and went over the day. Towards the end we re-mounted the bonnet, then you can see the car disappear and re-appear as it goes for it’s first drive!

Overall an amazing project which has gone forward much faster than expected.


Building an EV in 1 week – Day 1
Building an EV in 1 week – Day 2
David’s EV Page

15 thoughts on “Building an EV in 1 week – Day 3”

  1. Really cool work! So the real question is how much did this one end up costing? Do you have thoughts for reducing the cost for this type of conversion?

  2. This EV conversion came in at about $8,000, about half of my first conversion. The next steps in halving again would be some open hardware speed controller and charger designs.

  3. Thanks Duncan. At this stage I am just thinking about the design, but pls feel free to start researching EV charger and/or controller designs. A few people (like ian @ zeva) have been working on their own controllers, and there are some EV development lists like evtech where people discuss such designs.

  4. Read your article on the one week ev with interest. Tried to look up Eugen in the yellow pages for Brisbane but to no avail. Also looked in the goombi web site but no luck. Do you have a web address for the Chinese Kit and if so what is it. Keep up the good work.

  5. Great effort but what always worries me with electric vehicles is what happens in an accident.
    With your design of having a large number of the batteries up front in the “engine” bay – I dread to think what the issues would be in a head on accident.
    You obviously got insurance – how difficult was it? Is it under a kit car basis?
    Keep up the good work you have some very interesting projects
    Cheers Francis
    Manly, NSW

    1. In the worst case all or part of the battery pack will be shorted, large currents will flow, they will overheat and catch fire. There are various fuses and inertia switches to prevent this. You won’t get an explosion, as unlike fossil fuels batteries can’t release energy that quickly.

      Looking at my car in a bad head-on I figure the battery racks would deform and the batteries would flop about but stay connected by their cables and nothing much would happen. It looks safer than a 100kg monolithic internal combustion engine block that would come through the firewall and crush me.

      Francis, do you worry about carrying 70kg of high explosive around under your rear seat in your petrol car? It’s funny what habits we become accustomed to.

      Re insurance I just obtained third party property ($140), if the car gets badly damaged in an accident I’ll just buy another $1,500 Charade.



  6. I really like to read this kind of projects. Busy collecting info about the gov rules here in Holland.
    Still coming closer to the moment to actually go for it.

    Please, Can you give us the Chinese kit goombi site or make Eugen’s site link public?

  7. Dear David,
    Looks fantastic! Amazing that you guys did it in such a short time! Many hands do make light work…
    I’m writing from Malaysia and personally very keen to learn how to do a proper conversion as well as the end results. Mileage between charges, proper wiring methods, Battery Mgmt unit etc etc.
    Will you be doing any conversions in early 2011? I’d love to come by and assist and learn too.

  8. David
    Thanks for the great input. I’m reading and learning everything I can and am presently converting a ’87 Nissan D21 2wd PU with a defunct Z24 engine. I am in the process of stripping the vehicle. Since I am disabled with MS, this needs to be a very low budget process, so I am very interested in your cost saving perspectives regarding motors, controllers, batteries and chargers. Although I have lots of mechanical experience, I’m pretty weak at electrical.
    Dave Dixon
    713 Horseback CT NE
    Salem, OR. 97301

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