Electric Vehicle Conversion Part Two.

In Part Zero and Part One, I took the long way around on an EV conversion project by purchasing this crashed Hyundai Kona Electric for parts:

Disclaimer

This post series is an incomplete informational account and does not constitute any kind of training or "how to" on any process. Working safely on cars in general, and EVs in particular, requires knowledge and skills which are not covered at all in these posts!

Disassembly

After recording CAN logs of the complete car, it was time to dismantle it. A bunch of mates came and helped for these jobs, which was fantastic (thank you everyone!)

First we verified the high voltage system was correctly de-energised and interlocked out, drained the coolant and gear oil, pulled out the drive shafts, and took off the remnants of the front of the car:

Then we could lift out the "motor stack" (motor + inverter/VCU + charger + pumps + AC compressor):

The front of the Kona looks pretty empty now:

Battery Pack Out

A few weeks later we were able to remove the battery pack. Like most OEM EVs, the battery pack bolts flat under the car.

After re-verifying the high volage was safe and removing the remaining cables, we had to flush out the last of the coolant from the battery pack's cooling system. A Hyundai Technical Service Bulletin (PDF) published in the US¹ gives an overview of this process. There is also an unofficial and informational YouTube video by "HyundaiTech" showing them following the process.

In the YouTube video at 12:56 they show the custom Hyundai flushing tool and mention that if you don't have it then you can use compressed air "not exceeding [...] 2 bar". Flushing from a compressor seemed to work fine, we started with minimum air flow and worked up to 2 bar:

(We left some of the other coolant hoses and a valve attached while doing this flush, as shown in the picture. This isn't the official process, but without a hoist it was a lot more convenient and coolant was blown out of these parts as well. Hopefully nothing was damaged.)

Then it was time for the battery pack to finally drop out. The official process for this is pretty easy: raise the car on the hoist, put a fancy scissor table under the pack, loosen the mounting bolts, and lower the pack down using the table. 🎉

(Still from HyundaiTech's video 11:44)

If you don't have the scissor table, with a hoist you could probably lift the car off a table or dolly that's holding the battery.

Uh... what if you don't even have a hoist? 🤔

When removing the pack from the Outlander, I was able to approximate the process using jacks: I slid moving dollies under the pack, put some cardboard on top to pad them, lowered the car very carefully until the battery pack was touching the dollies, loosened the mounting bolts, and then lifted the car back back up on the jacks until the dollies could roll out.

However a Kona battery pack has almost six times more capacity so it's a lot taller than an Outlander battery pack! Under the Kona rear seats there is a "bump" in the pack, this is the tallest point and the pack is a little over 30cm tall there². If you peek under the rear of the car, it looks like this:

It was going to be a challenge to safely lift the car high enough using only floor jacks.

In the end we managed it, by working very low to the ground. First we took out most of the battery pack mounting bolts, there are some in the middle of the pack as well as around the edge. Now the pack was only held in by four bolts on each side.

Oli had picked up some 50mm diameter steel pipes to use as rollers:

We very carefully lowered the whole car using jacks (front and rear) until the pack was almost resting on the rollers, with a sheet of MDF as a pad in between. This put the car very close to the ground! Then we finished unbolting the pack (we still had just enough room to get a ratchet onto the mounting bolts). We slowly lifted the car back up on the jacks, leaving the battery pack down on the rollers. Then popped jack stands under it to secure.

This made it possible to carefully roll the battery pack out:

I wouldn't recommend this process, but it did work this time: nothing was dropped or suffered undue force, and although the car seemed to be perched precariously at times there was always a fail-safe support in place to stop it dropping on the pack or a person. Naturally no one needed to work under the car at any time while it was suspended, either!

Please comment if you've used a better method to remove an EV battery pack in a home garage.

Stripping the interior

This has taken longer than expected. Trying to preserve the Kona interior while dismantling it has been tricky, especially without the official documentation. Sometimes there's a part that turns out not to clip in:

Oops!

However, with some patience it's gradually coming out:

As well as needing to get the car shell out of my shed, this means I can recover the remaining parts that might be useful in a conversion. This includes the gear selector units (which has its own computer), and the smart key module:

The last part I need is the remaining wiring loom behind the dash pad.

What next?

I need to get some of these parts talking to each other on the bench, and do a very deep dive into decoding all the CAN logs! Both may take a little while...

There is also a thread about this on openinverter, where I mean to post more frequent updates about this project as well. Feel free to jump on there if you're keen!

Next update coming soon, I hope.