The motor is in!

I got the left transmission mount today and fabricated a motor mount in 40x40x4mm angle steel. I'm not 100% sure about the geometries since I used the bottom transmission mount from the gasoline transmission. It doesn't fit the diesel transmission that good but at least it holds everything about right. I have ordered a used diesel bottom transmission mount so when I get that I will adjust the motor mount a well.

Installing the motor and transmission using the hoist

The motor is in!

When I decided on the Kostov K9HV motor I really took a chance when it comes to its size. I see now that it is a perfect fit! There is only half a centimeter between the front side of the motor mount and the frame of the car. The back side of the motor mount I actually had to reduce by a centimeter to get it in there. The rear axle of the motor is protruding under the frame. So a larger motor would not fit. At least not a longer motor.

A tight fit between the motor mount and the car frame

Integration test no 3 - succeeded!

I made two integration tests today and tried to mount the motor to the transmission.
After my frind Ola had machined off a centimeter of material from the flywheel it was balanced enough to test. I have been thinking of getting a special tool for centering the clutch plate to the flywheel bu now I just used a vernier caliper to measure the distance between the clutch plate and the holes in the flywheel and centering it manually. That turned out to be good enough. The garage hoist was a bless to use for navigating the 55 kg heavy motor/adapter/flywheel/clutch assembly.

Mounting the motor to the transmission

 

It turned out that the fit is so tight I could not get the motor and transmisstion together. Maybe the flywheel for the VW New Beetle, for which the adapter is originally made, has a smaller flywheel.
So, test number two failed as well.
I then removed the gear ring on the flywheel to make it smaller and shaved off a small indent on the inside of the transmission that seemed to be in the way.

After removing the gear ring from the flywheel

I used a simple propane burner that I normally use for an (other) outdoor stove to heat the gear ring and then a hammer and chisel to beat it off.

The indent before and after shaving with a angle grinder

Without the gear ring and indent I managed to push the motor and transmission together! Horray!
After reading several electric conversion blogs I now know that if you convert at car to electric you have to make a video with the first test run of the motor and transmission together ;) So, here is mine:

First integration test - failed

Since the flywheel that matches my diesel transmission is unbalanced I tested the flywheel and clutch from the gas engine. The flywheel fits the adaptor allright, but the clutch is too small. The center hole formed by the clutch fingers is too narrow for the release bearing and the oil seal in the transmission. So its back to trying to balance the diesel flywheel. I think it can be machined into balance with a milling machine. I just have to find someone who has one...

The gas clutch

The diesel clutch

After I split the engine and transmission I had a chance to compare the original gasoline transmission with the diesel trans that I plan to use. I realized then that they use different drive shafts. So I have to get new drive shafts that fits the new transmission. So much for praising the VAG component system. :(

The drive shaft flange on the gas transmission

And the same on the diesel transmission

I could also make certain that the gas transmission does not fit the adapter plate. It was tempting for a while to use the existing transmission, but now it just to bite the bullet and get the diesel trans to work.

The adapter does not fit the gas transmission

A good thing is that I have now discharged all 68 lithium cells. I'll let them rest during the weekend and see on monday is they need further balancing.

A small step for man, but a huge leap for mankind

The A2 is now officially deiced. That is the ICE (Internal Combustion Engine) has been removed together with the exhaust.

I bought a garage hoist that did the job beutifully. I first had a plan to just let the engine down on a small garage trolley but I realise now that it would never have worked. The hoist cost about the same as two lithium cells ;) Maybe I can sell it later on.

The only thing left on the car now that has to do with gas propulsion is the gas tank which I will remove tomorrow.

Tear down the car!

Yesterday I finally gathered enough courage to start the disassembly of the A2. I have been driving around in it for almost nine months now and I really start to like it. I guess I'll have to do the conversion really fast!
I am starting with the front of the car so I can work on the engine and transmission from the front instead of from underneath. Also I will remove the radiator and some more unnecessary stuff in the front.

The front without the bumber cover (I do use jack stands BTW)

One interesting finding was that the condenser for the AC is located just in front of the radiator (and actually looks the same). My plan right now is to keep the AC circuit intact and maybe get it to work later. I don't want to remove any AC hoses since that would cause refrigerant to leak out and that's not good for my own health nor the environment! So, I will just have to be very careful and also find a place to stuff the condenser while building.

The (really dirty) condenser and the radiator behind

Before I started this I knew there are a lot of cables, hoses and wires attached to a car engine, but I didn't know there are a billion! After a full day of detaching stuff more or less access friendly I have managed to get through 11 of the 22 pages of instructions for removing the engine. And all of that is removing stuff attached to the engine.Well, not all of it. It did remove the bumber as well and some other things like wheel linings to get better access to the wires and stuff.
This is was the poor A2 looks like now.

The poor A2

As a sort of compensation to all that I got a friend today. Our dog Jenny decided to join me and supervise the battery balancing.

Balancing OK!

Motor arrived

The Kostov K9HV arrived yesterday from Bulgaria. It is a really neat little motor and I am amazed it will be able to accelerate the A2 0-100 in 10 seconds and give it a top speed of 130 km/h. Well, we'll see!

First spin

I connected it to 12V and gave it a first spin and it works allright. I also connected the motor-transmission adapter to it.

When I mounted the flywheel to the adapter I noticed a substantial unbalance. So severe that I had to shut it down after just a few seconds. After some investigation it turns out the flywheel is unbalanced!

The unbalanced flywheel. Note the big piece of material missing in the lower left!

I thought I was smart to get exactly the flywheel that is used on the engine that fits the transmission that I'm using. But that engine is a three cynlinder diesel engine which, because it has only three cylinders, is unbalanced. To counteract the imbalance of the engine VAG made the flywheel equally unbalanced the other way. That means the flywheel will only work with those three cylinder engines and not my perfectly balanced little Kostov motor :(
So the solution is to use another flywheel. I hope the existing flywheel from the four cylinder petrol engine in the car will work. The only difference I know of is that the clutch is smaller on the petrol engine so maybe the diesel clutch will not fit.

Battery balancing has started

Today I started the battery balancing procedure. In order to keep all the lithium cells at the same charge level, so that no single cell is overcharged during charging or over-discharged during driving, they have to be belanced. That is be at the same level of charge. After they are balanced I can charge the whole pack together.

The balancing procedure I use is called bottom balancing. This means that the cells are given the same charge level by discharging them to the same resting voltage close to empty. To do this I put together a "bottom balancing aparatus" consisting of a Powerlab 8 battery workstation, a 12V lead acid battery, a 12V heater fan, and a PC with a control software.

The "bottom balancing apparatus"

The Powerlab 8 discharges each cell to a voltage of 2,75V using a constant current/constant voltage schema. This means that it starts discharging each cell at a constant 40A until the cell reaches a voltage of 2,75V. If I would just stop discharging at that point the cell would recover and the voltage would quickly rise. Therefore the Powerlab successivley lowers the current to withhold the 2,75V and it does so until the current has dropped to about 4A and then the procedure stops. At this point the cell voltage starts to rise but not so much it would have done if I would have only used the 40A discharge rate. When I measured one cell about 10 hours after discharge the voltage hade risen from 2,75V to 2,97V. I guess that when I have done all the cells I might have to make another round with a lower current, maybe starting at 4A, to get them even more balanced.

So what is the lead acid battery and electric heater fan for? Well, when discharging a cell the energy has to go somewhere. So the Powerlab, while discharging a lithium cell, charges the lead battery, which is also the power source for the Powerlab. And the lead battery will eventually become fully charged. So the heater fan discharges the lead battery. In effect, the energy from the lithium cells are transformed into heat that warms up my garage! So far I have a manual switch  on the fan and I turn it on when the battery gets close to full and off when it gets close to empty. An automatic thing for this would be nice!

The PC software tracks the discharge procedure and makes pretty graphs.

The discharge of the first cell which was first charged to 3,5V

The very first cell I charged to 3,5V before discharging to see what capacity it had. My first idea was to do that with all cells, but it just takes forever! The charging took about 2 hours and then the discharge another 2,5 hours. So after that I only discharge the cells. This takes about 1 hour 20 minutes per cell so balancing all 68 cells will take a couple of days!

I charged the first cell to 3,5V which is not fully charged. And then I discharged it to 2,75V, which is not fully discharged (2,5V is supposed to be fully discharged). And I manged to discharge 109 Ah out of the cell which is almost 10% more than its nominal capacity of 100Ah. Looks good! I hope all the other cells are as good. I will make sure no cell has a substantially lower capacity than the others by frequently measuring all cells voltages during the first charge of the whole pack.