Before we get into the guts of this rather substantial and significant update let's talk instrumentation.
We didn't really want a heap of extra dials knobs and buttons in the car. Rather we wanted the instrumentation to be as stock looking as possible. For example this isn't the look we were going for!
Sure the controller spyglass and emergency disconnect is somewhat mandatory but for everything else we wanted to reuse the stock standard dials and switches.
Hence the temp gauge is now the motor controller temperature, the rev counter is the current use / regen and the fuel gauge is well the battery gauge!. That last one we're very happy with ;-)
Baby Steps and Snagging List
So from the baby step drives from the last update we wanted to embark on a number of short (exploratory) journeys to build confidence. Initial test drives were nerve wracking, made worse because we now had an otherwise silent car with lots of rattles.
The first shakeout only lasted for 5kms and only around the block. As we became more confident the trips became longer but so did the snagging list. Here's what we were left with after 50kms.
Controller overheating - the obvious place to mount the controller is at the rear of the engine compartment but as we discovered this isn't ideal for ventilation so the controller would all too often slip into limp mode
Dodgy brake sensor connection - The controller thought we were hitting the brake pedal which again put the car into limp mode.
Batteries out of balance - having being harvested from another vehicle we expected the batteries to be in balance out of the box. And they certainly seemed to be when we first installed them but after a few test drives the voltages were all over the place!
In anyone's estimation that's a pretty short list.. All in all not bad considering the transformation the car.
To fix the overheating issue, we looked at relocating the controller so it could get more airflow but that would mean the loom would need to be all redone which we really didn't want to do. So we plumped for a forced and ducted air option using flexible air intake pipe. Thankfully this resolved the issue and the controller could stay in the original position.
The brake connection simply needed to be re terminated. Frankly given the number of connections and grafts we needed to make in the this car we consider ourselves very lucky that we only had one wiring issue to remedy.
The balancing of the batteries turned out to be a real pain. The spotters amongst you will understand there are 64 individual cells making up two packs in the car. Each cell needs to be the same to avoid overcharge and over discharge events. This is a discipline in itself and I won't attempt to explain how to go about it here. But I will say this, it took nearly 4 weeks to get all the cells in balance. We will no doubt record a video on the process if there's a demand.
In addition we still had the following on our to do list.
DC DC Converter - This is the device that charges our 12v battery. Our original SurePower model was DOA. We'd heard that the QC on these devices historically hasn't been the best so we plumped for Thunderstruck model which just happens to be more powerful and easier to cable.
Power steering - the PAS unit had been installed but not commissioned mostly due to the high pressure hose not being ready but also because the unit consumed up to 50Amps at 12v so we simply couldn't run it without the DC DC converter up and running otherwise our 12v battery would be drained within minutes of setting off!
Lower the car and generally make a bit prettier- just because ;-)
Pimp my EV
The Audi certainly needed some cosmetic attention both on the outside and inside. Externally we looked at new wheels and managed to pickup some snazzy S3 17" rims which certainly look the part.
We also weren't happy with the ride height so plumped for some lowering springs from Vogtland. Finally we were able to pick up some S3 mirrors to match the wheels so that completed the overall look. Internal cosmetics will need to wait until next time.
Final result.. doesn't she look purdy!
After boxing up the car and running some further tests we finally had the confidence to take the car away from the workshop to get the wheels aligned. But of course we needed to hand the keys to an unknown. We gave simple instructions (select 2nd gear, don't use the clutch etc) and, with no more info than that, the wheel alignment guy took control of the car for a test drive. the results? No dramas, first end user test went just fine.. ;-)
First charging session of the Audi, with a Cylon32 no less!
How far will it go on a charge?
Q: How do you work out the range of your newly built EV?
A: Drive it on a small circular route until it runs out of charge.
Simple solution but nerve wracking all the same. We've actually done this three times now. We purposely coded the car to not stop dead but limit the current (drop into turtle mode) so we're at least able to get to a safe place should the batteries run low. Fortunately on every occasion the car ran out of charge close to or directly in front of the workshop! The EV gods must really be in favour of us!
And the answer is 60-70km or around 170wh or 1.3Ah per km. This means that once we add the last pack we'll be at around the 130km mark. That may not sound all that good but it's on par or slightly more efficient than the Nissan LEAF. I suspect the efficiency may be to do with how aggressive we have the regen configured - the car can be driven almost entirely on the throttle from start to stop without touching the brakes. We can also elect to freewheel on the cars momentum which certainly works to great effect on the Mitsubishi Outlander PHEV.
The other reason for the efficiency could be the relatively light weight of the cars and its excellent and aerodynamics. At well under 1200kgs (even when fitted with the full complement of batteries) the Audi is lighter than the LEAF and most other production electric cars. Score!
But we're still not finished!
The car does have a snagging list, though much of it is fairly minor. And we still need to fit last of the batteries.
So the next update will see it back in the workshop for the final push , hopefully not for too long ;-)