Recently I created the support for the DC-DC controller which is now finalised. Furthermore I did a flowtest in the actual situation through the controller and DC-DC converter and the output of the small pump was 11 ltrs/min and thus sufficient.
After that I worked on the mount for the controller. Earlier I created a prototype and the batterybox support. The last one was not good enough there was too much space in between the bar and the controller.
It only was 7 to 8 mm but I decided to cut it out again and redo it.
At the same height I installed it again keeping 2 mm of space for the controller mount.
Using a piece of 30×50 from 2 mm steel I build the final support for the firewall mount of the controller.
A similar support was made for the front side which I welded onto the batterybox support.
So the controller is in place.
Given the weight of the controller (25 kg) I am going to add some reinforcement sideways.
Roofrack
When I bought the car it had a roofrack but I sold it since I believed it would result in wind resistance that would impact the range too much.
Since I am now using Tesla batteries instead of CALB I will have a much bigger range anyway. I found a nice roofrack so it will have one in the end.
Tesla battery technology
More and more information becomes available about the lifespan of Tesla batteries. If you look at the specs of CALB batteries (LiFePO4) you can see these last at least 2000 cycles (while using a state of charge (SoC) bandwidth of 10% to 90%).
On the other hand if you look at the specs of a Panasonic NCR 18650B cel which is said to be more or less comparable with the cells Tesla used you can see those only last 500 cycles.
However, this is comparing appels with pears. The 500 is while using a SoC bandwidth from 0% to 100% and it is in the last 10% where the it is most harsh for the cells. I you use the bandwidth from 10% to 90% the life cycle increases significantly according to the research “Modeling of Lithium-Ion Battery Degradation for Cell Life Assessment“. The bandwidth from 25 to 85% which is used by many OEM EV makers gives a lifecycle of 5000 cycles until 20% degradation (=80% remaining battery capacity which is still not bad if you have a 85 kWh pack for example).
Also an overview of actual user data of Tesla drivers gives a positive impression. On average after 240.000 km still 92% of the original battery capacity is remaining. If you extrapolate this to 80% (often used as the lower limit) you reach 780.000 km. Even if it would be only 80% this still is pretty good and at 80% a Tesla will still give you a decent range.
Lithium battery innovation
Battery researcher Jeff Dahn (from Dalhousie / Tesla Motors) presented an improvement to the chemistry of the cells which causes less free oxygen to be developed and longer lifespan up until 1300 or more (compared to the current 500). In the video below around 24:30 min.
I am quite confident that my electric Volvo Amazon wagon will be able to drive many electric kilometers especially since the donor Tesla vehicle only had driven 9000 km.
