by **ffirman** » Thu Oct 31, 2019 8:37 am

I don't think the economics of the use once battery adds up, and here's why.

To make a LIon battery - Tesla is doing around $120/KwH (US), and for the model 3 SR with a 50KwH battery that comes to $6000 + packaging, so lets say $10k US ($15K NZ) for a battery.

From the current drops in capacity from other Tesla batteries, it should be able to do 1500-3000 full cycles before it has lost 20% of it's original capacity. So that gives a total distance drivable (1500 cycles at 350km/cycle) of 525,000km.

And if 50Kwh with a 90% charge efficiency of power is used to change the battery each time (55KwH), at 25c/Kwh = $13.75 per charge in power cost.

So the total cost of the battery for the 525,000km = $15,000 + 1500*$13.75 = $35,625.

Now the Al Air battery is said to be able to do 1500 miles / battery or 2400km. To it to be able to compete just on price, then the new battery would have to cost less than $162. That is the $35k/500,000km*2400km.

I am not sure that can make a Al Air battery for $0.47/kWh. I'm not even sure the electricity to make the Aluminium can be done at 47c/kWh or stored energy in Aluminium.

Now as for the charging time.

We now have a Tesla SR+ with the 50kWh battery and an approx range of 350km on a full charge. We charged to 100% and drove to Whakatane from Auckland. The car said we would arrive with 14% left in the battery. When we got to the Mount, after 3 hours of driving I and the kids needed a stretch, so we went to the Mall and put the car on charge. The car was on 37% at the time. We had a loo break, some lunch and after 30 mins of that, returned to the car and it was at 77%. Drove to Whakatane and arrived on 54%, which means we would have arrived on 13% if we hadn't stopped.

The outcome from this is that the battery capacity of the smallest Tesla is still larger than what I personally can deal with, and having a 20-30 min break for a stretch etc, is welcomed. So in this case the driving distance and the time to charge are a zero issue, so the Al Air battery would provide no extra benefit over the existing battery tech we are currently already using.

Fran.