The Longest Possible Trip In One Day — With The Shortest Possible Range

In light of the just announced 150–350 kW High Power Charge system from ABB to be presented in Stuttgart, Germany, this October, I think this story needs to be told now, before it is so outdated no one will care.

When first-movers travel far

118 km (73 miles) is what my Nissan e-NV200 Evalia showed as possible range one cold morning fully charged. In my daily commute it was actually often quite accurate. However, in this case the outdoor temperature was below 15 ⁰C, and that meant even lower range.

I had just decided to lure my family into a trip that would take very much longer than anticipated. But hey, it was fun doing all the stats!

The e-NV200 is a big van that can be configured to seat 7 people. It has recently been announced that the 2018 version will have a new 40 kWh battery. In my case though, it was equipped with the 24 kWh battery also found in the Nissan LEAF at the time. In other words: a very large and roomy EV, with a very short range, due to its weight and bad aerodynamics.

A lot of stops and a lot of luck

With 50 kW fast chargers along the highways in Denmark, I am actually not experiencing range anxiety at all. There are 2 main providers competing for charging locations in the country, Eon and Clever. This means almost all rest areas on the highways has fast chargers. Great! But there is a catch. Most charging locations only offer one point of charge, so you can easily find yourself waiting for someone else to finish charging, making it very difficult to plan your time of arrival.

Anyway, on this trip we had more than 400 km (250 miles) ahead of us, and the unexperienced EV driver might make the mistake of just dividing the total distance with the range, and thus anticipate 3 charge stops in this case. Not even close to reality!

This is how we ended up charging on this trip relative to distance and time respectively (energy consumption approx. 2.5 miles/kWh):

That’s 8 stops of more than 2 hours total charging! But why? Well, first of all, just because your EV says 118 km of range, that does not mean you will drive 118 km and then look for a charger right? Secondly, a fast charger will charge you EV to about 80% pretty fast (from 20% to 80% in roughly 15–20 minutes), but that last bit up to 100% you can forget about, because that would take you an additional 30 minutes, due to the battery management system taking extra care not to overheat the pack.

So, in order to maximize average speed, you need to optimize your charging to hit in the range of 20–80% battery charge. This actually decreases your useful range to a maximum 70 km (44 miles). Bummer.

Anyway, this trip “only” lasted 8 hours. And in the end we found that a quarter of that time we spent charging. The kids even got tired of saying “are we there yet?”, and accepted that daddy is an EV nerd. I just thought that we had been very lucky not to run into occupied or defective chargers.

Bigger batteries or faster charging?

This trip presented an interesting dilemma. Would I prefer a larger battery or faster charging? Well, of course I would like both, and I could have that if I bought a Tesla Model S. But if economics matters, and I had to choose, I would actually prefer fast charging in combination with more charging points at each stop. The uncertainty of wether there is a free plug is extremely annoying.

If we had made this trip in the 2018, 40 kWh battery version of e-NV200, we would likely have needed to charge 4 times in order to reach our destination. With 50 kW chargers that would have taken the same total of 2 hours charging time.

However, if we had access to 150 kW chargers with the 24 kWh battery, we would have had the same 8 stops, but we would only have spent 7 minutes of charging each time. Totaling 1 hour or less. Although I’m not sure a 24 kWh battery would actually be able to suck up electrons that fast — you need bigger batteries for that.

In this context, I would argue that an EV with a 50 kWh battery and access to fast charging of at least 100 kW hits the sweet spot. Wait, that’s the Tesla Model 3! Coincidence? I think not.

The barriers for wide EV adoption

Apart from price, range, mineral scarcity, and uncertain taxation, what else is a barrier for choosing an EV when shopping for a new car? Well, actually the most common problem I have faced in my daily use, is being “ICE’d” i.e. a car with an Internal Combustion Engine blocking a space designated for charging your EV! On this particular trip we were lucky. Only once did we get ICE’d, but luckily the cable was long enough:

In line of what I said in the beginning — this story will very soon be a tale of “the good old days” with the coming of the 350 kW charging network.

4 thoughts on “The Longest Possible Trip In One Day — With The Shortest Possible Range

  1. That was enjoyable to read, although it sounds like it wasn’t much fun for those involved. Personally, I would charge above 80% if I thought it worthwhile, if charging opportunities are scarce and range an issue, such as journeying far from the supercharger network.

    1. Good point John. I’ve added the notion about how the BMS slows down charging significally above 80% thus making the wait unbearable. With the next charger within reach, better to just get moving, in sake of my tormented wife and kids 😉

  2. An interesting point is regularly discussed by Tesla Björn that Chademo chargers are limiting the maximum current not power, usually 120A. And so the fastest charging strategy on road trip is to always charge up to 80% or the point where the BMS slows down the charging, because of higher battery voltage at higher SOC and thus higher power of charging. It should be faster from 60% to 70% than from 20% to 30%.
    It’s harder to try this out and prove it in EVs that do not show the actual charging speed which are all but Tesla. But the theory is simple and plausible. I have to still try it and record the stats.

  3. More than one fastcharger available…
    One of the reasons I appreciate Fastned fastchargers (Netherlands) so much, there are always two working/well supported fastchargers available, plus multiple options for charging passes, internet charging app etc. (.. and future ready, easily expandable to at least 4 fastchargers with higher charging speeds..)

    Charging above 80%…
    BTW our 2015 30kWh-Leaf battery charges apparently much faster above 80% than the 24kWh version. We always fastcharge our 30kWh Leaf to at least 90%, from 20%-> +90% takes allin 25 to max 30 min. Nissan apparently knows howto optimize I guess…

Leave a Reply

Your email address will not be published. Required fields are marked *