Category: Electric

Preparing the charging infrastructure for the Tesla Roadster

As you might have read, a friend of mine (also my colleaugue) has ordered a Tesla Roadster, so we had to do some preparations for the charging infrastructure.

We live in The Netherlands (Middelburg, Zeeland) where we have two offices. Our main office is at the city center, but we also have second office which is outside the city and has a private parking deck, ideal for charging your Roadster!

One of the problems you have in Holland is that our whole infrastructure is based on 3-phases, while the Roadster only supports 1-phase charging. A lot of offices are connected to one or more phases with a 25A or 35A breaker (one breaker per phase ofcourse). Yes, we have 230V, so 35A should give you around 8kW of power, but it would still take 6.6 hours to fully charge the Roadster. But that is the situation here, you can’t use more than 32A (breaker is at 35A) on one phase. The 3-phase system has to be balanced, so when you want to use more then 32A, the load should be spreaded over the 3-phases.

Our office had one breaker of 35A, which was enough for just the office (5 desks and some servers), but it wouldn’t be enough for charging a Roadster. After contacting the utility company they told me that the first step was to go from 1x35A to 3x40A, so that is what we did.

That was our old main breaker, as you can see, there are two (Black and Grey) unused phases, the utility company came over and they connected the two extra phases and installed a 3-phase kWh meter.

After that was done we contacted a local electrician who could expand our fusebox. Since I made a reservation for a Model S, we choose to use both extra phases for charging EV’s.

This resulted in two charging stations of 230V 32A at the parkingdeck, both connected to their own 32A breaker. After there work was done, our fusebox looked like:

At the parking deck we installed two 32A single phase sockets, we have two parking places next to each other


The connector which we will be using to charge the Roadster is a CEE Form 32A Single Phase connector:

Compare that to the 16A connector:

While charging stations are being installed more and more, they are not everywhere. Every outlet in the wall is a charging station, so why not use it? I created some converters which would enable him to charge his Roadster anywhere:

I’m still waiting for some connectors to create a 3×32 to 1x32A converter, but it’s the same as the 3x16A to 1x16A converter showed above, but then a bit bigger.

For now, we only have to charge this Roadster:

To be continued!

Quickcharging an EV, how much power do I need?

There are two points on which people criticise Electric Vehicles (EV):

  • Their range
  • The time it takes to charge them

The first can be solved by ‘simply’ adding a larger battery, this can be in physical size or having more Wh’s (What Hours) per Kilogram.

Filling the tank of a car with a ICE (Internal Combustion Engine) takes about 3 minutes, it is something we are used to. But charging a EV can take up to several hours.

A lot of people say that they will start driving an EV as soon as the range gets better or charging can be done fast, like they are used to right now.

Charging a EV really quick has a few problems which can not be solved that easily:

  • The batteries can’t be charged that fast (Yet)
  • It takes a lot, really A LOT of energy to charge that fast

Take a Tesla Roadster for example, this car has a 53kWh battery pack. 53kWh equals to 190800000 Joule (53 * 1000 * 3600). If we want to charge this battery in 5 minutes, we would need to put 636000 Joules per second into that battery. 636000 Joule equals to a current of 636kW (636000 / 1000).

A simple micro-wave in your kitchen uses about 1kW of energy, charging a EV that fast would use the energy of 636 micro-waves! That would put a lot of stress in the grid, too much stress.

If we charge the EV in 10 minutes we would ‘only’ require 318kW of energy, 20 minutes 159kW and 30 minutes would take 106kW of energy. Those are still high numbers, but they come closer to what is possible.

Take the Nissan Leaf for example, this car has a 24kWh battery which can be charged to 80% in 30 minutes, let’s calculate how much energy we would need.

80% of 24kWh is 19.2kWh, that equals to 69120000 Joule (See my calculations above). 30 minutes equals to 1800 seconds, so charging in 30 minutes requires 38400 Joule per second, or 38.4kW of energy.

Charging that quick will mostly be done at 480 Volt. 38400W / 480V = 80A, that is how much we need to charge a Leaf that fast.

3-phase 480 Volt is not that hard to find / get here in Europe, so charging a Leaf that fast is feasible on a lot of locations.

Not only will quickcharging put a lot of stress on the grid, it would also be unsafe for humans to connect such cables. If the current which flows through that cable would be exposed to a human, you would instantly be killed, no doubt.

Quickcharging a EV has a few drawbacks, let’s sum them up:

  • Bad for the battery

  • Puts a lot of stress on the grid
  • It would be very dangerous for humans to handle such cables

But why would we want to do that? A EV can be charged everywhere! Your car will be parked for most of the time during the day. Those are all possible charge possibilities, we should work towards utilizing those moments. Ofcourse, there will be some places where quickcharging will be possible, but I think they will be placed on strategic locations like road-side restaurants.

I think we need to let go of the concept of filling up our car within a few minutes. In the future battery technology will improve and we will start to see battery packs ranging from 75kWh to 150kWh, which will bring us where we want to go, charge there and get back again.

Tesla Roadster coming soon!

While I’m waiting for my Tesla Model S a friend of mine just bought his Tesla Roadster 2.5, cool!

He choose the Fusion Red color with the executive interior, what a gorgeous! A few pictures below.

While it’s a beautiful machine, it’s also fast and eco-friendly! If you read my blog you might notice that I’m into EV’s, not because I’m such a “environment hippie”, but I simply like the technique behind it.

Right now we are working on getting the fuses at our office upgraded from 1x 35A (230V) to 3x 35A, so that we can use 32A’s charging the roadster.

One of the interesting things is that we live in the Southern part of Holland (Zeeland, Walcheren to be exact) and we need to travel to Amsterdam quite often. While the roadster should get there (220km) with it’s 350km range, we are curious how much energy we will be using, since it’s all highway (120km/h) driving.

In Amsterdam we will also create a 32A socket for charging the roadster, so that we can make the round-trip without problems!

I’ll keep you updated!