The Anonymous Widower

The Mathematics Of Fast-Charging Battery Trains Using Third-Rail Electrification

In Vivarail Unveils Fast Charging System For Class 230 Battery Trains, I talked about how Vivarail are proposing to fast-charge their Class 230 trains.

  • The trains are fitted with special high-capacity third rail shoes.
  • Third-rail electrification is laid in stations.
  • The third rail is powered by a bank of bstteries, that are trickle-charged from the mains or perhaps even solar power.
  • When the train connects to the rail, the rail is made live and a fast transfer takes place between third-rail and train.

So how much electricity could be passed to a train during a stop?

The most powerful locomotive in the UK, that can use 750 VDC third-rail electrification is a Class 92 locomotive.

According to Wikipedia, it can produce a power output of 4 MW or 4,000 kW, when working on third-rail electrification.

This means, that in an hour, four thousand kWh will be transferred to the train using conventional third-rail electrification.

Or in a minute 66.7 kWh can be transferred.

In Vivarail’s system, because they are transferring energy between batteries, enormous currents can be passed.

To illustrate how batteries can can deliver enormous currents here’s a video of  a guy using two car batteries to weld things together.

These currents are possible because batteries have a low impedance and when the battery on the train is connected to the battery bank on the station, the two batteries will equalise their power.

If we take the example of the Class 92 locomotive and conventional electrification, this would be able to transfer 200 kWh in three minutes or 400 kWh in six minutes.

But I believe that battery-to-battery transfers could be at a much higher current

Thus in a typical one or two minute stop in a station, upwards of 200 kWh could be transferrred to the train..

July 12, 2019 Posted by | Transport | , , , , | 6 Comments