Looking at medium and heavy duty electric trucks, the batteries on the trucks get bigger and the operator has to start going to higher power systems which can be provided by DC chargers systems. DC chargers start at around 20kW, but can go as large as you need. There are 600kW DC chargers available in the Australian market if you need them.
Although it may be desirable, there are some disadvantages to moving to higher power systems, in particular, the electrical infrastructure the operator needs to have in place to deliver the AC current to the chargers.
“As you step back from the interface between the vehicle battery and the charger, you start to look at the rest of the system and how it needs to develop,” says Alex Bowler, Business Development Sector Manager for bus and truck at JET Charge. “The charger needs to be fed power from a distribution board, or the sites main switchboard (MSB). Many small commercial sites or depots will have an MSB and grid connection sized between 250 and 1000 amps (A)
“A 200 kW charger uses around 320 amps, so if you want to charge one truck, you are either almost using up your entire electrical capacity, or you might be able to charge two or three trucks at the same time. Because you can be constrained by power, you need to have a good idea of when and how much you’ll need to charge. We have also developed systems which control the charge rates and make sure you never exceed your capacity. This means you can plug in all your fleet, and let the computer balance the charge rate and keep the total demand underneath a threshold.
“So when you start to scale up to high power charging across more of your fleet, it’s often the case that your current distribution and capacity is not big enough. Then you will need to put a new connection in and new switchboards which can really increase your infrastructure costs.”
It does cost quite a lot, but in the total cost of ownership analysis JET Charge have done it’s still cheaper than diesel to upgrade the site, finance it, and have a lower operating cost through fuel savings. Also, once you’re at this scale, the cost per charging bay is marginal.
There are some big changes in store for transport and logistics depot sites across the country. It’s important to know though that the infrastructure requirements are standard fare for the electrical industry. It is all a known quantity. The technology available today will be capable of keeping a fully electrified pick and delivery local truck fleet on the road. Overnight and opportunity charging with current technology is available now.