Not All Remote Dispenser Architectures are Created Equal
Joseph Gottlieb, CTO, Tuesday August 17, 2021
Our last blog explored when it makes sense to connect multiple dispensers to a single power control system (PCS) – generally the largest (and most expensive) component of the electric vehicle (EV) charging infrastructure. Assuming that you have a use case where a shared PCS makes sense for your fleet, the natural question to ask would be “are all multi-dispenser solutions equal”? In fact, there are significant differences in the architectures for multi-dispenser deployments, but at a high level there are two specific approaches: parallel-connected dispensers and serially-connected dispensers. We will explore both in this blog.
As the name implies, the parallel-connected approach powers multiple remote dispensers from a single PCS, with a dedicated connection (e.g., high-voltage DC power feed) from the PCS to each dispenser. Since nearly all parallel approaches today only power a single dispenser at a time (more on that in next week’s blog), high-voltage DC switching circuitry is required to switch the PCS feed from one dispenser to another (this circuitry is typically located next to the PCS). A dedicated trench is then dug in the vehicle lot from the DC switch gear to each dispenser. The serially-connected approach also powers multiple remote dispensers from a single PCS, but utilizes only one high-voltage DC power feed to connect the PCS and all of the dispensers (the feed runs from the PCS to the first dispenser, and then runs serially from that dispenser to the next dispenser until all are connected). In this approach, each dispenser contains a two-way power switch. The primary advantage of the serial approach over the parallel approach is that it significantly reduces the number of trenches that need to be dug, and cable that needs to be laid, during installation. At prices that can reach $10,000-$20,000 per 1000 feet of trenching, there can be significant cost savings by using the serial approach. If you are looking for made in the USA high-power DC fast charging systems for those EVs, look to Rhombus Energy Solutions. Our market-leading bi-directional EV charging systems (which are designed from the start for the needs of fleet operators) are designed and built in the USA. Rhombus also excels in the design of high-power smart inverters for next-generation renewable energy and energy storage deployments. Our expertise in energy management system (EMS) software is also embedded in our VectorStat EMS controller and software which is embedded in our EV charging systems and smart inverters. We have built over a thousand V2G-capable high-power, high-reliability chargers and bi-directional smart inverters for a variety of different sizes and classes of EVs.