For fleets that need to electrify a depot within a reasonable budget and timeframe, automated load management (ALM) is an essential technology. ALM is a technology tool used by fleet operators to coordinate charging of electric fleet vehicles within a total power limitation while making sure all EVs are charged and ready when needed. It changes the load calculations required by the National Electrical Code (NEC), and even enables charging on difficult sites that might otherwise be thought unviable because of their power constraints.
We have shared a lot over the last couple years about ALM and how it works. It’s one of our favorite topics; we wrote a 20-page paper about it. We believe that this technology is a critical tool to enable the rapid electrification of fleet vehicles across the world and achieve our vision of zero emissions mobility. We’ve also been doing this long enough that we know that there’s an “easy way,” and then there’s the right way to do something.
This we know for sure: to oversubscribe EV charging with ALM properly, you need local control on every site. Without that local hardware component, sites will experience failures, utilities will lose trust in the technology, and the fleet electrification revolution will stall.
Unlocking the potential of electric vehicle fleet charging
Load management is a simple enough concept to understand that a software engineer might think they could relatively quickly write a code that would do the job, and at a very basic level they can. But when ALM is used to oversubscribe the capacity of a site’s electrical infrastructure it must be considered a critical system, and all precautions must be taken to ensure that it stays online at all times. If a cloud-based ALM system fails due to an internet disruption, panels could be overloaded, creating a risk of injury or damage to personnel and property. A cloud-based software system cannot be trusted to have the reliability or the responsiveness to hold responsibility for this critical task.
A hardware component installed on the depot site solves this problem by hosting the smart charging logic of the charge management system (CMS), including all ALM settings, on the controller and communicating them directly to each charger via ethernet or fiberoptic cabling.
- Reliable
In the event of internet outage, smart charging and load management continues functioning. The controller does not need wifi to continue to enforce charging limit set point. EV charging can continue, and operators can be confident that power demand from EVs will not exceed the pre-determined set point.
- Responsive
Even during normal operating conditions, ALM provided by a CMS with a local controller will provide benefits over a purely cloud-based system. Anyone who has watched a streaming video knows that data interruptions happen, which might be fine for a show, but not for critical electrical infrastructure. A local control-based CMS makes smart charging decisions on-site, removing the time it takes to send data and receive commands from the cloud. As we noted in our ALM Technical Guide, “Local controller based ALM systems can achieve speeds of control of 4 to 14 second reaction times, significantly faster than the 2x reaction times of a fuse at 20 seconds.” This allows the system to make real-time adjustments to changing conditions such as non-EV facility load.
The primary advantage of a cloud-based system is the convenience of remote monitoring. The most advanced CMS systems, such as ChargePilot, do include a cloud-based dashboard interface along with on-site local control. While there is an incremental cost to install these components, over the lifetime of an EV fleet charging depot, our 1700 fleet depot customers have found that is sure to be a worthwhile investment.