The Need for Speed

DCFC cost money more but saves in the long runSpeed is intoxicating.  Speed is alluring.  Speed is memorable.

Speed is also expensive.

Which brings us to today’s question: in the world of EV charging, is speed necessary?

The answer is…sometimes.  I’ll explain.

Using high power DC Fast Chargers minimizes the amount of time it takes to charge your commercial EV fleet vehicle.  The faster you charge your fleet vehicle, the sooner it gets back on the road, doing the things you need your fleet to do.  And that’s good.

But it’s also bad.  And potentially expensive.

Using DC Fast Chargers at max charging speed puts upward pressure on your Peak Demand.  It can cause Peak Demand to spike significantly.  And the higher your Peak Demand, the higher the rate you will pay your utility for power.

If your fleet operates during the day and recharges overnight, you have the luxury of time.  You don’t need to charge your fleet as soon as you can.  You need to charge it so it is ready to go when the morning comes.

Dwell Time is the amount of time a vehicle will be connected to a charger.  If you are trying to get your EVs back on the road as quickly as possible, you are minimizing Dwell Time and limiting your charging options.   If you have the luxury of overnight charging and an extended charging window, you have longer Dwell Time.

And longer Dwell Time gives you options that can save you money.

Option 1: charge your EVs all at the same time, but at a slower, lower kw rate.  This reduces your overall electricity consumption at any point in time, which holds down your Peak Demand.  Lower Peak Demand lowers the rate you pay for power.

Option 2: charge your EVs at max power, but charge them sequentially instead of simultaneously.  To understand how this lowers power costs, let’s assume you have a 10-hour window to charge your fleet.  Your have four EVs, and it takes 2.5 hours to charge each one at top charging speed.  You could have four EVs consume max charging power at the same time and be done with charging your entire fleet in 2.5 hours.  Or you could have 10 hours consuming power by charging one EV at a time.  Under the second scenario, your Peak Demand for power consumption due to EV charging is 25% of what is would be if you charged your entire four-vehicle fleet at once at top speed.

Repeat after me: lower Peak Demand and you lower the rate you pay for power.

Now I’m not saying DC Fast Chargers are bad.  In fact, they give you the ability to react to life’s curveballs.  If the grid goes down for any period of time due to extreme weather or other events, charging stops.  No power, no charging.  A three-hour power outage cuts your 10-hour charging window to seven hours.  DC Fast Chargers give you the ability to overcome unexpected power interruptions and still charge your fleet in time.

Fast Chargers also give you the ability to keep operations running smoothly if one or more chargers go down.  Redundancy is provided by speed.

And by a Charge Management System (CMS) that can throttle down the speed of charging when the opportunity presents itself or throttle up speed to offset a malfunctioning charger or a power outage.  That’s the thinking that led us to develop EVauto Local Control, a CMS that manages charging holistically and in real time, whether you have OCPP chargers, Modbus chargers, or both.  That can save you money or keep operations flowing smoothly.  Or both.

Yes, it may mean sometimes charging at the max rate.  But the max rate of a DC Fast Charger is approximately 18x that of a Level 2 charger.  That speed can overcome a lot of sins, including power outages and malfunctioning chargers.

Speed comes at a price.  But it can also provide a cushion that keep your fleet fully charged and running on time.  Managing your charging speed with a CMS that reacts in real time can make that happen and save you money.

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