Unmasking the Truth: Why Most Fast Chargers Fall Short of Their Promised Power

The big lie: Most 120kW, 180kW, 200kW DC fast chargers are only supplying 80kW of power

In the race for market share, funding dollars, and a geographic footprint, we as consumers have been lied to about public fast-charging infrastructure!

Last winter, when founder Mark MacDonald was driving from Halifax, Nova Scotia to Moncton, New Brunswick in our company Ford F150 Lightning, he did what most non-Tesla drivers would do and began planning his route using a combination of Google Maps, the PlugShare app, some meteorological voodoo, and, as his business partner describes, a dance with a chicken bone necklace – all in the hopes that his journey would be seamless and his charging stops short, efficient, and perfectly timed. 🤞

Ford F150 Lightning Parked Downtown Street

This was his experience...

As I was viewing the public charger map before hitting the road, I was excited to see a 200kW DCFC charger at a Petro-Can along my route. This would be the perfect stop, it featured two CCS connectors, so I wasn't too worried about arriving to find someone else had beat me to it, and at 200kW, I'd be able to charge 4 times faster than certain commonly-found brands of DCFC available in our region. I'd be charged up and back on the road in no time. 

During the journey, the variability of temperature quickly came into play so I knew I was going to need a little longer on the charger, but not much, and with 200kW of power available it should only add about 5 minutes more of charging.

When I finally arrived, the charger was empty so I started the session with a credit card payment in the terminal, hopped back in the cab, and watched the console on the vehicle to see the charging speed slowly creep up, 10kW... 20kW... 40kW... 80kW… 80kW… 80kW!! What gives? This 200kW rated charger would not supply more than 80kW. Thinking something must be wrong with the connector, I end the session, switch to the other connector, and start again. 10kW... 20kW... 40kW... 80kW… 80kW… 80kW!! I was trying to wrap my head around what could be happening. Maybe it was the battery management system on the vehicle... Time to do some research!

After confirming that there was nothing wrong with the vehicle, the truth of the kW lie of DCFC reared its ugly head. The reason my vehicle could only get 80kW on a 200kW rated fast charger is because the manufacturer of that charger used a CCS supply cable and connector that was only rated for 200A.

“What does this mean oh great fast charging Guru?”

I’m glad you asked. To understand my fast-charging problem, we need to go back to our old German friend Georg Simon Ohm and his famous Ohm's Law. You see, power is a function of Amperage times Voltage. So even though the charger is capable of supplying 200kW, the voltage in my Ford F150 Lighting DC battery system is 400V.

In the rush to deploy infrastructure, there's been a lack of adequate engineering. Likely to do with trying to keep cost down (lowest bidder tenders and all), and this has resulted in us having an abundance of of DC fast chargers out there with only 200A supply cables.

Lightbulb moment - so this is what happened to me at the chargers I was trying to use at Petro-Can!!

Let’s look at the math:

Petro-Can Charger = 200kW

CCS Supply Cable/Connector = 200A

Ford F150 Lighting Battery = 400V DC

Cable 200A x Battery Voltage 400V = 80kW

Maybe I’m alone in my Ford battery voltage shortcoming? Turns out, I’m not. In fact, almost all electric vehicles in North America use 400V batteries in the architecture - including Tesla. The only exceptions to this rule are Kia, Hyundai, Audi, Porsche and Lucid. 

So how do we overcome this false advertisement of available power?

The first step is to start publishing the CCS cable amperage on the networks, so we as consumers can make better decisions about where to charge.

Secondly, we need to look at different hardware for the DCFC infrastructure deployments. The chart below gives you some examples of charge times per vehicle and charger. You can see where the value in the 800V batteries starts to shine when comparing 75kWh batteries in the Tesla Y to the Hyundai Ioniq 5. It drops the charge time by almost 15 minutes when plugged into a 180kW charger fed from 300A CCS Cable!

If cable amperage (not kilowatts) matters, then what are your cable amperage options? For anyone involved with the specifying of CCS cables on chargers above 80kW, we have a few: 200A, 300A and 400A. All of which are what is referred to as air-cooled, or naturally cooled. We also have a 500A CCS cable that is liquid-cooled, offering more power at a lighter weight with significantly more components, however, at a greater cost.

Here is a great breakdown that I stole from somewhere on the internet (I tried to find it to give proper credit, but a reverse image search didn't turn up any results) that shows charge times by battery voltage and cable type when plugged into a 180kW DCFC:

So what hardware is the best?

Here at Electric Avenue, we offer multiple charger and cable options - but more importantly, upgradability as your requirements change!

Our Watti Direct 120kW Upgradable charger offers a 300A air-cooled cable, ensuring all 400V vehicles in North America can receive the full 120kW during a charge. This 120kW Upgradable charger can be updated to pump out 180kW with the quick addition of two 30kW power modules as your needs demand. Did we mention our cables are also replaceable? Start with a CHAdeMO cable today as the second cabling option, and swap it out tomorrow for another 300A CCS cable as the needs of your customers or fleet change.

Don't forget the software! Through our Enterprise+ software, specifically for DCFC, you can monitor, control and manage your chargers through an easy to navigate online dashboard.