The Biggest Lie in the EV Industry: Why “Range” Does Not Equal “Battery Health”
By: Joel Davis, Founder and Lead HV Specialist, Elektrowagen Consulting LLC
If you are shopping for a used Electric Vehicle today, you are being sold a massive, industry-wide lie.
It goes like this: You look at the car’s dashboard. You look at its remaining range, you do some quick math and conclude, “Great, the battery has 87% health!” Companies like Recurrent use this exact telematics data for their reports. Apps like Tessie and cheap Bluetooth dongles use it. Even Tesla’s own onboard screen feeds you this calculation. The entire EV industry has accepted this oversimplified math as the absolute truth.
There is just one massive problem: Range and Battery Health are not the same thing.
Let’s put this in perspective. Measuring an EV’s battery health by looking at its remaining range is exactly like trying to determine a gas car’s engine health by measuring the size of its gas tank.
A 15-gallon gas tank tells you nothing about whether the engine has a blown head gasket, a cracked block, or failing pistons. So why are we trusting a “range estimate” to tell us if a high-voltage battery is structurally sound?
The Hidden Killer: Cell Imbalance
EV batteries are not just one giant bucket of electricity. They are comprised of thousands of individual cells grouped together into “bricks.” The true health of an EV battery isn’t about the total amount of energy it can hold. It is about balance.
You can easily have an EV battery that boasts 90% of its original range, but lurking deep inside the pack is a single failing brick with internal issues.
For a long time, the car’s internal computer (the Battery Management System, or BMS) will work overtime to mask this bad brick, balancing the power so the car feels completely normal to drive. The apps will say you are fine. The dashboard will say you are fine.
But the moment that single brick degrades past the threshold where the BMS can hide it, the illusion shatters. The system throws a cascade of fault codes. Your car doesn’t just lose a few miles of range—it completely bricks itself. Suddenly, you are sitting at a service center staring down a $15,000 replacement bill for a battery that your app promised was at “90% health” just yesterday.
Stop Checking the Gas Tank
The EV industry has accepted the lazy math of “Original Range vs. Current Range” because it is cheap, easy, and can be done wirelessly from the cloud.
But if you are buying a used EV, or trying to evaluate your own vehicle before the warranty expires, looking at the dashboard range is a dangerous gamble.
Don’t trust an app. Don’t trust a $50 dongle. And don’t trust the dashboard screen. If you want to know the truth, you need a professional, direct-connect dynamic load test to bypass the software and see how the physical hardware is actually performing.
Stop measuring the gas tank, and let’s actually check the engine.
*** (Need to know the truth about your battery? Visit ElektrowagenConsulting.com to book a direct-connect dynamic scan in the Denver area).