EV BATTERY FAQS
Frequently Asked Questions About High-Voltage EV Battery Health Tests
EV BATTERY SOH TEST FAQS
Frequently asked questions about high-voltage EV batteries, battery health tests, and safety concerns
How do I check the battery health of a used EV?
Commercial-grade diagnostic equipment is required to accurately test the battery health of a used EV. Schedule an appointment with the manufacturer’s service center or a licensed EV battery health diagnostic shop or mobile EV battery service like EV VERIFIED, Inc.
Where can I get an EV battery test near me?
EV VERIFIED provides EV battery State of Health, SoH, tests in Southern California. A complete list of licensed EV service centers nationwide is coming.
What's a good EV battery State of Health for a used EV?
If 100% is new State of Health, SoH, and 70% is End of Life, EOL, then EV battery SoH with 85% might be considered 50% of usable life remaining. But degradation of the battery is not linear there could be more loss or less depending on battery chemistry and management habits. However, reports on NMC batteries cite 2% loss of SoH per year as normal. So 92% SoH after four years would be normal for battery SoH loss barring outside influences. So battery degradation is not uniform and depends on battery chemistry. battery management, vehicle use, tires, and other factors. Most importantly, high mileage is not always an indicator of poor battery SoH.
How much does an EV battery health test cost?
Commercial-grade battery tests can be $350-$1,200 and are often sold as part of a larger diagnostic package. EV VERIFIED battery SoH tests are designed to be the best value for mobile, rapid SoH tests.
How long do EV batteries last?
EV battery lifespan is determined by numerous factors including battery chemistry, battery management practices including how often the battery is charged and to what percentage, and the State of Charge, SoC, when the EV is at rest. Some studies on NMC batteries, (used frequently in long-range Teslas, Rivians.and Lucids), have been shown to last 400,000 miles when the SoC was kept between 40%-60% in a controlled study.
How much battery capacity does an EV lose each year?
2%/year of EV battery loss is common without undue stress.
Should I get the battery tested before I buy a used EV?
You should always test the high-voltage drive battery on a used EV before buying. The cost of a replacement battery averages $15,000 and the SoH of the battery is dependent on the battery management habits of the previous owner(s). Used EVs coming off of lease programs are particularly worth testing as those owners may not have been as attentive to proper battery management practices resulting in faster degradation than used EVs that came from a single owner who was diligent about battery health and paid attention to the State of Charge, SoC, during charging and at rest.
How much does it cost to replace an EV battery?
High voltage EV battery replacement averages $15,000 from the manufacturer although some independent shops may offer replacement for some models for under $10,000.
What does battery State of Health, SoH, actually mean?
SoH, or State of Health, represents the remaining battery capacity to hold energy.
Can I test my EV's battery health myself?
Yes you can test your EV’s battery health for some makes and models. Tesla provides guidance on how to test the SoH of your EV battery which requires charging it to 100% and then draining that charge. That process, however, degrades the battery. Some Tesla DIY tests also run the risk of “bricking” or freezing the EV according to some reports. An independent, licensed diagnostic technician using a rapid, mobile EV battery test like the AVILOO diagnostic tool will yield accurate results without any degradation. The EV VERIFIED service provides this test for less than it costs you to do it on your own while connecting the owner with other related EV options. Over the counter, OTC, options available for sale online do not read SoH data at the cellular-level and therefore do not provide accurate SoH percentages.
Can someone come to my home or dealership to test my EV battery?
EV VERIFIED dispatches licensed EV battery diagnostic technicians to private parties at their work or home, to dealer lots, fleets, and auctions to test EV inventory as part of monthly maintenace programs.
Is the range shown on the dashboard an accurate measure of battery health?
EV range listed on the vehicle screens is calculated by the Battery Management System, BMS, based on past and current driving and charging habits as well as tire types and conditions along with other factors. These range numbers are live estimates, not an SoH measurement of battery health.
How do I check the battery health of a used Tesla?
Tesla battery State of Health, SoH, can be tested in three ways: 1. The TESLA TOOLBOX is the OEM diagnostic used by Tesla technicians. 2. DIY Tesla battery SoH tests following OEM guidance and requiring 24 hours to complete. 3. AVILOO Flash Tests performed by a licensed diagnostic service like EV VERIFIED.
What is a typical battery health percentage for a four-year-old EV?
A typical EV with an NMC or similar EV battery will lose 2% SoH per year under normal conditions and proper battery management practices.
Is 90% battery SoH good and how much range should I expect?
90% SoH is FAIR to GOOD and considered average for NMC batteries on four-year-old EVs with 100,000 miles. While EOL is 70%, 85% does not mean 50% of usable EV battery remaining anymore than 90% equates to 66% battery capacity remaining because battery degradation is not linear. However, 90% does not mean 90% of EV battery capacity remaining but rather 90% of the total battery capacity. At 2% average degradation for NMC batteries in the first four years, normal loss would deliver a 92% SoH.
Does frequent DC fast charging damage an EV battery?
The data is still coming on how damaging DC fast charging is to EV battery health. However, EV Battery Management Systems, BMS, are designed to rapidly heat or cool the battery before fast charging. This process is designed to condition the battery to handle the energy input without damaging the battery itself. What is undeniable about EV battery SoH is that charging your EV battery to 100% or draining it below 20% on a regular basis causes degradation to the cells by stressing them. So it is possible that DC fast charging does not damage the high-voltage battery in and of itself as much as some have suggested but charging over 100% and going below 20% consistently damages the battery, But not all batteries are the same and not all BMS are the same. LFP batteries are intended to be charged to 100% weekly in order to balance the cell pack while NMC batteries are recommended to avoid charging above 70-80% depending on the OEM.
Is charging an EV battery to 100% bad for the battery?
Charging to 100% is not necessarily bad for the battery. LFP batteries require 100% charging weekly to balance the battery pack. But charging to 100% and leaving the EV sitting without driving at any State of Charge, SoC, above does damage the battery. Tesla provides a scheduling option to have your battery charging complete as you are ready to leave in order to avoid having the EV sit at a high SoC.
Which used EV's have the longest lasting batteries?
EVs with LFP batteries last the longest.
Are LFP batteries better than NMC batteries for longevity?
Existing data supports LFP as longer lasting than NMC and because they lack Cobalt, LFP batteries are also less expensive bringing EV costs down.
Can an EV battery health test detect bad cells or hidden battery problems?
Deep dive CARA Certified third-party tools like the AVILOO and OEM diagnostic tools like Tesla Toolbox and Rivian R1DE software can detect bad cells and other EV related battery problems.
How accurate are EV battery health tests and which method should I trust?
OEM and some third-party commercial-grade tools including Autel and AVILOO are accurate and can be trusted to deliver cell-level EV battery SoH measurements.
Will the manufacturer replace my battery if its health drops below 70%?
Yes. If the battery is under warranty the OEM will replace the EV battery. However, battery warranties also include mileage. Tesla warranties EV batteries at 100,000. 125,000, and 150,000 miles while Rivian warranties their high-voltage EV batteries at 120,000, 150,000 and 175,000 miles. So if your EV surpasses that mileage and then the battery SoH falls below 70% you will be out of warranty for that replacement. A Rivian large pack replacement battery is quotes at $30,000 for the battery alone plus labor.
Does a verified EV battery health report increase a used EVs resale value?
Yes. A CARA certified battery report has shown EVs sell faster and for more than non certified EVs.
How do hot and cold weather affect EV battery health?
Cold temperatures cause a temporary drop in range while prolonged heat causes permanent loss of maximum capacity and shortens the overall lifespan of the battery pack. Park your EV in the shade whenever possible.