SOH test: the State of Health of every EV battery in 3 minutes
Certainty through proof. Receive objective data on the current state of any battery pack in just 3 minutes.
— THEORY VERSUS REALITY
What is the State of Health of a battery?
The transition to a fully electric car (EV) or a Plug-in Hybrid (PHEV) still raises understandable questions for many consumers and businesses. The biggest question marks almost always revolve around the condition of the battery pack. Is the battery still good? What if it breaks down soon? At The Battery Experts, we understand that as a buyer or seller, you do not want to gamble on assumptions. You want solid certainty about the lifespan. That is exactly what we deliver. Our philosophy: no doubt, only proof. The overall health of the battery pack, internationally referred to as the State of Health (SoH). This state of health of an electric car directly determines the maximum range and the status of the vehicle's battery pack. We believe in absolute transparency. With objective data, reliable equipment, and clear explanations, we stand alongside our customer. We are guiding, but never patronizing. No fine print or sales hype: what we measure, we say. In this comprehensive guide, we explain in detail how we translate complex battery data into one understandable conclusion, how the State of Health is precisely calculated, and how private individuals and car companies directly benefit from our certified report. Private individual? View what we do for consumers.
— WHY
Why the SOH value is so crucial
The term SoH is simply the international technical abbreviation for State of Health. This is a percentage that compares the current maximum energy capacity of the battery pack with the original capacity on the day the car left the factory. To illustrate: a SoH value of 100% means the pack is in absolute brand-new condition. Should this percentage drop over time to, for example, 85%, this effectively means there is 15% degradation of the battery cells. According to a large-scale, reputable study by Geotab and Arval (among thousands of electric vehicles worldwide), the average battery degradation of a modern electric car is about 1.8% to 2.3% per year. This is a reassuring fact for many. However, this is an average; the exact wear and tear varies enormously by brand, year of manufacture, and charging behavior. Anyone who structurally charges their car to 100% on a fast charger often sees faster degradation. Replacing a defective battery pack can easily cost between €7,000 and €15,000 or more in practice. It is therefore downright unwise to rely blindly on assumptions during a transaction. The determined SOH value of the battery, together with our in-depth analysis including an analysis at the cell level and a final judgment of the battery in the form of a traffic light principle, therefore forms the crucial and hard indicator of the fair residual value and reliability of the car. You will encounter this measurement under many names: SOH test, state of health test, SOH electric car, state of health electric car, SOH car, state of health car, SOH battery, SOH battery car, or state of health battery car. It always refers to the same thing: a single percentage that states how much capacity the battery has left. The SOH in electric cars drops on average by 1.8% per year.
— THE SOH VALUE
SOH measurement of electric cars: theory versus reality
Many owners and sellers mistakenly believe that the range displayed on the dashboard (the so-called 'guess-o-meter') provides sufficient insight into the battery condition. This is factually incorrect. Indeed, this projected prediction fluctuates rapidly based on recent weather conditions, previous driving style, and the outside temperature. In winter, cold weather can make a battery seem severely degraded, when this is purely a temperature effect. If you want to measure the battery health of an electric car in a factual, down-to-earth way, you have to go to the original source: the Battery Management System (BMS). This system is the smart 'brain' of the battery pack that continuously tracks voltages and resistances. A professional assessment of the State of Health therefore requires us to safely read this brain and interpret the data. Accurately mapping the data of electric cars is done via the commonly known OBD port, which is present as standard in every vehicle. By analyzing the data from this, not only is the remaining total capacity made visible, but critical factors are also assessed, such as any unbalanced voltages across the individual battery modules. We filter this raw and complex mass of technical data points and present one reliable and clear final result.
— THEORY VERSUS REALITY
How do you perform an SOH test in practice?
Every day, we receive the same core question from both consumers and car companies: How do I check the SoH of an EV battery without complicated procedures that leave the car unusable in the workshop for days? Our testing process at The Battery Experts for the state of health test is specifically designed for this. The procedure is as follows: you simply connect our specially designed TBE Toolkit with an OBD dongle and adapters for Teslas, among others, to the OBD port. From that moment on, our measuring equipment communicates directly with the car. This means manufacturer warranties are never compromised. Because every car brand uses its own security and complex software protocols, it is crucial that we can read through these encryptions. Where a standard cheap error code reader from the internet gets stuck, our professional toolkit retrieves the specific, hidden data packets that reveal the actual cell condition. Without a technical background, you can effortlessly perform a full SoH test this way. In no time, you will have the exact status of the SoH in your hands, regardless of whether you are examining a Tesla Model 3, a Volkswagen ID.4, or a Nissan Leaf. View all supported models.
— WHY
How fast is a state of health battery test?
In a commercial environment such as a car dealership, or during an exciting pre-purchase inspection by a consumer, time is scarce. The frequently asked question 'how fast can an EV battery be tested?' is therefore completely justified. With outdated systems or competing providers, a time-consuming dynamic test method is often prescribed. This requires a driver to literally drain the battery from 100% to 10% in order to make a calculation, or testing must be done under special conditions. This process easily takes hours or even days, requires extra insurance, man-hours, and places a heavy logistical burden on the used car dealership. With us, this works considerably faster. By using a static SoH measurement via the BMS, we simply offer the fastest test on the European market. Within a maximum of 3 minutes, you have a definitive result without depending on how full the battery is. The data we retrieve from the car is interpreted and compared with our own extensive database. This makes our battery State of Health test not only spectacularly faster, but also ensures that the outcome is highly reliable.
SOH software electric car: the foundation of reliable data
Physically connecting hardware to a vehicle is only the first step; the real magic and reliability lie in the software that interprets the data. Advanced SoH software is simply indispensable for deciphering and standardizing the raw manufacturer data (often incomprehensible hexadecimal codes). Car manufacturers often make reading their battery data deliberately highly complex by building in firewalls and constantly changing firmware updates. Our patented software has been developed from the ground up to function continuously and across brands. The detailed data we obtain via our dongle and app is analyzed at lightning speed and encrypted in our cloud environment. Within a matter of seconds, the translation takes place into an insightful, reliable score of the State of Health, an individual cell overview, and an assessment of the battery's status. What fundamentally sets us apart is that we are CARA Approved; the official and strictest European standard for this type of diagnostics. For you as an end user or garage owner, this gives the ultimate confirmation that the obtained SoH value is objective, and the results will be effortlessly accepted throughout the entire remarketing chain.
From measurement to state of health report
For major brand dealers, leasing companies, and car companies, we understand the need for scalability and have therefore built a powerful API integration . With this digital integration, the results of every battery test flow directly and fully automatically into your existing back office, such as a Inventory Management System (IMS) or other systems. How does this work in practice? As soon as your inspector or mechanic plugs the dongle into the vehicle and synchronizes the app, our server not only pushes the generated State of Health report as a PDF to the cloud, but all raw measured values (including exact remaining capacity, cell voltages, and the calculated State of Health as structured data points) are linked to the chassis number (VIN) in your own database. This immediately makes the vehicle file 100% complete and prevents administrative hassle.
A report that nobody gets to see ultimately achieves very little. How you deliver the certificate to the buyer, whether via an integration with your own systems or as an image among the sales photos, you can read on the page about SOH integration.
API integrations
PDF SOH report
JPEG Battery Report
VIN linked
CARA Approved
— COMPARE
What do you look for when choosing SOH equipment?
In a fast-growing market full of battery diagnostics, we focus entirely on quality and reliability. With our CARA-approved equipment, we guarantee speed, comprehensive coverage, and accuracy with every state of health check. Our solution enables you to quickly and conclusively determine the residual value of the car's SoH, supplemented by additional margin products such as the EV delivery package, so you benefit optimally on the work floor without being dependent on slow external helpdesks.
Frequently asked questions about SOH
What is a battery certificate and why do I need one?
A battery certificate is an independent report on the health (State of Health) of an electric car’s traction battery. The certificate shows, among other things, the remaining capacity, cell balance, and charging history. When buying or selling a used EV, this increases buyer confidence and leads to a higher residual value and faster sale.
Which vehicle models can be tested?
Do I need special technical knowledge to perform a battery test?
How long does it take to perform a diagnosis?
What does the SoH value (State of Health) mean?
Can the test equipment change or damage my car's settings?
What causes the battery of my electric car to deteriorate or degrade?
Can the battery certificate be used in legal disputes?
Which app should I download to take the test?
What exactly do I need before I can use the app?
— Start directly
Measuring SOH yourself: this is what you need
For everyone involved in the purchase, sale, or management of electric vehicles, one thing is certain: peace of mind regarding the most expensive component of the car is priceless, but its reliable inspection doesn't have to be expensive at all. We have made the technology simple. We translate inaccessible data streams into one crystal-clear conclusion. We warmly invite you to contact us for a demonstration without any obligation. Discover with your own eyes how we create a structurally higher return on every used vehicle through lightning-fast hardware, robust API solutions, and by unburdening your technicians. We don't promise miracles and we don't do fine print: what we measure is what we say. Get in touch today and help build a reliable and sustainable EV market.
The three versions of the TBE Toolkit
One-time purchase, no subscription. You pay € 29.95 excl. VAT per performed SOH test, billed monthly in arrears.
