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Everything You Need to Know About State of Battery Health Certificates

Everything You Need to Know About State of Battery Health Certificates

Learn all about EV battery testing, SOH certificates, and how you can get one if your customer asks for it. You’ll also find why they’re useful but not mandatory.

If you’re selling electric vehicles, you may have noticed an increased interest in battery condition. More and more buyers want to know how healthy the battery is before they buy a used EV, and that’s why battery state of health (SOH) certificates are becoming a popular topic.

But, are these certificates really necessary? How do you get one? And what do you need to know as a car trader to assist your buyers?

Here’s what you need to know about battery testing, starting with what battery state of health (SOH) actually means and why it matters for used EVs.

What is the battery state of health (SOH)?

When you first buy an EV, its battery has 100% of its original capacity.

Over time, with regular use and charging, the battery slowly loses some of that capacity.

The state of health (SOH) tells you how much of the original battery capacity is still available.

For example, if an EV originally had a 65 kWh battery and now holds 60 kWh, the SOH is about 92%. This means the car can still be used normally, but it might not drive quite as far on a full charge as it did when it was new.

Knowing about, and being transparent about the state of battery health is crucial for used car traders, as that builds trust and avoids confusion about range or performance.

A SOH below 100% isn’t a problem, as long as the buyer understands what that means. Most people are fine with a slightly reduced range if they know about it in advance.

How is state of charge (SOC) different?

Along the term SOH, you’ll also see SOC when discussing batteries.

That stands for the state of charge, and it simply shows how full the battery is at a given moment. You can think of it as the electric version of a fuel gauge.

Looking at this Nissan Leaf dashboard above, you can see that its SOC was at 86% when the picture was taken.

The car’s Battery Management System (BMS) constantly monitors and calculates SOC, and you can always see it on the screen.

How is battery health measured?

So, once you decide to check an EV’s battery health, how do you measure it?

You’ll start by buying a SOH solution from a specialized third-party company.

One of the options you can use is AVILOO, an Austrian battery diagnostics company that works with customers across Europe.

Regardless of the test provider, you’ll first plug a diagnostic device that you’ve purchased into the car’s OBD port. It’s usually located under the dashboard, like in the video below.

The device connects to the car’s BMS and collects battery data such as:

Voltage
Temperature
Charging history
Current usable capacity

The tool then runs a diagnostic session and calculates the state of health (SOH). Most battery test providers will require you to drive the car or perform a full charge during the test for more accurate results.

When it’s done, the system generates a PDF certificate with the SOH percentage and other battery details.

An example of AVILOO’s battery certificate

You pay for the hardware and the test separately, but once you have the tool, you can use it on multiple vehicles. It’s a practical solution if you want to give your customers a reliable battery report.

Are battery health certificates necessary?

Short answer: no.

Unlike COC certificates, battery health certificates are not mandatory when buying or selling a used EV.

Some traders issue certificates for customers who want proof of battery condition. But in most cases, if you’re buying used EVs from trusted suppliers, battery health won’t be an issue.

In fact, a recent Arval study showed that EV batteries still retain over 93% of their capacity even after 70,000 km of use.

So, SOH certificates aren’t considered as standard documents.

Some suppliers choose to include them, but most clients don’t need them unless their own buyers specifically ask for one.

❗Most of the cars sold on eCarsTrade don’t come with battery health certificates. If they have a certificate, you will see a photo of it in the photo gallery of the car.

How to get battery certification?

If the EV you’re buying on eCarsTrade doesn’t come with a certificate, but you want one, your best option is to buy a diagnostic tool and then use it with a certified battery testing provider.

Doing so will help you add value to your listings because battery certificates give buyers clear information about battery condition. Also, you won’t have to rely on the supplier as you’ll be able to check the battery yourself whenever you need to.

Lastly, SOH certificates can help you justify your pricing. If the SOH is high, you can confidently ask for a better resale price.

Now, let’s go over SOH certificate providers by country.

► How to get battery SOH in France?

UTAC provides EV diagnostics and SOH testing.

► How to get battery SOH in Spain?

If you’re in Spain, you can reach out to Applus+ IDIADA for battery testing. They offer SOH checks through their EV engineering and testing services.

► How to get battery SOH in Germany?

DEKRA and TÜV SÜD provide EV battery health reports in some locations.

► How to get battery SOH in Italy?

Italian customers can get their battery health certificate with Quattroruote Professional.

► How to get battery SOH in the Netherlands?

You can reach out to Autocraft EV Solutions, an international company with a facility in the Netherlands that offers SOH testing and other EV battery services.

► How to get battery SOH in other EU countries?

The country you’re operating in isn’t on the list? No problem! These Europe-based providers will ship you the hardware so that you can conduct the test yourself.

Battery state of health - FAQ

What is the optimal SOC for electric vehicles?

You can extend your battery’s life by keeping the SOC between 20% and 80% for daily use. Charging to 100% is fine for long trips but not needed every day.

What is the meaning of SOC for EVs?

SOC means state of charge. It shows you how full the battery is right now.

What is the meaning of SOH for EVs?

SOH means state of health. It tells you how much capacity the battery has left compared to when it was new.

Should you charge your EV to 100%?

You should avoid charging your EV to 100%. Frequent 100% charges can speed up battery wear. For normal use, it’s better to stop at around 80%.

Is it difficult to do the SOH test yourself?

Doing the SOH is easy and requires no training. Just plug the diagnostic tool into the car’s OBD2 port, follow the app instructions, and you’ll get the certificate by email.