Why a battery certificate matters, and how to add one to your listing

The battery is the car

On a used petrol car, buyers look at the mileage, the service book and the year. On a used electric car, one number says more than all three: the State of Health of the battery, or SoH.

SoH compares the energy the battery can hold today with what it held when it was new. A car at 92% has lost 8% of its capacity, and with it about 8% of its range. Two cars of the same model, year and mileage can sit several points apart, because fast charging habits, climate and how the car was parked all leave their mark.

The battery is also the most expensive part of the car to replace. So the SoH is the first thing an informed buyer asks about.

A number is not proof

Every listing on evshake states the battery's State of Health. That is already more than most marketplaces ask for. But a number typed into a form is still a claim, and a buyer has no way to tell a careful seller from an optimistic one.

A battery certificate closes that gap. It is a report from an independent test such as Aviloo, or from a garage that read the battery out with the manufacturer's diagnostic tools. It records the measured SoH, the date and the car it belongs to.

What it does for sellers

• Your listing stands out. A confirmed certificate puts the "Certified SoH ✓" mark on your listing.
• Buyers find you. The search has a "SoH certified" filter. Buyers who use it only see listings with a confirmed certificate.
• Fewer questions, less haggling. The most common question is answered before anyone writes to you, and a checked number is harder to argue down.

What it does for buyers

• You can compare cars fairly. A certified 90% and a certified 86% are measured figures, not two opinions.
• You know someone looked. "Certified" on evshake means that we opened the certificate and compared it with the SoH in the listing. Sellers cannot tick it themselves.
• You still check for yourself. On the test drive, ask to see the battery health on the car's own screen as well.

How to upload your certificate

1. Create your listing, or open one you already have, and save it.
2. In the listing form, go to Battery certificate and choose Upload certificate. One file: PDF, JPEG, PNG or WebP, up to 10 MB.
3. We check the certificate against the State of Health you entered and email you the result.
4. Once it is confirmed, your listing shows the battery health as certified.

If we cannot accept a certificate, we tell you why and you can upload another one. Your listing stays online in the meantime. If you later change the State of Health or replace the file, we check it again.

Who sees the file

Only you and the evshake team can open your certificate. Buyers see the certified mark, never the document. If a buyer wants the full report, they can ask you for it directly.

Don't have one yet?

Ask your garage for a battery report at the next service, or book an independent battery test. It costs little compared with what it adds to a buyer's confidence, and it stays useful to you as the owner too.

Selling an electric car? List it on evshake for free and add your certificate.