Ways to Calculate Battery Capacity / Degradation

Featured Image source: InsideEVs

Own a Tesla and want to calculate your remaining battery capacity?

It’s no secret that Tesla’s batteries lose capacity over time, but how much? Well, Tesla states that their batteries only see 12% degradation over 200,000mi (on average) based on their real data from Model X and S. This is great data and Tesla states that they intend on presenting more data relating to battery capacity retention in the future.

Based on some research I’ve done and some feedback on X (formerly Twitter), I’ve gathered several different ways that you can calculate your remaining battery capacity in your Tesla! I will use my 2023 Tesla Model Y for examples.

1. You can manually calculate this figure. At 100% SOC our Model Y currently shows 312 miles of range at over 25,000 miles. When we took delivery, it displayed 330 miles of range. So to calculate

• Battery Capacity = (Current Displayed Range / Original Displayed Range) * Original Battery Capacity = Current Battery Capacity
• My 2023 Model Y Battery Capacity = (312mi / 330mi) * 79.5kWh = 75.16kWh

2. You can check your battery health on the Tessie app (subscription required). To do so, go into the Tessie app, select battery, and press the little heart icon in the top right of this screen.

• The image below shows my Tesla Model Y battery health at about 25,000 miles, 74.8kWh.

3. You test your battery health in your Tesla in Service Mode (see video link below). I started doing this but decided against it as there are risks associated with this I was not willing to take. This test also takes around 24 hours.

• https://www.youtube.com/watch?v=z7rIpqM8zwU

4. Less specifically, you can notateslaapp.com says “You can then tap “Request Service”, choose “Battery & Charging”, and finally “Range”. If you’re prompted to pick a service center, go ahead and pick any service center first. You’ll then be asked to describe the concern. You can type in “range” or any other text and then tap Next at the bottom.

Keep in mind this is an automated solution and your request won’t actually go to a service center when you tap Next. The app will perform a quick self-diagnosis to see if your battery is within the normal range of degradation. This is a quick self-test and just lets you know that you’re well within Tesla’s expected battery degradation levels.

Why is this important? Well if you’re anything like me, you like to do a lot of calculations to maximize your travel efficiency while road tripping with your Tesla! The link below shows a previous blog of mine where I highlight ways to save time and money while doing longer trips in a Tesla. If you’re truly trying to minimize charging time, driving to the lowest (safe) battery percentage possible is essential to maximize your Supercharging curve. To do so, I often also manually calculate what efficiency is required in order to reach our next charging stop or destination.

For example, you’re driving and have 50% battery in my Tesla Model Y referenced earlier. Given my previous calculations, you also have about 75kWh of usable battery capacity. At 50% SOC, you now have 37.5kWh. Say your current efficiency over this trip has been 300kWh, you have about 125 miles or range remaining (37.5kWh / 0.3kWh = 125mi). If your destination is further than that, you need to slow down and work on getting a better efficiency. If your destination is only 100 miles away, you can speed up!

Previous Blog:

How to Most Efficiently Road Trip in a Tesla

I hope you enjoyed this post. This is brought to you by Alan Meyer, owner of the TesCalendar. Please check the TesCalendar our at TesCalendar.com or on X(formerly Twitter) @TesCalendar1.