We are inviting our community of citizen scientists to participate in a voluntary experiment to understand more about how temperature affects EV charging.
Starting this month, as many of us across the US experience the harshest weeks of winter, we want to compare how much cold weather decreases charge efficiency at different temperatures in different regions.
Data will be aggregated anonymously and published for the EV community on this URL. The experiment is open to all EV makes and models that are Level 2 or DC Fast Charge compatible. Unfortunately, we are not currently investigating Level 1 charging right now.
To be eligible for this experiment, we ask that your beginning state of charge be at least 20% and that you charge no higher than 85%. This prevents charge tapering or voltage restrictions at the extreme ends of the battery capacity. If your vehicle shows state of charge in terms of capacity bars, that is fine – please simply note the starting and ending numbers of bars, including partials (Ex. 9.25/10 or 15.5/20).
In the experiment survey form, only the temperature is required, but as much data as possible is helpful. Here are the fields in the form.
- Email address in case we have follow up questions – this is not shared or added to any mailing lists!
- Start and stop time (or duration of charge) minus any idle or non-charging time.
- Beginning and ending range estimate (in miles; for Bolt EVs, use the middle estimate)
- Beginning and ending state of charge (in %, kWh, or bars)
- The outdoor temperature. If your vehicle is charged inside or in a location with climate control, just let us know the indoor temperature.
- Charger speed, brand, or other details (if known)
- kWh consumed (if known) as read by the charger, not by your battery
Final things to keep in mind:
- You can contribute to this experiment multiple times, presumably in different weather conditions.
- Please make sure not to change your climate control or auxiliary system settings between the initial and final range readings.
- Please log temperature in Fahrenheit and distance in miles for consistency.
Does that all sound interesting?
What’s in it for you?
Science! The main draw of this experiment is advancing the EV community’s understanding and accuracy of real-world battery charging in different conditions. But, as an additional thanks for sharing your time, we will give you first access to our findings and will also send you a Recurrent charging sign (pictured above!) for people in the US who want one. If you do, simply follow the link that is presented after submitting the experiment form.
Please note that participation in this experiment is totally voluntary. This should be no different than a normal charge – we just need your help collecting this data to help accelerate EV education and adoption. As always, we do not share your individual data with anyone and we aggregate and anonymize all data before using it.
If you have any questions, please email us at firstname.lastname@example.org and we’ll respond as quickly as we can!