Have you ever wanted to get an idea of how long a charge will take? Perhaps you've used the charge rate table from my ancient blog, then added 20% because you're charging at a 208V station instead of 240V, and then added in some extra time because you know the charge rate will taper down as it gets closer to fully charged. Been there, done that. I've wanted to improve that experience, but it took a bunch of time just to do the very simple analysis for that blog and I needed a lot more data. Earlier this year, MarkWJ gifted me with anonymized data collected from over 7000 charging sessions via OVMS from 126 vehicles. That data allowed me to build a much better charging model for the Roadster. The data also shows how much variation there is among charge sessions due to external factors, so the charge time prediction isn't going to be perfect but it seems to be working pretty well. How I developed the charging model and its limitations are explained here: OVMS and the Tesla Roadster Charge Time Predictor The charge time predictor is now built into the latest firmware version for both OVMS and the Tesla Tatter. OVMS now has a new feature (only available in V2 hardware) that lets you set a charge end time, so your car will finish charging close to when you're ready to leave (within the limits of the accuracy of the charge time predictor). It's also better for the grid if EV owners set a change end time instead of a charge start time to avoid the spike from every EV starting to charge when the lowest time-of-use rate kicks in. For Roadster owners who don't have one of the telematics gizmos, I highly recommend you get one, but I've also made the charge time predictor available via a web page: Tesla Roadster Charge Time Predictor You can fill in custom values (charge mode, battery pack capacity, preferred units, typical ambient temperature) and the page will give you the time estimate and also generate a link you can bookmark to load the page later with your values already filled in. The algorithm seems to work pretty well for level 2 charge rates in moderate temperatures. If you're doing 120V charging, especially at 12A and lower, the charge rate is highly variable and more difficult to predict. The predictor doesn't consider starting battery pack temperature, so it doesn't take into account situations where the car is cold enough that the pack needs to be heated before it can charge (I need more data to model that). I also expect it won't do a great job in really hot weather because the values from the ambient temperature sensor on the vehicle are often quite different from the actual air temperature. It also doesn't do anything to model the difference between charging in an open air carport and a small, tightly-enclosed garage. Still, it's better than the old way of estimating charge times. Please give it a whirl. Let me know how it works. If you have a case where it's consistently wrong, send me your data, preferably with the corresponding OVMS server logs.