Exploring the Charging Characteristics of My Solterra EV: My 'Cool Gating' Theory

 Introduction:

In my quest to better understand the charging characteristics of my Solterra, I recently came across an intriguing phenomenon I'm calling 'cool gating.' This would be a more subtle limitation to charging than the 'cold gating'. Through careful analysis of charging sessions from my road trip, I hypothesized that if the minimum battery temperature falls below a certain threshold, the early phases of charging may be limited.

Unveiling 'Cool Gating':

During my charging sessions, I noticed that certain sessions exhibited a limited charging speed during the early phases. This led me to investigate further and theorize that 'cool gating' might be at play. 'Cool gating' refers to a limitation in charging speed when the minimum battery temperature falls below a specific threshold.

Example of normal charging

Example of cool gating

Refining the Threshold:

By reviewing the charging sessions from my road trip, I visually identified which sessions appeared to be 'cool gated.' While I have not yet pinpointed the exact threshold, my initial analysis suggests that it lies somewhere between 22.65°C and 27.24°C. To refine this estimate, I recognize the need to collect additional charging data to gain a more precise understanding of when this limitation occurs.

Collecting Additional Data:

To further refine my understanding of 'cool gating' and establish a robust threshold, I will continue collecting charging data from various conditions and temperatures. This data will enable me to precisely determine the threshold at which 'cool gating' occurs and devise the most effective preconditioning strategy.

My First Tesla Charger Experience: A Positive Encounter with Some Room for Improvement

Arriving at the Tesla Charger:

The location was easily identifiable, and I was relieved to find an available charging spot. However, I soon encountered a minor inconvenience—the charging cable was a bit short. I had to maneuver my vehicle carefully, pulling in extremely close to the parking bollards. In hindsight, I realized there was a parallel charging station nearby that would have offered easier access. It was a lesson learned for future visits.

The Charging Process:

To start the charging process, I signed up in the Tesla app and added my credit card details for payment. I appreciated the convenience of handling the entire transaction through the app. Releasing the adapter and connecting my vehicle for charging was straightforward and hassle-free. Fortunately, I encountered no issues during the charging itself, and my vehicle replenished its battery efficiently.

Post-Charging Analysis:

After completing the charging session, I eagerly sought to review the charging data. Unfortunately, I found the information provided by the Tesla station and app to be somewhat limited compared to other vendors I had tried on my trip. The available data, such as energy delivered, peak power, and session duration, left me desiring more comprehensive insights.

 

Cost Considerations:

One aspect that caught my attention was the pricing of the Tesla charging station. It was slightly more expensive compared to other available vendors I encountered during my trip. While this may not be a significant deterrent for occasional use, it does prompt me to explore alternative charging options when other choices are available.

Conclusion:

My first experience with a Tesla charger left me with mixed impressions. While I appreciated the convenience of the Tesla app and the smooth charging process, the limited feedback and data availability were notable drawbacks for a data nerd. Additionally, the pricing was higher than other available vendors. Consequently, I anticipate exploring alternative charging options unless Tesla stations are the only viable choice in a given area. Nonetheless, this experience has encouraged me to further explore the charging infrastructure and seek out the best options for my electric vehicle journeys.

Remember, your personal experiences may differ from mine, and it's important to consider various factors such as availability, cost, and convenience when choosing a charging station. Happy travels and charging!

Exploring the Charging Characteristics of My Solterra EV: A Road Trip Adventure

 

Introduction:

Last weekend, I embarked on an exciting road trip with my Solterra electric vehicle (EV). Throughout the journey, I kept a close eye on the charging process and collected valuable data to better understand the charging characteristics of my EV. In this blog post, I'll share my observations and present a charging curve chart that represents the estimated charging behavior of my Solterra. Additionally, I'll discuss some limitations I encountered during the constant voltage phase and my hypothesis of "cool gating." Let's delve into the details!

Understanding the Charging Curve:

To analyze the charging behavior of my Solterra, I constructed a charging curve chart based on my road trip data. The chart showcases the relationship between the state of charge (SoC) and battery charging power (y-axis). The orange line represents the charging curve under ideal conditions, assuming an optimal temperature range and a charging station capable of supplying the required current.

Ideal Charging Curve:

According to the ideal charging curve, the charging process follows three primary phases. Initially, the constant current (CC) phase allows for rapid charging, maintaining a steady charging current until reaching approximately 17% SoC. Subsequently, the constant voltage (CV) phase begins, during which the charging voltage remains constant, and the charging current gradually declines. This phase continues until approximately 47% SoC. Finally, the taper charging phase initiates, where the charging rate significantly slows down as the battery nears its maximum capacity.

Yellow Line: Cool Gating:

During my first charges of the day, I noticed a limitation in the charging process, specifically during the constant voltage phase. To represent this limitation on the chart, I plotted a yellow line, suggesting the occurrence of "cool gating." Although further data is needed to confirm this hypothesis, I suspect that battery temperature might be a contributing factor. "Cool gating" appears to restrict the charging speed during the constant voltage phase, potentially as a protective measure for the battery. I plan to gather more data to gain a deeper understanding of this phenomenon.

Gray Line: Two-per-Day DC Fast Charge Limit:

On my road trip, I encountered a charging limit twice, indicated by the gray line on the chart. This limitation seemed to come into effect when the state of charge was above 40%. However, it's important to note that Toyota is actively addressing this limitation. In a recent software release that is currently being distributed, Toyota plans to increase the two-per-day DC fast charge limit to approximately four per day. This update will provide Solterra owners with greater flexibility and convenience during their charging sessions.

Future Blog Posts:

In the coming blog posts, I will share detailed charging session data, overlaying the actual charging sessions onto the charging curve chart. By doing so, I hope to present a comprehensive analysis of my Solterra's charging behavior and shed light on the real-world charging experiences encountered during my road trip.

Contributing to the Knowledge Base:

For fellow Solterra or bZ4X owners interested in collecting charging data with Torque Pro, I am offering instructions and the necessary PIDs (parameter IDs) to aid in building a collective knowledge base for this family of vehicles. By collaboratively collecting and analyzing charging data, we can enhance our understanding of the Solterra's charging characteristics and help optimize the EV ownership experience.

Conclusion:

My recent road trip with the Solterra provided valuable insights into the charging characteristics of my EV. By plotting a charging curve chart and identifying limitations such as "cool gating" and the two-per-day DC fast charge limit, I am gaining a deeper understanding of how my Solterra charges under different conditions.