# Donut Lab Solid State Battery Test 4 - Shocking! Source: https://www.youtube.com/watch?v=5cpYeT4VmSY Recap page: https://rapidrecap.app/video/5cpYeT4VmSY Generated: 2026-03-17T04:51:09.721+00:00 --- ## Quick Overview The Donut Lab's subsequent tests confirmed that the liquid-cooled 120 kWh battery pack in the Lucid Gravity is capable of maintaining a high charge rate (peaking around 375 kW) up to 70% State of Charge (SOC), significantly outperforming the air-cooled Version 1 test, which required a major taper around 50% SOC due to thermal limitations. **Key Points:** - The liquid-cooled Lucid Gravity battery pack maintained a peak charge rate near 375 kW up to 70% SOC, demonstrating superior thermal management compared to the air-cooled version's taper around 50% SOC. - The air-cooled battery (Test 1) showed a significant charge rate drop around 50% SOC, hitting a low plateau before recovering slightly, while the liquid-cooled simulation (Simulation 2) maintained a high rate until approximately 75% SOC. - Simulations indicated that a 120 kWh pack with the liquid cooling could charge from 0% to 80% in about 18 minutes, significantly faster than the 26 minutes estimated for the air-cooled pack. - Comment analysis revealed the top recurring themes included demands to weigh the battery for density proof, skepticism about unverified 300k cycle life claims, and comparisons to BYD/Chinese vehicles. - The VTT lab test on a single cell showed that charging at 11C (the claimed rate) generates 121 times more thermal stress than 1C charging, explaining the necessity for advanced cooling. - The air-cooled motorcycle battery test showed a sustained charge rate around 100 kW until about 60% SOC before tapering down, whereas the liquid-cooled simulation maintained a much higher rate across the entire curve. - The audience strongly desires real-world testing (e.g., by Bjorn Nyland) and wants to see the technology scaled to cars and e-bikes, not just motorcycles. ![Screenshot at 1:13: The C-Rate vs State of Charge graph clearly illustrates the massive performance gap: the liquid-cooled \(orange\) curve maintains a high charge rate \(around 5.5C\) until nearly 50% SOC before tapering, while the air-cooled \(blue\) curve drops significantly sooner.](https://ss.rapidrecap.app/screens/5cpYeT4VmSY/00-01-13.jpg) **Context:** This video follows up on previous testing of a solid-state battery pack technology developed by Donut Lab, focusing specifically on the thermal management capabilities of a large, liquid-cooled 120 kWh pack simulation compared to an air-cooled version tested on a motorcycle. The creator analyzes real-world charging data from the motorcycle test and compares it against simulations for the larger EV battery pack, addressing audience skepticism and comparing the performance against competitors like Lucid and BYD. ## Detailed Analysis The video compares the charging performance of an air-cooled battery pack (tested on a motorcycle) against a simulated liquid-cooled version of the same chemistry scaled up to a 120 kWh car battery pack. The initial motorcycle test (Test 1) showed the air-cooled pack hitting a thermal limit around 50% State of Charge (SOC), forcing a sharp reduction in charge rate, holding a low plateau until about 80% SOC. The simulation (Simulation 2, representing liquid cooling) demonstrated dramatically better performance, sustaining a near-peak charge rate of 375 kW all the way up to 70% SOC before a steep taper began, indicating that liquid cooling is essential for utilizing the high C-rate chemistry of the solid-state cells. Calculations based on the simulations showed that the liquid-cooled pack could charge from 0% to 80% in about 12 minutes, saving 14 minutes compared to the air-cooled pack's 26 minutes in the same range. Furthermore, the superior thermal capacity of the liquid-cooled pack allowed it to maintain a 3.2C charge rate up to 45% SOC, whereas the air-cooled pack was limited to 1C. The thermal necessity is underscored by the equation HEAT = I²R, showing that doubling the current quadruples the heat generated, meaning 5C charging produces 25 times the heat of 1C charging, and 11C (claimed) produces 121 times the heat. The analysis of audience comments highlighted major recurring themes: over 30 comments demanded proof by weighing the battery for energy density claims; over 20 comments requested cycle life data; and others questioned why VTT testing hadn't been done, compared the tech to BYD, or expressed a desire to see the technology applied to cars and e-bikes rather than just motorcycles. ### Motorcycle Charging Test (Air-Cooled) - Initial charge rate peaked around 103 kW, maintained until about 60% SOC before tapering down, hitting a low plateau after 70% SOC. ### Car Simulation (Liquid-Cooled) - The 120 kWh pack maintained 375 kW peak charge rate until 70% SOC, resulting in a 0-80% charge time of approximately 18 minutes, compared to 26 minutes for the air-cooled counterpart. ### Thermal Physics Explained - Heat generated scales with the square of the current (I²R); 5C charging generates 25x the heat of 1C, meaning liquid cooling is mandatory for high C-rates. ### Audience Sentiment Analysis - Top themes included demands for battery weight verification (30+ comments), skepticism over 300k cycle life claims (20+ comments), and interest in applying the tech to cars/e-bikes (10+ comments). ### Addressing Skepticism on 11C Claim - The presenter notes that 11C is a cell-level lab capability; the air-cooled production motorcycle was limited to ~5C peak, and the liquid-cooled simulation showed a peak of 5.72C. ![Screenshot at 00:00: A green electric motorcycle is shown connected to a charging station with the charge status indicating 9% charge and 16 kW power input.](https://ss.rapidrecap.app/screens/5cpYeT4VmSY/00-00-00.jpg) ![Screenshot at 00:13: The presenter introduces the comparison by stating that the data allows drawing lines and seeing how remarkable the battery is.](https://ss.rapidrecap.app/screens/5cpYeT4VmSY/00-00-13.jpg) ![Screenshot at 01:13: A graph titled 'C-Rate vs State of Charge' plots the charging rate \(C-Rate\) against the State of Charge \(%\), showing the superior orange line \(Donut\) maintaining a high rate compared to the lower blue line \(Lucid\) until around 80% SOC.](https://ss.rapidrecap.app/screens/5cpYeT4VmSY/00-01-13.jpg) ![Screenshot at 07:23: A graphic illustrating the thermal impact of high C-rates: 1C yields 1 unit of heat, while 5C yields 25x harder thermal stress \(5² = 25\), emphasizing the need for cooling.](https://ss.rapidrecap.app/screens/5cpYeT4VmSY/00-07-23.jpg)