Thank you for your feedback on the 80V 21" Self-Propelled Mower (SKU 2550402 / MO80L416). Based on your description, it sounds like the conditions, heavy overgrowth, uneven terrain, and thick weeds, were beyond what a single-pass cut is typically designed to handle, which can lead to higher battery draw and reduced self-propel performance. For best results in these environments, we recommend first clearing the area to reduce overall vegetation height, then mowing in stages rather than attempting a full cut in one pass, starting at a higher deck setting and gradually lowering it on subsequent passes to avoid overloading the blade and drive system. Slowing your forward pace and ensuring the underside of the deck is clear of built-up debris can also help improve airflow and cutting efficiency, especially in dense growth. In very rough or uneven lots, breaking the area into smaller sections and avoiding wet or matted weeds will further reduce strain on the battery. For additional guidance, Greenworks Tools also offers an official instructional video on mowing overgrown grass conditions, which demonstrates best practices for tackling challenging terrain and maximizing runtime. We hope you will find this information helpful. If you require any additional support or have questions regarding a product, we recommend trying our Q&A section on products' page or Chat with us direct on our website or call 1-888-909-6757. We are here to help.