what runs down the battery on a 2020 honda pilot and wont let it start

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. I currently operate a Honda parts and service department and am around these vehicles daily. I've also owned a 2020 Pilot. I can tell you - there is no "common" problem for the concern you are sharing for your Pilot. I truly do not know of any component that will drain the battery - from a pattern failure point of view. Certainly, anything is possible - but on a Honda, it usually isn't. Have you had the battery tested for state of charge and the ability to sustain a load? In many cases, the battery itself is the cause of the problem. If you have a Touring or Elite model, your battery is a AGM Spiral type battery which is different than your typical lead acid battery. This makes it stronger dealing with the auto-stop feature for fuel savings. Special testing is required for an AGM battery. Hands on testing from a shop near you is needed. https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.