Hmmm, that's not good. I did one charge to 86% in 39C heat on Monday, with AC on, no power reduction. It was heavy traffic 40-50mph before that so battery had been having an easy time. I have never had a power reduction after charging. Only after a little too much fun, or running the battery low. If I've got the battery fun-soaked, it doesn't take long to recover, maybe a few minutes. I have heard of people getting power reduction after charging. I'm curious to find out why some of us are immune to this, and others aren't. I'm wondering if you have a cooling issue. Perhaps a stuck valve, somewhere?