Any longer than you have to. How many cigars are bad for you? Well, all of them right? But one every once in a while won't kill you. Much.
Something I bet just about nobody does: Use a simulated load to drain the pack back down if you zap up to 100% and then change your plans and bail on your ride. I have two of these I can hook into parallel that create about a 14a peak drain together, or just one for about 7a. Hook it up to a cheapie watt meter and when its back down to 55v or so job done.
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