Hi, I'm damned well amazed at them so far. I mean, I haven't completely flattened them at all, only limiting to 30% and calling that my 'fuel empty'. These batteries need a bit of short trip breaking in before regular use, just to get the electrolytes moving happily; they charge up real quick after only a short trip of a few miles, take a bit longer of course for longer trips. I guess I'm amazed that they still have the grunt when you need it and they haven't bulged at all. I have a friend who has an EV Capri and his car was at the panel beaters and they flattened the pack completely, driving it around and not telling him. XXXXXX gave me one of his dead thunderskys and it was a bit bulged (caused by swelling when the electrolyte in the lithium lattice is not binding). I was able to gently massage it up to charge slowly with a few charging sessions in my lab, so contrary to what some say, the batteries have a bit of staying power. I think Thundersky have lifted their standards a bit from the early days when there was a high failure rate. The BMS has certainly helped to preserve them. Hope this helps.