Ordered the vest for work having 8 hours out in cold weather. Battery was not sufficient and was out of power in ≈ 4.5 hours. It was a cold day with layered clothing. Ordered a second battery and when it came it would not power the vest. Contacted customer service and having to track down the purchase order number for the vest for them they sent out a new battery which powers the vest. Can now use it for full shift.