How long do the batteries last?

According to the manual only 7 hours, but in our experience the batteries last up to 48 hours (Rechargeable 2500 mAh Duracell). When logging longer periods of time it is recommended to use a USB power supply and connect it to the USB C power supply port on the meter. Alternatively one could also use a large USB power bank, just make sure it is large enough to last the duration you want to log for. A 10 0000 mAh Power bank will last 3 days in our experience.