DC High Power Logger on the Cheap

I've done a measurement on an almost full battery pack. This charge is from 96% to full. It worked nicely as shown in the plots below. I've now installed it with the fishermen that uses the charger and will return to collect the data after a week or so. The power and energy is calculated from the measured current and voltage. The noise on the current is from me putting zip ties on and fiddling with the Arduino while measuring.