It’s been raining quite heavily for 2 days, and this evening the battery was down to only 3% state-of-charge. The lights in most of the house run off-grid from the battery, and so I needed to get them some non-battery power. Luckily I’ve recently connected the grid input to my inverter. It was time to test the “bypass” mode where the inverter feeds grid power through to the loads.

It works beautifully, and interestingly in bypass mode the inverter seems to provide a charging trickle of about 1A to the battery even when configured not to charge the battery from the grid. After 10pm when my electricity switches over to cheap off-peak rates I got to test one more inverter capability for the first time: grid charging of the battery! With numerous packs now in my battery build I was able to configure the utility charging current up to the max setting of 60A. This means charging at about 1.7 kW.

The wet and cloudy weather is forecast to hang around for a few more days at least. This grid charging feature means that I can play the merry game of electricity arbitrage: store up cheap off-peak electricity from the grid to use later during expensive peak-pricing times. It’s not quite as good as my own free off-grid solar, but it’s still a way to save money – as well as helpfully “load shifting” to make the grid run more smoothly.