Daylight drive is the best way to power heavy loads in a DC Microgrid. In daylight drive systems, we wire PV panels directly to DC loads, with no batteries, inverters or charge controller. Because daylight drive appliances only run when the sun is shining, work must be done during the day, or alternative energy storage (like thermal storage, or pressurized water) must be used to provide services at night and during cloudy spells.
Because voltage and wiring requirements are different for heavy loads, a daylight drive system must be wired separately from an Iron Sun box.
Some DC appliances suitable for daylight drive are available on the market, such as DC pumps and Sundanzer refrigerators, that do not require any altering or external switches. Sundanzers use thermal storage to stay cool at night and during cloudy spells. Daylight drive DC pumps are perfectly suited to run irrigation systems during the day. They can also be used to charge pressure tanks or a gravity powered system for domestic water supply.
Another way to use daylight drive is to power an industrial DC motor connected to belt drive equipment, like old fashioned shop tools and tractor implements.
Generally speaking, conventional AC appliances cannot run daylight drive, but there are a few exceptions. These include resistive loads and universal motors. Resistive loads- those that make heat, like hot plates for cooking- will run daylight drive, but take the full capacity of the system, and do not run well in anything less than full sun conditions. It’s important to note that external switches must be installed to run these appliances with DC. DC current will melt switches designed for AC.