Connecting devises to solar panel
Some people treat solar panel as a battery with exact or close to exact voltage. Solar panels are made to specific applications with specific voltage parameters and wattage.
“12V" Solar panel can easily output anywhere from 0V to 24V. A few volts would comes out on a dark, hazy day or under shade, made by a tree or simply a near by pole. 24V can be made without much load.
This can be very dramatic for some devises, not meant to run in such vast ranges of voltages.
Situation can be soften by connecting solar panel to a battery. In this case, battery will act as a capacitor. For example: 12v lead acid battery can take anywhere from 12 to 24V and store it chemically as an electric energy inside the battery. In this case, if you take your voltmeter and measure battery voltage, you might see anywhere from 11V to 15V, even though at that moment, the solar panel might try to supply 24V to the battery. You might ask: why battery don't care and my radio, connected to solar panel without controllers or battery dies very fast? This is only because some chemical processes (in the battery) can be robust and won't be damaged by voltage, but most of electronics have components designed to be good up to certain voltage level. Above some threshold, those components will be damaged by high voltage.
Very typical question from most of users:
“I have solar panel XYZ. Can your device ABC work with that?”, OR “I bought ABC....it is not working with my solar panel!”
Buy all the equipment meant to work with such voltages. Start from the end task and work the whole idea through on a paper with understanding of what power you need and what kind of solar panel might fit this task. Then look again at the solar panel characteristics and see if voltage ranges are acceptable by the equipment, you are truing to connect to.
For example the DAC-2424 can work between 20 and 30V. If you have battery connected to solar panel, then it is most likely around 25...26V and that inverter will work fine. But if the battery goes dead or break up connection due to oxidation, then the inverter can be burned by excess of voltage.
Solar controllers meant to solve most of power connections between solar panels, batteries and devises or applianses meant to worth with that power.
To be continued....