Battery discharge at night?

[davo0510]

My question is, can the batteries discharge power through the solar panels at night? My current setup is the Harbor Freight cheapies, 4 panels for supposedly 100W. They are intended for occasional camping trips to charge the cell phone, run a blender or lights. I intend to keep them set up indefinitely and run a small air compressor for a pond aeration 24/7. I’m just wondering if nighttime discharge is an issue and whether or not I need to install a diode to keep this from happening. Thank you in advance for any answers!

[davidcheok]

Energy gets used up when you apply a load. There is no load from PV modules. Loads are anything that changes the electrical energy to other forms of energy that will be used up or dissipated.

[davo0510]

Thank you for your response. The main reason I asked the question was that one of the test questions for upgrading a ham radio license was for this issue. Why do you want to put a diode in a solar system? Maybe today’s panels have that built in. I’m just starting to dip my toe into this to get electric power into a detached garage to run some lights and power tools as well as a pond aeration system.

[davidcheok]

Most solar panels thess days incorporate diodes as part of the design to optimise power output when affected by either shading or cell inefficiencies. These are generally within the module (panel) itself. Most panels have 3 diodes separating the typical three columns and work by bypassing each column when output current is restricted from a cell within that column. Thats for the cell.
Not sure if it makes any sense for a diode within the system itself outside of the panel. Maybe as a power optimiser to control output as part of a system working in the same way as in the panel but to bypass panels completely.

[SunEagle]

My question is, can the batteries discharge power through the solar panels at night? My current setup is the Harbor Freight cheapies, 4 panels for supposedly 100W. They are intended for occasional camping trips to charge the cell phone, run a blender or lights. I intend to keep them set up indefinitely and run a small air compressor for a pond aeration 24/7. I’m just wondering if nighttime discharge is an issue and whether or not I need to install a diode to keep this from happening. Thank you in advance for any answers!

Unless you have loads on the batteries I will say that panels are not loads and should not drain the batteries. What some people forget is that an inverter is a load even when no load connected to it while it is on. Some inverters will use about 1/10th the wattage it is rated for just being turned on. That will drain a battery system.