Table of Contents

My solar isn't charging

Reminder: a solar charge controller makes power

  1. when power is demanded for charging or loads
  2. up to its abilities under present conditions

In most cases the system is working as designed but the owner doesn't know it.

because no power is being demanded

If no power is demanded then no power is produced. This can happen when

charge-and-stop

Charge-and-stop usually charges to 14.2v or 14.4v then stops until nank voltage drops to 13.2v before restarting Bulk charging. This occurs because charge-and-stop does not use a Float setpoint.1)

Under very light loads this would result in cycling between 90% and 100% state of charge. Because of voltage sag heavy loads might result in cycling between 95% - 100%.

If this is undesirable behavior you can set up a USER profile with whatever setpoints you wish (suggested settings).

because the panels aren't receiving full sunlight

because the BMS has shut down charging

…because of temperature extremes of excessive charging voltage. (lithium only)

because something has actually gone wrong

It's rare, but sometimes things happen. Fuses pop. Branches reach under and disconnect solar cables Parts fail.

further reading

1)
Li doesn't need Floating in the lead-acid sense, but it can still be useful.