Why isn't my solar panel charging?

One reason your solar panel might not be charging is a buildup of dirt and dust on it. Give it a quick clean using a damp cloth to improve its performance and allow it to fully charge. Choose a spot with good access to direct sunlight for optimal charging.

Why do solar panels have a low voltage?

The series resistance of the solar cells in a panel could have increased over time. This may be the result of a hotspot that may occur when micro cracks appear in the cells. The result is a lower voltage in the panel, which will bring the overall voltage of the solar array down.

Why does my solar charge controller float?

With 100AH batteries they should be full when the return current drops to 1.5-0.75A at 57.6-60V. If your solar charge controller is dropping to float before this happens, it is going to cost you battery life. Premature float is an endemic problem from my experience. Often the result of poorly designed or programmed solar charge controllers.

How much voltage does a battery show when the sun goes down?

If I look when the sun goes down, say when sun power falls to say 100W, shortly before sunset, when its power is below the load for the first time (say the load is 150W), then the battery is showing about 50.2V. Assuming a roughly linear relationship between voltage and state of charge, that would be about 80%.

Do battery chargers drop voltage?

One last thing to play with is the difference between the voltage output at the charger terminals, and the input at the battery terminals. There could be a slight amount of voltage drop depending on the thickness of your battery cables. One word of caution though.

What was the battery voltage during a sunny day?

100% sunny day. Battery was at 53.0V while charging but not at max state of charge. The current was around 17A, then 11-12A. As the voltage steadily increased to 54.0V over some minutes or an hour or more as it was charged up the current steadily reduced and was as low as 2A.