Unbalanced Solar Panel String Current

A panel string is a group of panels wired into a single input on your inverter.

Unbalanced solar panel string current. Archive view return to standard view. Ie mppt input voltage x current allows full string power. An sb 6000 has 3 strings of 11 upsolar 225s. The strings of 11 measured 363v while the string of 10 measured 330v.

Now assume one panel in string 2 goes partially shaded to a 0 4 sun level not low enough for bypass diodes to kick in string 1 still operates at pm 2928 w imp 7 86 a vmp 28 66 13 373 v each panel in string 2 is forced to operate at 28 66 v the same as string 1. Thus string 2 current reduces to 3 0 a to stay on each panel s i v curve. You need to understand how different stringing configurations impact the voltage current and power of a solar array. The number of panels a string inverter can handle depends on several factors including the output current and voltage of the panel you are using the number of strings allowed by the inverter the maximum and minimum voltage allowed per string for the inverter and the minimum ambient temperature for your location.

For example this grid tied system contains 24 mission solar 360w panels and one sma sunny boy 7700w inverter. So the system was operating essentially with two strings of 11 and one string of 10. The inverter appropriately called a string inverter has three string inputs. For example if the solar panel is rated at 175 watts and the maximum power voltage vmp is given as 23 6 volts then calculate the current as 175 watts divided by 23 6 volts which is equal to 7.

One upsolar panel needed replacement its output was zero.