evaluating Voc and Isc???

[tayfuny]

hi guys,
i searched that topic but couldnt find. as i said im a wannabe at solar energy,if u can help me, i ll be grateful.

i got 2 different solar panels. There are some values, but i cant evaluate them. I know the meanings, but what they refer to me, and how can i evaluate panels with these values, i have no idea :/

1 of them is 30W, max power voltage: 17.2V,max power current: 1.75A, Voc:21.6V, Isc: 1.90A
2nd; 20W , max power voltage:17.3V, max power current:1.16A, Voc:21.8V, Isc: 1.30A

how can i read them as efficiency, produce capacity etc..


thank u for ur answers

[SunEagle]

hi guys,
i searched that topic but couldnt find. as i said im a wannabe at solar energy,if u can help me, i ll be grateful.

i got 2 different solar panels. There are some values, but i cant evaluate them. I know the meanings, but what they refer to me, and how can i evaluate panels with these values, i have no idea :/

1 of them is 30W, max power voltage: 17.2V,max power current: 1.75A, Voc:21.6V, Isc: 1.90A
2nd; 20W , max power voltage:17.3V, max power current:1.16A, Voc:21.8V, Isc: 1.30A

how can i read them as efficiency, produce capacity etc..


thank u for ur answers

The panel wattage rating is calculated by the max voltage x the max power (amps).

The Voc is the open circuit voltage which is what the panel can put out when not connected to any load.

The Isc is the short circuit current which is used to determine the size fuse to protect the panel from a short circuit.

Panel number 1. 17.2volts x 1.75amp = 30 watts.

Panel number 2. 17.3volts x 1.16amp = 20 watts.

The efficiency of the panel is usually shown as some percentage of watts per square meter. Mono crystalline are usually more efficient then poly crystalline or thin film type panels.

Hope that helps you.

[tayfuny]

The panel wattage rating is calculated by the max voltage x the max power (amps).

The Voc is the open circuit voltage which is what the panel can put out when not connected to any load.

The Isc is the short circuit current which is used to determine the size fuse to protect the panel from a short circuit.

Panel number 1. 17.2volts x 1.75amp = 30 watts.

Panel number 2. 17.3volts x 1.16amp = 20 watts.

The efficiency of the panel is usually shown as some percentage of watts per square meter. Mono crystalline are usually more efficient then poly crystalline or thin film type panels.

Hope that helps you.

thank you suneagle, that was helpful about Isc and Voc.
So we must test Voc and Isc with the "given values from producer" to understand if panel is good quality?

[SunEagle]

thank you suneagle, that was helpful about Isc and Voc.
So we must test Voc and Isc with the "given values from producer" to understand if panel is good quality?

Usually each of the "cells" has a very small voltage rating. The more you wire in a series string the higher the total Voc the panel is rated. Usually a mono crystalline cell panel that puts out 17.5 volts has 36 cells and about 4.5 amps which gives it a rating of about 80 watts. Since your panels have the same voltage but lower amps then they are not as efficient.

Since both of the panels you are mentioning have about 17 volts they probably have the same number of "cells". If you have two panels that have the same number of "cells" then the one with the higher amp rating usually is the more efficient.

[Sunking]

You cannot measure Vmp Imp, and Isc as that takes controlled lab conditions. You can measure Voc and get a rough idea of Isc.