Are DualSun panels equipped with bypass diodes?
Yes ! Each DualSun panel is composed of cells, which are divided into several strings separated by bypass diodes.
The number of strings is different according to the technologie (Half-Cut or Shingle)
All the cells of a string are connected in series and thus the cell that produces the least sets the current of the whole cell group. Thus if one cell of string A is shaded at 100% and thus has a current of 0 A, none of the string A cells will produce electricity either. However, string B and C will not be affected.
To explain better, here are some measurements on a string of FLASH 375 Half-Cut Black connected in series on a string inverter.
Shade | Imp (A) | Vmp2 (V) | Vtot (V) | Inverter power (W) |
None | 7.4 | 30 | 144 | 1000 |
Partial shadow of one panel only | 7.2 | 20 | 134 | 960 |
Total shadow of one panel | 7.3 | 1.2 | 110 | 800 |
We can see that the shade on a panel does not reduce the production of all the string to 0 but only has an impact on the delivered power of the group.
To illustrate how the diodes work, here is a diagram showing the wiring of the diodes and cells for three panels connected in series. A panel consists of three strings of cells represented by circles. Each string is associated with a diode in parallel.
When the 3rd string of the second panel is shaded , voltage Vp2c3 at the terminal of the cells becomes lower than Vcutoff of the diode. The diode then let the current Imp Pass. The current of the panel series remains the same, only the voltage decreases.
> To go further : How are the by-pass diodes positioned in the DualSun Shingle panels?
