Hi, I bought a house that contains an off grid Victron installation.
The installation contains a Blue Solar 150V/70A charger.
3 77W light bulbs are installed in parallel to the PV input of the solar charger.
What is the reason for these light bulbs? Are they really required?
Kind regards,
Bart
If they actually light up, could just be the installer needed to know when the solar power was active. But you are losing 3x 77W of solar if they do.
A more interesting explanation could be that the series Voc of the string of panels exceeds 150V when cold, and they wanted to prevent the Blue Solar from blowing up by reducing the total voltage. But that’s a horrible way to do it.
If you can determine the VoC of the panels (on the label?) and how they are wired you can check this.
They light up and the brightness changes continuously.
The Voc of the string is 154,4V calculated with the Panel Voc given in the datasheet. So this is not even at low temperature.
Is there another way to protect the Blue Solar that doesn’t waste so much power?
Reconfigure panels from series to parallel or combination of.
For example if panels are currently 3S2P , could change this to 2S3P, this would lower overall VOC by 1/3.
That is not really a solution.
For the moment the configuration is 4S2P, but the orientation of the 2 strings is completely opposite.
Only configuration that is still possible is 2S4P.
If it is not possible to reconfigure panel wiring, then the only other solution is a higher voltage MPPT
Consider buying a second controller, could be another 150/70 and then put each of your opposite facing panels on their own controller in a 2S2P configuration.
With panels in opposite directions you will never get both sets of panels working at peak power. Mine are east and west facing and have 2 controllers. By adding a second controller you remove the loss to the light bulbs but also improve the system performance as a whole.
Your system sounds like it was done to a tight budget by the previous owner.