I have an assortment of panels and solar charger controllers that I do not use. I have a property that is completely off-grid. I have solar power sufficient for what I need.  

I have a 180watt connected to a Victron 75/15  that was used for an electric fence. A 265watt that was connected to a Victron 100/30 for 12v basic lighting and 2x 120watt panels along with a Victron 75/15 for camping power. All of these I do not use anymore.

At my off grid camp I have a staff member. I installed for him another bunch of very old solar connected to a Victron PWM for basic lighting. I want to combine all the panels to provide to this staff member some more power, connected to a 12volt Hubble or Freedom won.

What can I expect from the 4 panels I mentioned above? If I connect all 4 in series on the Victron 100/30 what can I except. Or should I do two strings connected to the 2x Victron 75/15's    

58 minutes ago, Bushkey said:

If I connect all 4 in series on the Victron 100/30 what can I except.

You should avoid connecting four solar panels in series to the Victron 100/30 charge controller, as this would exceed its maximum DC input voltage (Voc) of 100V. Additionally, using mismatched panels in series can reduce efficiency.

The best approach is:

1. Victron 100/30 SCC – Connect two 120W panels in series. This ensures optimal performance within the controller’s voltage range.

2. Victron 75/15 SCC – Connect the 180W panel separately.

3. Another Victron 75/15 SCC – Connect the 265W panel separately.

If you were to connect the 180W and 265W panels in series, the higher-rated 265W panel would be limited by the lower 180W panel, effectively reducing its output to match the smaller panel. This would give a total of only 369W and lead to inefficient MPPT tracking.

By using separate charge controllers for each panel type, you maximize power extraction, yielding 445W (minus the current limit on the 265W panel when connected to the 75/15 SCC at 12V). This setup ensures better efficiency and higher overall energy output.