Some info re Solar – I have 4 panels as shown in the picture below. Two are Hardkorr 150W solar matts (Left of pic.) and, although smaller in profile, two Dune 160W folding panels. (right of pic.)
Each of the 2 arrays is connected in Series to a pair of Anderson plugs under the floor of the caravan. Each of those Anderson plugs is wired individually to one of two Victron 100/20 solar controllers.
Here are the panel statistics; (Note - These are brands available in Australia, however, the logic is world wide.)
Victron Stats.
Of note above is the significantly higher Voc and Vmp of the Dune panels. At the time of taking the picture, I opened the Victron Connect App to monitor input to the caravan’s 2 x 100Ah LFP batteries. There is also a Victron Smart Shunt in the system, it and the 2 x 100/20 Solar Controllers are set up in a V.E. network. Both MPPT controllers have the same settings. (At the time the default LFP Victron settings)
These are the noted ouput figures of the two arrays;
There is only a 20W difference in panel rated output or, the hardkorr panels are 6.25% less in rated yield. However, the Dune panels noted a 16.4% higher output relative to rated output. All 4 panels were in the same environment, angled to the sun and had been set up for some time.
Although this test was when connected to my caravan house batteries, I can unplug them from the van, then adjust to connect them in a 2P2S array to my Elite 100V2 for up to 620W input.
Due to the marked difference in output, I have purchased 2 more Dune panels to balance everything regardless of 2S, 2P or 2P2S connection or what they charge. The Hardkorr are retired to my home shed for power station charging in a grid out.
One point to emphasise - A Victron controller needs battery voltage + 5V to work effectively. If charging LFP at around 13.8V in Bulk, this = a minimum 18.8V of solar input. Therefore the Hardkorr Vmp of 18V is not enough when using a single panel.
The Dune’s Vmp of 20.8 is high enough for single panel use. However, with the 100V limit of the Victron or indeed the higher 58 or 60V of a mid range power station such as the Elite 100 or 200, connecting 2 nominal 12V panels in Series is always a better option. Another is to use a nominal 24V panel with a Voc in the high 40V range.
Also of note - the Victron 100/20 has a maximum 290W panel input when charging a 12V battery array. The Dune is 30W higher (approx 10%) and overpanelled. The MPPT will absorb this and rarely in the real world will a panel achieve its rated output.
It is Approaching Winter here in Australia, lower sun angles etc. But I did see a total of 39A charge, in good sun, from both controllers at the Smart Shunt, which included a small 1-2A load on the system.
This setup shows a multi purpose solar array for charging multiple power station and or a caravan. One panel alone will charge my AC2A, Two in Series will charge my AC70 or Elite 100 and all 4 in 2P2S will charge the Elite 100. I run one short splitter cable between 2 panels wired in Series, then the longer 5M cable to the Anderson caravan input to minimise cable length.