This will be several post, the first will show the results. Subsequent posts will show the equipment used and setup.
Conclusions will be the last post.
Parallel connection result;
Maximum observed parallel input to the Elite 100 v2 was 160W.
Series connection result;
Maximum observed series input to the Elite 100 v2 was 206W.
Items used for this demonstration/test;
1. Elite 100 v2 with its MC4 to XT60 solar cable (SOC 78 to 79%)
2. Solar Mats - 2 x 120W solar blankets, one is 5 years old, the other 1 year old.
3. DC power meter.
4. Anderson Adaptor to MC4
5. Two Anderson doubler cables, one wired in parallel, the other in series.
Parallel
Series
NOTES
During this testing there was occasional cloud, however observed results were noted in full sun. It is a month into Spring here in Australia. Ambient temperature was approx 21-22C.
The panels were placed on the roof/bonnet (hood) of my 4x4, such that half of each solar mat was angled and the other half relatively horizontal, to give them a reasonably equal output oportunity.
The solar mat combined maximum output is 240W regardless of connection type.
CONCLUSIONS
When connected in parallel the output voltage is below 20VDC and the amperage approx 10A. As this is below the voltage required to get full amperage input and the higher amperage/lower voltage will cause a gigher voltage drop, the noted 160W output is only 67% of the rated maximum. (I forgot to photograph the power meter)
When connected in series, the output voltage is approx 37VDC and above the voltage required for full amperage input. As the output amps are half that of parallel connection, there will be less voltage drop. The noted 206W output is 86% of the rated maximum and nearly 30% better than parallel connection.
These solar blankets are average quality panels and given the time of year, age mismatch and less than ideal angle to the sun, I am very happy with the output in series connection. You might note, the Elite 100 display shows approx 1.2 hours to top up the 20% required to fill the batteries.
Bottom line - without exceeding the power stations maximum DC input voltage, get the solar output voltage as high as possible to maximise charge rate using Series connection.
This logic applies to most power stations, check your input statistics before applying.