Michael,
as you have discovered it was no good idea to combine solar panels of different make and size. Each of this panels has it MPP (maximum power point) at a different voltage, so it is nearly impossible to get the maximum out of them. But even you would have identical panels you will not get the maximum specified:
- flat oriented panels with mono/multicrystaline cells will only get a reduced amount of solar energy depending on the angle of the sun.
- every little shadow will reduce to output of a typical panel drastically
- the charge controller has some loss
- the battery may not be low enough to accept the maximum charge current
- the panel are not running in the MPP
- if the temperature is high the output is reduced (typical 20 % on hot days)
I have a few questions:
- What was the state-of-charge of the batteries during the test?
- What was the voltage of the batteries during the test?
- What make of charge controller are you using?
- I this a MPP, Shunt, ... controller?
- What is the highest voltage for charging?
- Does the charger temperature compensation?
- How thick and long is the cabeling from the panels to charge controller?
- How thick and long is the cabeling from the charge controller and the batteries?
First of all I would remove the two smaller panels from the charge controller. If you like to use this two panels you should use a separate charge controller for them in order that the other panels can run at the optimal point.
Check the cabeling and the connections. An ideal system would have equal runs of cable that is thick enough to have less than 0.3 V voltage drop at maximum current.
To test the panels it would be best to measure on a sunny and not to hot day at noon the unloaded voltage and the short curcuit current of each panel separately before the charge controller. But you have to have a ampere meter that can handle the current. Avoid any little shadow on the panels.
If the charge controller as an internal temperature compensation then keep the space around the controller very well ventilated. Otherwise the controller will throttle down the output voltage and current.
Emil