Jaco Venter wrote: ↑
Tue, 14 May 2019, 02:19
1) THe PV Watts will fall away to 0 W the moment a load is introduced. (Not only for electrical motor loads) The Watts will come back about 30 seconds later.
That sounds very much like the Solar Charge Controller is getting reset. It could be getting reset by the DSP (main processor) via an RST command, or it might be panicking.
2) The Inverter will freeze whereby the PV Watts fall to 0 and it will stay down until the whole system is switched off and on. Then the PV Watts are back again. (It happened twice today)
My wild guess is that after a certain number of panics, the SCC completely switches off to protect itself.
My installation is as follows:
1)15 off 340W AE Solar Panels
That sounds like you have your panels configured as 3S, and those AE panels are 72-cell (from this page
). Voc at 25°C is 46.74 V, quite high, so the total Voc would be approaching 140 V. So you will have quite high PV voltage. With the weather cooling off in the southern hemisphere, the voltage will creep higher. I know nothing about the King/MK Solar Charge Controller, but it has a 145 V max Voc the same as most PIP/Axperts, so I presume it's similar. The Axpert/PIP SCC starts derating (reducing its target power point) above 130 V of panel voltage. You say the problem appears when a load is introduced. Is it possible that it's actually worse when a sizeable load comes off? Then, the SCC will reduce its load on the panels, which will then increase in voltage, and the SCC may panic when the voltage approaches 145 V.
Perhaps you could monitor your PV voltage before and after one of these SCC resets? That should give an indication as to whether PV voltage is likely to be a contributor, or put that theory to rest.
I note that @affer
is also running 3S, probably also 72-cell panels. He's from the northern hemisphere, but from a cold country (Denmark), so while this is a common arrangement, it's something you have in common.
The other thing is that 15 x 340 W = 5100 W, which is possibly too high for the King's SCC to handle. Sure, it only uses what it needs, but the higher the panel power, the quicker it will react to a given change in PWM ratio (how hard the SCC tries to draw power). Voltronic Power SCCs are prone to overshoots at the best of times, so with more PV power than they are designed for, they will likely overshoot and undershoot more frequently. Since you are already near the absolute maximum allowed PV voltage, changes in SCC load could result in undershoots which cause a quick rise in PV voltage, which might cause the SCC to initiate a panic reset.
Is it easy to temporarily turn off a string or two? If so, that would be an easy way to validate or disprove that theory.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, PIP-4048MS inverter, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
160 W solar, 2.5 kWh 24 V battery for lights.
Patching PIP-4048/5048 inverter-chargers.