2 LV6548s strange behavior when under loads > 60%

2 LV6548s in parallel. When the loads are less than 60% they operate normally. MPPT current on all 4 inputs is right at the max produced by my panels = approx 17-18amps. I'm nowhere near maxing out this system...

But when the load on either inverter goes above about 60% and the sun is shining right above, both MPPT currents oscillate between zero and max. This happens on either inverter, and I've moved loads from one to the other and confirmed the behavior. As soon as loads go under about 60% everything goes back to normail.

I graphed this phenomenon in home assistant, and I'm only showing inverter 1 and one pv input (pv2) below for clarity. The other PV1 current graph is similar. Load % is yellow, current is red.



any ideas? This one has me stumped. The temps are normal. Battery is at 100%. When this occurs, the grid is pulled in as is battery power.

The PV Power graph follows the above current graph. When the current drops, so does pv power (As expected). But why is this happening? I would expect the PV power to stay at max as load increases.


the graph is totally normal during the AM as the sun comes up and batteries are charged, as long as the loads are less than about 60%.

What did your vendor say about it?

sunshine_eggo said:

What did your vendor say about it?

Click to expand...

I asked Ian at Watts247 to take a look at this thread this AM and give me his thoughts.

I reviewed all my settings again this AM and the only thing that stood out was setting 11 - "Maximum utility charging current"
which I had set at 30A so as not to tax the batteries when charging them, assuming this param only affected that function. I just upped it to 50A on both inverters.

I interpret this setting to mean the max current the grid will draw when charging the batteries, but only because the words UTILITY and CHARGING are in the description. However, using that rare "Chinese translation" option, it might be the max current limit on the PV inputs, and this might make sense because when both PV inputs are hitting max, the current is 17.5+17.5=33A and that's when the weirdness is there.

I dunno, it's just a theory right now. We'll see later today.

Here's a graph of current 1&2. When the graphs line up, both inputs are producing max current. It sort of tracks, esp when the load goes up, but not everywhere, esp the circled areas, and that might just be due to the MQTT bus reporting frequency of the parameters or hysteresis of each pv input.

Again, this is all just speculation at this point.

Well, changing that setting #11 had no effect. Same thing is happening today as it was yesterday. Load is around 64%. Interestingly, the graph below shows the oscillation occurring at 13-14amps which is because it was later in the afternoon and sun was going down so not as much power production. So it is directly related to and caused by higher loads on the inverter, apparently not PV current.

No word from Ian yet.

Wow... nobody's seen this before? Im still chasing this problem...

I watched the inverter yesterday and it's showing an error "10" when this happens... which is "PV over current". I don't even know how that's possible. I had 2x the panels on those inputs previously and never got that error - pv current just never got above 17.5 amps.

It was wired 3S4P x 2 (one string to each inverters pv1) until I realized I was wasting watts, now it's 3S2P on each of the 4 pv inputs. These are Canadian solar 420w panels. At the moment it happens, the pv voltage is between 100v to 110v.

Changing param 02 to 10A has no effect.

still chasing this problem. No answers, no solution...