MPP PIP–1012LV-MS Solar amps / MPPT limit seems lower than spec

[willo23]

I know there have been lots of threads on the MPP PIP-12012LV-MS, in general its voltage control and amp monitoring probably isn't going to be super accurate. Maybe I'm just expecting too much from an inexpensive box? My other MPPT experience is all Victron stuff so maybe I'm spoiled there.

What I'm seeing is that while I have it overpaneled, I never seem to get more than about 31A or 440W out of the MPPT output to the combination of (inverter load + battery charge), when in theory it's suppose to max at 40A /500W.

What I'm doing--
-2x 370W panels in series, so 2x Vmp 38.3v, Imp 9.7A, keeping me reasonably under max Voc
-A constant 50W load on the inverter
-100AH lifepo4 (ampretime) discharged down to about 12.7V
-Bulk set to 14.5V, float 13.6V, max charge Amp settings on the MPP at 50 or 60A

What I see is that--
In full sun It does run at 78v, but flat-lines out at about 5.8A on the solar string (78*5.8=452W), and reports PV watts 420-440W. All these values match up when checked with clamp meter, solar-assistant.io, and the LCD display.
Solar-assistant makes it really easy to see, the flat-line in PV watts&amps during solar peak 10am-2pm


I still need to double check the panels alone and with another controller I guess.
Has anyone else been able to see a true 40A/500W from the PIP-1012LV-MS?

 

[willo23]

This shot from solar-assistant maybe shows it
Panel #1 alone, 250W out
Panel #2 alone, 250W out
Panels #1 & #2 in series, 430W out
Either the current is being limited on the output, or the MPPT is mistracking somehow.

 

[nettrust2]

Measure your battery voltage/SoC while you are applying max charging power, make sure they still read 12.7.

As SCC will taper down power when it senses battery is near full (and receiving high PV power).

SCC will usually read higher than idle voltage when charging.

Perhaps try running a high load too, while monitoring PV power.

Without tight / accurate BMS communication to determine actual voltage, all bets are off.