Hi,
I have a three phase MultiPlus II 48/15000 setup, with two MultiPlus II units in parallel per phase. So: 3x 2 times a MPII 48/15000.
The system is working great, combined with 180kWh storage (Pylontech 36x US5000) we can greatly exceed the grid capacity of 3x50A.
However, when maxing the setup, either by charging the batteries at max. grid capacity, or max. dumping back to grid from the batteries, L3 is staying behind in Watts, Amps.
I have a VM-3P75CT at the grid side, and I noticed something was off. When maxing, this is what it looks like (see L3 vs L1 and L2):
As you can see L3 doesn't max.
However, if you look at what the MPIIs for L3 report themselves, it thinks it's maxing:
So my first thoughts were:
- Maybe the VM-3P75CT is faulty
- Maybe a configuration problem @ MPII two at L3
- Maybe the VM-3P75CT connected current clamp on L3 is faulty / not properly installed
- Something with an insane power factor (AC? Pump? shut both off, issues persists)
- Let's measure
Swapped the VM-3P75CT: same. Swapped the clamps: same. Shut the AC & pump: same. Checked the configuration for all the MPIIs in VE Configure: same (AC current limit 25A per MPII, no dynamic current limiter)
Measure:
Grid to AC busbar L3: |
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Busbar L3 to MPII one: |
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Busbar L3 to MPII two: |
Things I found and made sure to check (but check out):
- The MPIIs are all the same hardware generation
- The AC cabling is the same size & length between AC busbar & MPIIs
- The voltage on L3 form grid is higher. I raised the inverter set voltage to 240 to increase delta, but no change.
So L3 is running almost at half capacity. I hope someone here has an idea... As I feel all next steps are quite extreme (re-wiring, replacing MPII, etc.)
That is mind boggling to me is the fact that the system itself reports maxed amps on L3. So really the only thing that makes sense to me at this point would be that the MPII two on L3 has a faulty current meter, and thinks it's maxing (so it caps out not to exceed the configured 25A per MPII per phase), wile it isn't?
Another interesting finding is that, if I use VEConfigure to change the max amps on L3 one to say 15A, and L3 two to 35A, I get the same thing with the new limits. MPII "L3 one" is doing all the work (maxing), and "L3 two" is barely doing anything.
Which suggests a problem with "L3 two", right?
Yours,
Wietse