this is my first post and I want to begin with appreciating the great work of coulomb and weber allowing me to create a cheap LiFePo4 isle system which is just working fine.
I started experimenting 2 years ago with a PIP-5048MS, 15x300W modules and 4x12V lead acid camping batteries and spent 1 year of upgrading the system to what I have now...
Here is a short overview of my system (running fine for a year now):
I have 4 PIP-5048MS (patched firmware 72.20e) working in parallel mode charging 8 LiFePo4 15S Pylontech US2000b+ batterie modules (17.6 KWh, constant voltage 52.7V, float voltage 51.7V) (no dynamic charge control yet).
The inverters are connected to 4 PV-arrays of sizes 6.3, 5.4, 3.6 and 3.6 KWp.
Furthermore 2 of 4 inverters are connected to grid-power to be able to bypass the isle system when the batterie's SOC gets below 20%.
All 4 inverters power the house, a Tesla Model 3 and crypto miners creating heat to warm up the basement
, if there is too much energy provided by the PV modules.
Several relais controlled by a raspberrypi help to cut off the PV-arrays and disable/enable the "active" switch of the inverters to shut them down or bring them up.
A state model programmed in python decides how much inverters are active depending on the load or when to shut down inverter 3 and 4 to make inverter 1 and 2 switch to grid when batterie SOC gets below 20%.
For this "controlling" the batteries and inverters are read out every 5 seconds by rs232 and rs485.
I am very happy with what I have create so far. Sometimes the fuses between the inverters and batterie might trigger, when the load increases dramatically and the bringup of more inverters takes too long. The same sometimes happens when the PV-arrays produce low power or for any strange reason I do not understand the SCC suddenly reconnects to the PV-array shutting down PV power completley for a few seconds (no settings have been changed). I think I can fix the fuse issue by utilizing more expensive ones. The fuses that are currently applied should trigger at 120A (25mm² cables) but they already trigger at 70A - 80A because of thermal heat generated at the contactors of the fuses...
However the reason for my post should address the RF noise generated by the PIP-5048 inverters.
I read this post and I can confirm that I have much noise in the range from 6Mhz to 18MHz and higher disturbing my DSL signal.
Monkeytom wrote: ↑
Sat, 04 Apr 2020, 08:45
Well I have had the two PIP 5048MS inverters installed a couple of weeks now, and have noticed two interesting things. First the mppt solar charge controllers do not input nearly as much power to the battery as the old PIP 4048HS units. My solar panels are running about 70 volt dc in. And second to that and more importantly to me the PIP 5048MS are taking out my ham radio, they are very dirty RF wise. And generate lotsa QRM. So I will go back to the PIP4048HS charge controllers and see if what I think is happening is? Anybody else experience this? The noise is particularly bad on 6 meters my favorite band. Tom
See my picture to get an idea of how the DSL signal is disturbed by the inverters.
The upper diagram shows the noise margin of the signal at different frequencies. The higher the yellow and purple margin the better.
The orange line shows the maximum and minimum margin over a whole sunny day. At night the orange noise-margin is at maximum and the spectrum displays smooth blocks.
But at day the blocks transform to a very curly shape starting dramatically from 6MHz up to the end of the diagram.
The minimum orange line is reached when the PV-arrays produce most power. At this point, my DSL signal only achieves about 70 MBit/s from about 120 MBit/s maximum.
I noticed this last week, when I moved the location of my internet modem/router direclty to the telephone wallbox of the house to get the maximum broadband speed.
The router is about 5 meters away from the inverters. Cutting the PV-arrays off completely eliminates the noise and the DSL signal is perfect.
Most of the noise is coupled by an ethernet cable that runs parallel with the PV strings for a few meters. But there is still some radiation noise the affects the router when the ethernet cable is disconnected.
Obviously the switching of high currents within the inverters leads to RF noise that is escaping the inverters using the PV strings as antennas.
So I am trying to reach out to you if anyone else is fighting with RF problems and might have some hints to compensate this problem.
Next week I will try to put ferrites around the string cables.