This topic is about repairs and modifications to the internal electronic hardware of any of the 48 V 5 kVA PIP, Axpert or equivalent inverter models. It was started by Walde, with this post and the title PIP Inverter Error "error 09" bus soft start failed. We later moved all the internal hardware related stuff from the PIP-4048MS and PIP-5048MS inverters topic to this one, and renamed it to be more generally about the internal electronics, but not the firmware, of all these related inverters.
There are other topics for aspects other than internal electronics, for the
PIP-4048MS and PIP-5048MS inverters (also called the Axpert MKS 5K), and for the
PIP-5048MK inverter (also called the Axpert King 5K), and for the
PIP-5048GE, PIP-5048GK and PIP-5048MG inverters (also called the Axpert VM II 5000-48, Axpert VM III 5000-48 and Axpert MKS II 5K), and for the
Voltronic InfiniSolar inverters.
- Rinaldo's post with the 2015 service manual
Coulomb's disassembly and reassembly instructions for removing and reinstalling the main board.
Weber's post about upgrading the capacitors and MOSFETs for greater high battery voltage tolerance (updated March 2017). rewinding the large toroidal inductor.
Fan replacement and direction
- Weber begins discussion
T1 Terry's post (see also Weber's post immediately after).
Coulomb's post on the Arctic Cooling fans and their connections.
2015 model Fan "Rectification", i.e. changing direction from blowing down to blowing up.
Original fans put back, due to the fan locked warning issue.
Comparison of temperatures with downward and upward fan direction.
Video of fan replacement without taking the inverter off the wall (7 minute).
- Coulomb's post of the PIP main board repair, with the power flow explanation. Also the Power Flow Topology and block diagram from a service manual. Repair continues. Repair completed with Replacement of the 230 V inverter IGBTs, this time with integral diodes.
Testing inverter gate drivers when the battery-side MOSFETs are removed.
Another repair and a few testing hints.
Replacing the burden resistor fixes error 07 (fault code 07).
Cactus's notes on resistors to check when replacing MOSFETs
- Coulomb's partial schematic trace of the main power supply circuit. Also the utility power supply (where fitted), and the bus soft start circuit.
Partial schematic trace of the inverter IGBT gate drive circuit.
Small trace of the fan locked rotor detect circuit.
Weber and Coulomb's partial schematic for the battery-side MOSFET and 400-V-side IGBT gate drivers for the main DC-DC converter
Coulomb's partial schematic for the reverse protection circuit (where fitted).
Partial schematic trace near the SCC comms connector, including sniff circuit used during dynamic current control patch development.
Partial schematic trace of the Comms Board.
Photos of the SCC board and its pair of relays, and what the relays do.
The red and black wires are NOT SCC output.
Decoding SMD marking codes
- Weber begins discussion
Serial Communications boards
- Coulomb's post with the RJ-45 and D9 (RS232 serial port) pinouts 2013 model and immediately after
Scott's post on the 2014 version.
Weber confirms 2015 pinout, measures voltage sag on +12 V
Scott's comparison of 4 (now 6) RS232 boards.
Replacing your communications board with an Arduino without the microcontroller plugged in. Note safety precautions in the next post.
END MODERATOR NOTES
[Post by weber]
I note that I am now having second thoughts about the need to scale the voltage like this. But here's the schematic for the battery voltage sensing in the inverter/AC-charger section. It is a differential amplifier with a gain of around 1/40.
[Edit: See a photo of the strings of 1 megohm resistors on the main board here.]
Here are the two 100k resistors outlined in yellow (thanks to Coulomb yesterday). Coulomb carefully soldered a 1M 1% resistor on top of each of these, to give us the 10% change we wanted.
Here's the schematic for the battery voltage sensing in the MPPT section.
We hypothesise that the three differential amplifiers with different gains are there to give maximum A-to-D accuracy for the three different battery voltages this device can work with: 12, 24, 48 V. but what is mystifying is that the 3 gains are around 1/4, 1/7 and 1/13.
Interesting the 20w waste heat increase when converting a higher solar input voltage, something the MPPT supporters have been denying being the case, but simple logic said it must as there is so much more heat sink and/or forced cooling required in an MPPT controller compared to a PWM controller.
That extra 20 watts is only 0.6% of the 3200 watts going into the battery at the time. As Kurt said, a PWM charge controller can waste far more power by not collecting it in the first place. It is dissipated as heat in the panels (but any temperature rise it might cause to the panels is probably insignificant since 85% of what falls on them is turned to heat anyway).
[Moderator note: See this post in the PIP-4048MS and PIP-5048MS inverters topic, for why this modification was not pursued.]