System comprises MultiPlus-II 48/5000/70-50, MPPT 150/100, Battery Monitor BMV-712, Venus GX. This is a new installation, and have upgraded everything to latest firmware.
The final system will be entirely off grid in a remote location, but is being initially commissioned in a residential area for convenience. As the backup generator is at the remote site, am attempting to use a plug in connection to the mains grid to simulate the generator, but this is being rejected by the Multiplus 2.
The AC connections currently around the Multiplus 2 are:
Multiplus 2 earth stud and the Battery 0V both connected to a stake in the ground (no connection with the grid installation)
AC OUT 1 Only connected to a 3 pin socket via and RCD, no connections to anything else
AC IN connected to a mains GPO via a 3 pin plug. This lead is about 8 m of 15 A rated caravan extension lead , no more than 1.5 mm2 conductors. I am aware this may be an issue with Loss of Mains (LOM) detection.
When the mains (within the allowed limits) is connected to AC IN,
1. If the inverter is running, it syncs the inverter frequency to the AC IN frequency over a few seconds then it tries to connect. AC OUT 1 output goes off for a fraction of a second as it tries to transfer and reverts back to inverter mode. AC IN goes to disconnect state, with no indications why it failed.
2. If the inverter was not running (due to low battery volts, or inverter turned off) the AC OUT1 comes on for a fraction of a second as it tries to transfer , then drops , and goes to AC in disconnect mode, and the Multiplus 2 is then in off state . Also no indication as to why it failed.
I have looked extensively at VeConfigure3, Victron Connect, Venus GX and VRM., and nothing indicates anything is wrong, other than the AC IN is disconnected.
Independent monitoring of volts and frequency at the Multiplus 2 AC IN terminal agrees quite well with the values indicated from Multi, and the AC current always stays very low – ie the charger never starts (it should as the batteries are quite low now), as confirmed by nothing indicated on the front panel LEDs. There are no dips or spikes obvious on the AC voltage. Grid AC voltage for my testing on AC IN has always been within a couple of volts of 245 VAC , well within the allowable limits set in the parameters.
Things I have tried include:
- Searching other community posts
- UPS feature on and off, no difference.
- Loss of Mains detection temporarily disabled (to prove the relatively small diameter cable to AC IN isn’t the issue)
- Monitoring the AC voltage at AC IN terminals – no dips or spikes found
- Confirmed the AC IN neutral is within a volt or so of earth potential
- Temporarily disconnected various parts of the earthing system
- Disconnected the VE bus from the Multiplus 2 , so it is independent of Venus GX
- On the Venus GX, System Setup, AC input 1 - tried all possibilities – Grid, Generator, Shore Power ( I suspect it is only text, and doesn’t change parameters in the MultiPlus 2)
I cannot find a comprehensive list of the causes of AC in disconnect. The ones I am aware of are average ACV too low or too high, Instantaneous ACV too high (265V) , frequency out of acceptable range , Loss of Mains Detection.
Are there any other causes of AC disconnect ?
What should I do next ?
Thanks in advance for community assistance.