Electricity Meter Com Fail / weird issue

Hi All,

Since my installer moved my ac3 + 2 x9.5 batteries from the loft into the garage, I have been receiving  "Electricity Meter Com Fail" errors. My installer has been out a few times and tried changing the new solar meter that was installed, but I was still receiving errors. I've sent my installer quite a few emails, but I'm lucky to get a reply, and if I do, it's only a few words. To say I'm starting to get annoyed would be an understatement

After a few days of data collection and testing, I've noticed a weird problem that is related to the coms error. I have a bedside touch light that randomly stops working since the system was moved. I've noticed that when the inverter is showing the coms error then the touch light is also not working. The error also only occur when the inverter is only at full power charge / discharge. After trying lots of things I found that as soon as the light is not working and the inverter is showing the error if I go into Givtcp and set the max charge / discharge power (depending if it's charging or discharging) to 2800w or below the touch light instantly starts work and the error on the inverter clears. To stop Predbat returning the charge / discharge rate to 3000w I've added inverter_limit_charge: 2800 and
inverter_limit_discharge: 2800 to my Predbat config file. Locked to 2800w I have no problems.

Video showing of me showing how to get the light working / clear the fault here https://mustyweb.co.uk/ge/how_to_clear_error_and_get_light_working.mp4

I've tried plugging the light into different circuits- even the inverter eps socket but will not work until I drop the power rate.

When the inverter and touch light are working ok If I place the touch light so part of is touching a bare metal fitting on a radiator. the touch light stops working. With my limited electric knowledge I presume the light stops working when it comes into contact with an earth so could the inverter for some reason at full power is causing fault and the light detect an earth and this also leading to the coms error.

Anyone come across this error or have any ideas please ?

Thanks

Certainly weird I'll give you that.
This does sound a little stray earth path / neutral earth cross fault kind of oddity. In "on grid mode" the AC3 inverter earth runs in "pass through" mode so your house / grid earth should be continuous no matter what.
As houses age and get things added to them the chance of DIY or other wiring mistakes increases (adding circuits to rings but ending up with things crossed is not beyond the realms of possibilty). A poor grid earth should have shown its hand during testing of the inverter install with crap Ze/Zs readings.
If your on TT earth rod though these readings are only really useful on the day of test as ground conditions can move these readings around.

Ideally I'd suggest you get an electrician in to check everything top to bottom in the entire house but this will probably be a bit of a cost.
What might help to narrow things down is to switch off circuits one at a time (lights, ring mains etc) and, using your handy new touch test lamp weirdness see if you can narrow down to a certain part of the house.

amust With my limited electric knowledge I presume the light stops working when it comes into contact with an earth

I'd guess this just interferes with the detection mechanism in some way. I assume you are acting either as an earth or as a sink of static charge or something which is how it detects your touch. (Some sort of change in capacitance.)

I'm way out of my depth here, but could there be a poor neutral connection somewhere, so that a high power is pulling up a voltage somewhere? Possibly depends on your house's earthing system? If you have EPS does that mean you have an earthing rod?

hoggy Thanks for the reply

The system in it's previous location had worked flawlessly for over a year. I've only been having problems since it was moved. The only additional wiring was from the same CU to the garage.

We have an earth rod (installed many years ago) but now with the system in it's new location the inverter is a fair distance from the earth rod. As for testing a cannot say if they did or did not test. I've just tipped a few buckets of water around the earth rod and put the charge rate back up to full power to see if maybe that makes a difference.

I've also tried turning of circuits off while the error is present with no joy.

Yesterday if was ok for most of the day and then late afternoon out of no where the error was back and only fixed by dropping the power.

amust

I had something similar that the battery would fault if under full load, after a new BMS board didn't fix it. It turned out to be a dodgy cable that when it got hot under full load there was a comms circuit failure, then when it cooled down worked again. GE replaced the cable and it has worked flawlessly ever since

DD Thanks for the reply

yes we having an earthing rod that was installed many years ago way before the inverter and batteries where installed.

I probably should of added in my first post that the inverter continue to charge / discharge at full rate even when is showing the error.

It does seem to me to be an electrical interference problem. The inverter running at maximum power will generate more interference (in the 100kHz + region). If you have a portable radio with long wave you could use that to check for interference strength and how it varies with power. Good earthing is important.

amust the comms between the meter and the inverter is not specifically grounded (no ground connection either end) which, depending one the type of cable involved can be susceptible to pickup / induced signals.
Daft question but the N and E on the grid side of the inverter aren't transposed are they.

hoggy Hi
cat6 cable has been used. The solar meter is located in the loft and the grid meter is downstairs using a lora to send the signal up to the loft. Then from receiving lora cat6 runs to the solar meter > combines and then run to the shed.

Daft question but the N and E on the grid side of the inverter aren't transposed are they.

I've no idea that's above my skill level

So which meter is having problems with comms?

Not use about AC3, but hybrid inverters only communicate with the grid meter. The 'solar meter' serves no useful purpose, but seems to be required by MCS regs or similar.

If it's LORA comms to the meter it's only 2 wires (even though you may use cat 6 cable). You should get a flashing light on the LORA receiver if it's getting data from the meter. See if that stops flashing when you have the problem...

rjp I'm not sure what meter it is. currently the error is active, looking and both 120 meters they both have flashing red lights and the lora has green flashing lights on both send and receive.

I went into the loft and turned all the breakers off in the loft CU apart from the breakers for inverter and for the solar meter but still the touch light would not turn on.

Then I went to the downstairs CU that feeds the loft CU. first I tried turning all the light breakers off but still the touch light would not turn on. Next I tried the breaker for the kitchen sockets and the light starts working. doing the same for other socket circuits also makes the light work. but it stops as soon as I turn the socket breakers back on.

still the only way I can get the light working and to clear the error is to drop the charge / discharge rate back to 2800