Good day,

 

I have picked up on a issue I am having where, I am running the Pylontech on battery mode and then for a second or 2 the battery voltage goes all the way down to 44volts, this then causes the Inverter to go back to Grid.  I have manually tested this by checking both ICC and Watchpower, and on ICC setting the inverter mode to Eco and then to battery.

 

now this does not happen every time but each time I am happily on battery mode and then the next I am back to Utility mode.  I tested it and it does the same.

 

another thing yesterday when this happened the inverter restarted and all power went off,  I did smell some burning wires for a short period.  however after that the same issue still happens but have not smelt anything strange again.

 

what could be the cause of this issue?

 

I have 2 x pylontech US2000B batteries and a 5KV king Inverter.

 

 

17 hours ago, Etiennet said:

then for a second or 2 the battery voltage goes all the way down to 44volts, this then causes the Inverter to go back to Grid.

what could be the cause of this issue?

Are you using battery type PYL?

If not, what is your bulk/absorb voltage setting (setting 26)? If it's high (e.g. 53.2 V, as recommended by Pylontech), then the inverter will often overshoot, and as soon as the battery voltage passes 54.0 V, the Pylontech disconnects altogether from the inverter. This will cause the "battery" voltage (now really just the capacitor voltage) to plummet.

Do you perhaps have too high a PV voltage? Anything above 145 V will cause the PV to stop producing altogether. But I would not expect that to cause the battery voltage to drop that low.

1 hour ago, Coulomb said:

Are you using battery type PYL?

If not, what is your bulk/absorb voltage setting (setting 26)? If it's high (e.g. 53.2 V, as recommended by Pylontech), then the inverter will often overshoot, and as soon as the battery voltage passes 54.0 V, the Pylontech disconnects altogether from the inverter. This will cause the "battery" voltage (now really just the capacitor voltage) to plummet.

Do you perhaps have too high a PV voltage? Anything above 145 V will cause the PV to stop producing altogether. But I would not expect that to cause the battery voltage to drop that low.

Hi Coulomb,

 

Further to add last night boiled the kettle and then power went off and back on, then went to the system and F56,

 

This is a photo of the batteries.

 

 

I was using the Setting PYL

System this morning is still on f56 and on ICC I can see fault.

Keep on getting these emails from the system every now and then

 

[Battery under shutdown], Fault Time : 08:15:45

 

The PV Volt has not gone above 100v if I am not mistaken it is always in the 90 to 95 V

 

 

No PV watt today probably because of the system in fault mode.

This is also what ICC and Watchpower is reading from the battery Volt

6 hours ago, Etiennet said:

boiled the kettle and then power went off and back on, then went to the system and F56, ...

[Battery under shutdown], Fault Time : 08:15:45

So F56 is battery not present. This is consistent with the plummeting battery voltage reading, and the emails from the battery BMS.

So the question is what is causing the battery to shut down. It claims that the problem is "battery under", which sounds very much like the battery voltage is too low. Yet both battery modules in the photo are showing 5 out of 6 LEDs on.

Is there perhaps an issue with your battery wiring, or the battery fuses? For example, do the metal caps of the fuse(s) have black splats from a lack of pre-charge? My understanding is that Pylontechs automatically limit the turn on surge current via the MOSFETs, but the turn-on surge current could still be upwards of 100 A, plenty to make a mess of the fuse connections, possibly causing high resistance and/or intermittent connection.

Thanks Coulomb,

I am no electrician by any means but I did open the KETO Fuse holder and inspected the Fuses could not see any black splats at all (though I might have missed it), Closed the KETO Fuse Holder and still the same, Perhaps it could be the cabling but the Electrician will only be onsite on Friday.  I really need a better Electrician because I am not happy with the install at all.

Any way, Perhaps the burning smell that I smelled on sunday night could be from the battery wiring? and with boiling the kettle it caused further damage to the wiring?

If it is the wiring would this then be the fault of the installer or electrician? Because at this stage its a blaming game.  Been told its the settings and that the install is perfect.  But I still think the fact that I smelled burning from the install and that the power tripped means there is more at fault then "settings"

15 minutes ago, Coulomb said:

So F56 is battery not present. This is consistent with the plummeting battery voltage reading, and the emails from the battery BMS.

So the question is what is causing the battery to shut down. It claims that the problem is "battery under", which sounds very much like the battery voltage is too low. Yet both battery modules in the photo are showing 5 out of 6 LEDs on.

Is there perhaps an issue with your battery wiring, or the battery fuses? For example, do the metal caps of the fuse(s) have black splats from a lack of pre-charge? My understanding is that Pylontechs automatically limit the turn on surge current via the MOSFETs, but the turn-on surge current could still be upwards of 100 A, plenty to make a mess of the fuse connections, possibly causing high resistance and/or intermittent connection.

 

Looks to me as if you are overloading the batteries. max current for 2 US2000C is 50A which is approx 2400W.

Quite correct, @Tinbumthese are not 1C batteries. However, the ADD switches will need checking also. So in order to unlock the full 100A of the Batteries you will likely need 4 units. One of the very reasons I don't like these batteries. Its the weak point of this system. However, the battery voltage dropping is the BMS protecting the battery. 

I have a similar situation at another customer who has the Kodak Force 1 which is basically a Pylontech Force 1 that has the same discharge output limitations. He has the OG10.0 or MAXII 10kW inverter and guess what the battery is stacked to 10.5kWh but has a hopeless discharge limit of 100A. The same footage of the BMS infers. See below. The only way to get the full potential is to parallel two banks or have two BMUs. 

Check the battery voltage in the attached pics. Massive dips in voltage. 

In the same way your system is constrained, this is exactly the same. The limits are different values but the battery BMS is doing what it is designed for. 

This particular Installation has good equipment but unfortunately put together by an electrician with little solar experience. This Battery is well suited to a 5kW inverter like the King but not to the OG10.0. 

 

Thanks for the replies gents.

Still trying to understand why it only became an issue now? Everything was working 100% (after some initial install issues on the panel side that was also addressed on this forum which turnedout to be panels wired incorrectly) at my old residence. When I relocated to our new home the issues started. 

Also the fact that I smelled burning wires from the installation is worrisome.

The inverter is running only essential equipment. No stove, geyser or pool pump.

At the old residence the geyser was on a timer but never had these issues.

Would the BMS not then shut down the batteries until the load % goes down?

My average load percentage is never more than 30% at the most. Except when the kettle is boiled. But surely the inverter should use the excess power from the grid no?

Its been 24 hours now and still the f56 error and battery shutdown error.

Again system was working at old residence with out these issues. Also i had 4 x 405w panels at the old house and now its 6 x 405w panels.

When this f56 issue is resolved would that then mean that the system is not sufficient for my needs? Basically as backup system for loadshedding and also saving on electricity costs.

There wont be any funds anytime soon for an additional battery. And when there is it would be another US2000b as the 3000b or c is out of my price range.

Thanks again for all your input gents.