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Growatt 12k MPPT Charging Question

J.P.

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Oct 9, 2020
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Texas
A few days ago I got the Growatt Shinelink up and running on my remote building (drove up there after work Tuesday night to install the T-Mobile Test Drive Hotspot) and now I can monitor my remote building during the week when I am not there. Yesterday morning the MPPT kicked in and solar production began at 6:45 AM. Today is a similar (partly cloudy) day but it is 8:45 AM and solar production has not yet begun for the day.

The battery was full (54.9V) yesterday by 9:45 AM and stayed (essentially) full for the entire day and the MPPT was still working and covering the loads which were varying from 250W up to 2200W all the way till dark last night when the solar production eked out its last 14W and shut off at 8:10 PM.

Overnight the battery was drawn down to 48.0V (loads varying from 250W to 1800W) but still no solar production yet this morning 2 hours after it began yesterday morning.

Does anyone have any idea why it has not started producing solar today to service the loads and recharge the battery?
 
Not specific to your unit, but sounds similar:

 
A few days ago I got the Growatt Shinelink up and running on my remote building (drove up there after work Tuesday night to install the T-Mobile Test Drive Hotspot) and now I can monitor my remote building during the week when I am not there. Yesterday morning the MPPT kicked in and solar production began at 6:45 AM. Today is a similar (partly cloudy) day but it is 8:45 AM and solar production has not yet begun for the day.

The battery was full (54.9V) yesterday by 9:45 AM and stayed (essentially) full for the entire day and the MPPT was still working and covering the loads which were varying from 250W up to 2200W all the way till dark last night when the solar production eked out its last 14W and shut off at 8:10 PM.

Overnight the battery was drawn down to 48.0V (loads varying from 250W to 1800W) but still no solar production yet this morning 2 hours after it began yesterday morning.

Does anyone have any idea why it has not started producing solar today to service the loads and recharge the battery?
I have observed similar behavior with both of my growatt SPF-12k inverters. About once a month, the MPPTs in one of the units won’t “start” even though the PV voltage is well above the startup voltage and the battery voltage is well below the charge cutoff voltage. If I change the cutoff voltage setting from say 56.4 to 56.5, the system SCC starts working. Since both inverters are exhibiting this behavior and they are different models (an SPF 12000D DVM and an SPF 12000T DVM-MPV) I’m betting it’s a firmware bug. Both units have the latest firmware AFAIK.
 
I had another instance of this yesterday. We were at the building all day on Saturday and the sun was out but there were quite a few clouds throughout the day and we ran the AC units (and left the doors open all day as we were going in and out) and power tools (including a welder) and lights and cooking and by the end of the day the battery was only about 1/3 full. Later in the evening the unit went on bypass as the battery reached low voltage. Late yesterday afternoon I pulled up the Growatt app to see how it was doing and it was still on bypass. In fact it had never started charge in the morning.

We drove up there and everything was fine except the SPF 12000T DVM MPV Inverter was just not seeing the panels. There was power from both arrays going to the inputs but it just did not see them. I turned off the breakers from the solar arrays and then turned them back on but that did not do it. I tried a few other things but finally just switched the building onto the grid (completely taking the inverter out of the loop) I then flipped off the arrays, turned off the grid power into the inverter and then turned off the inverter and let it sit for a few minutes. I turned the inverter back on, then turned the array breakers back on and it finally recognized them and started charging the batteries.

I then turned grid power back on to the inverter and ran through the programming to make sure nothing changed, it was all as it should be so I flipped the building back onto the inverter. It immediately went into bypass (as the battery was still low) and continued charging the battery from solar for the rest of the day and this morning it started back up as usual.

I really wish I could figure out what is causing this, the most efficient way to reset it, and if there is any way I can reset it from a distance through the app. One additional problem that I have it that the Shine link does not always come back on when I turn off the inverter unless I unplug it and plug it back in separately after the inverter is back on.
 
I had another instance of this yesterday. We were at the building all day on Saturday and the sun was out but there were quite a few clouds throughout the day and we ran the AC units (and left the doors open all day as we were going in and out) and power tools (including a welder) and lights and cooking and by the end of the day the battery was only about 1/3 full. Later in the evening the unit went on bypass as the battery reached low voltage. Late yesterday afternoon I pulled up the Growatt app to see how it was doing and it was still on bypass. In fact it had never started charge in the morning.

We drove up there and everything was fine except the SPF 12000T DVM MPV Inverter was just not seeing the panels. There was power from both arrays going to the inputs but it just did not see them. I turned off the breakers from the solar arrays and then turned them back on but that did not do it. I tried a few other things but finally just switched the building onto the grid (completely taking the inverter out of the loop) I then flipped off the arrays, turned off the grid power into the inverter and then turned off the inverter and let it sit for a few minutes. I turned the inverter back on, then turned the array breakers back on and it finally recognized them and started charging the batteries.

I then turned grid power back on to the inverter and ran through the programming to make sure nothing changed, it was all as it should be so I flipped the building back onto the inverter. It immediately went into bypass (as the battery was still low) and continued charging the battery from solar for the rest of the day and this morning it started back up as usual.

I really wish I could figure out what is causing this, the most efficient way to reset it, and if there is any way I can reset it from a distance through the app. One additional problem that I have it that the Shine link does not always come back on when I turn off the inverter unless I unplug it and plug it back in separately after the inverter is back on.
I found with solar assistant I could fix this exact issue by going int the configuration menu, click the “settings “ link on the inverter status line, select the misbehaving inverter from the list (if you have more than one), select the “edit” link on the Battery Settings option and change the Battery Bill Charge value ( I charge mine from 56.4 to 56.5 but you can probably select any reasonable value). Save it and the system will recognize the solar voltage and startup the MPPT charge controllers. I suspect there is a firmware bug that causes the issue (probably stuck in an invalid state) and that writing data to the MPPT register via the app, causes the controller to reset the control loop and start working again (until the next time the conditions are just right to hang the control if code.

I wish the source code was public domain so I or others could find the bug and fix it.
 
I requested the Firmware update from Growatt a few days ago but they refused to give it to me. They say my problem only happened one time recently and if it happens again soon they will consider it. They also let me know that they can monitor my system remotely (without my permission). I am sure it's in their fine print somewhere.
 
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