Solis RHI 5kw + Pylontech US500 not stopping discharge at defined SOC

[paul-home]

Glad to ear it! However, I am afraid that the challenge continues and it might not be such a permanent fix as I thought:
- I have to go back and adjust the charging time settings about twice per month. This might depend on the changes in the meteo conditions and sunset times.
- At least once, the "Allow charge from grid" seems to have switched back to "Do not allow" by itself.
- In the last week, I also received 3 BMS alarms on different days, while the SOC was well above the lower threshold. When checked, I found that one of the three batteries had all LEDs flashing, including the red, and the beeping alarm on, while the other two were powering my house normally. The flashing battery was not always the same (twice the top, once the bottom one). Once I restarted the system, the flashing battery seemed to be full (all green LEDs on), and balanced the charge with the others in a little while. This behavior was much more frequent before I applied my fix, and it seemed to have disappeared for more than a month until recently.

I have the Solis integration for Home Assistant installed, and I noticed something else. If you toggle the Battery wakeup switch and / or Feed in priority mode switch, the drain on the battery stops (i.e. goes from ~30w to zero). This is something that could be easily automated in Home Assistant. This problem is clearly a bug in the inverter firmware.

 

[Solar Guppy]

Batteries have electronics in them for the BMS and balancers ( which require energy to operate ), either it uses the battery cells for power or inverter will have to provide the energy from other sources, this is what I believe you are seeing and toggling features just changes where the energy is coming from.

 

[paul-home]

Batteries have electronics in them for the BMS and balancers ( which require energy to operate ), either it uses the battery cells for power or inverter will have to provide the energy from other sources, this is what I believe you are seeing and toggling features just changes where the energy is coming from.

I'm not sure you understand the problem described in this thread

 

[padresalato]

My inverter is the S5-EH1P4.6K-L-DC with 4 pyl US2000C. I had the problem descibed in this thread. I had another problem: when enabled the Battery Reserve Switch, on this trigger the batteries start to charging by absorbing about 5kW from the grid, without any possibilitiy to limit this value. I tried all the solutions descibded suggested above without success. So i decided to open a ticket, on the italian Solis portal, on thursday 22 February at 14:00. At 14:02 i received the request to provide picture and serial number of my inverter. I replied immediatly. On friday 23 February at 08:47 i received an email from italian Solis service: "Good morning,We have updated the firmware of the inverter and now the batteries no longer download to 150W. In any case, it is possible that in some cases the batteries fall below the percentage of Overdischarge and getting to that of Force charge, load from the network forcefully. Charging from the mains is now also limited to 500W. Let’s test the behavior of the system in the next few days." Now is Saturdy morning and the batteries have no providedy current for all the day below the Overdischarge SOC. I'll check this for the next days. For the other problem I'll have to check.

 

[padresalato]

yesterday

 

[Copernico]

yesterday

Interesting, I am curious to see how long this will hold. (Though, I could not see the % scale on the right of your attachment.) The next time I get the inverter to switch to "do not allow" by itself, or some other strange behavior, I will try to open a ticket as well.

 

[padresalato]

sunday-monday

 

[padresalato]

Update. In these cloudy days, the SOC remain at the Overdischarge SOC level. It's reduce for 1% in about 18 hours. Remain the problem of the abnormal absorption power during the Battery Reserve Switch cycle. I wrote ot Solis cs.

 

[peufeu]

I don't know if this is the same issue you have, but...

At night when the battery reached overdischarge SOC my S5 6kW would stay on and slowly drain it. So I programmed the Pi:

- When MPPT voltage is low (means there is no sun) and Battery SOC < 20%, turn the inverter off

- When MPPT voltage is high (means there is sun), turn the inverter back on

In the OFF state it uses almost no power, but it still answers modbus queries. This solved the problem. It's a pity it doesn't do that automatically.

What voltages "high" and "low" are depend on how many panels you have, etc.

 

[padresalato]

Update. I confirm, with the new firmware, the SOC remain at the Overdischarge SOC level. It's reduce for 1% in about 18 hours. For the abnormal absorption power during the Battery Reserve Switch cycle, nothing to do. Before they try modifying the Max. grid power when Force charging with unsuccess. After they the modify the Time of Use Charge Current Set putting a max limit on it. This modify works, but limit the charging current always, so the power to the battery is low. This modify they made before my agreement and the ask to remove it. At the end the Battery Reserve Switch cycle works as long as your incoming power form grid is grater than the power absorbed by the batteries. In my case 50V*100A=5kW is higher than my grid power, 3kW, and so is unisable. One note: the Solis customer service intervenes promptly but make modifications without permission and this could be unwanted.

 

[Viip]

Had the same issue as OP, my setup:
Inverter: S5-EH1P6K-L
Batteries: Pylontech US5000 x2

Contacted Solis who upgraded my firmware to 490045, made no difference, batteries still draining, in my case, 25W no matter what I set the storage mode to.

Contacted Pylontech and they asked me to check the can bus cable, specifically the colour of the tags, in my case white. Was told that this was the wrong cable should be using the one with the blue tags, pins 1/2/3 should not be used.

Had a cable lying around chopped off Pins 1/2/3 and sure enough problem solved, battery stopped discharging and now idle.

 

[padresalato]

Had the same issue as OP, my setup:
Inverter: S5-EH1P6K-L
Batteries: Pylontech US5000 x2

Contacted Solis who upgraded my firmware to 490045, made no difference, batteries still draining, in my case, 25W no matter what I set the storage mode to.

Contacted Pylontech and they asked me to check the can bus cable, specifically the colour of the tags, in my case white. Was told that this was the wrong cable should be using the one with the blue tags, pins 1/2/3 should not be used.

Had a cable lying around chopped off Pins 1/2/3 and sure enough problem solved, battery stopped discharging and now idle.

Hi Viip, a couple of questions: you wrote you've changed the cable connection. Before this, the inverter can read the battery status or not. Now you're batteries are in idle. Did you meausure, with a dc clamp, if there some current from the batteries? Because mine show zero current on the solis, but is not true, some curren flow to the inverter. Thank you

 

[Viip]

Hi Viip, a couple of questions: you wrote you've changed the cable connection. Before this, the inverter can read the battery status or not. Now you're batteries are in idle. Did you meausure, with a dc clamp, if there some current from the batteries? Because mine show zero current on the solis, but is not true, some curren flow to the inverter. Thank you

Hi Padresalato,

The inverter was able to read the status with the original cable which was a straight pin to pin on all 8 connectors.
And for reference I have also attached the pin outs required for the can cable they sent me.

I have attached a DC clamp, see attached. I find that as long as the batteries are idle no charge is being drawn.

Also Pylontech advised me to check the following, in my case I did need to change the defaults, this may also have helped.

"As the inverter is a Solis, please change the following settings if they haven’t already, as there is an error in the preset settings for Pylontech batteries. Battery Overvoltage needs to be changed from 60V to 54V and battery undervoltage needs to be changed from 42V to 45V."