I have a Solis 5kW inverter (model S6-EH1P5K-L-PRO) and a Sunsynk 5kWh battery (model SUN-BATT-5.32 with serial number starting with SSLR so a rebranded Eenovance).

After a day without the grid with the battery on the low end it will charge to full at only 180W and that can take a full day.

That's less than 4A whereas the battery spec says maximum charge is 100A

Surely this is not normal?

Any idea how I can fix this?

22 hours ago, biometrics said:

I have a Solis 5kW inverter (model S6-EH1P5K-L-PRO) and a Sunsynk 5kWh battery (model SUN-BATT-5.32 with serial number starting with SSLR so a rebranded Eenovance).

After a day without the grid with the battery on the low end it will charge to full at only 180W and that can take a full day.

That's less than 4A whereas the battery spec says maximum charge is 100A

Surely this is not normal?

Any idea how I can fix this?

Have you checked the maximum charge and discharge setting under the battery/system settings. Not sure what sections Solis if se for these settings?

Both set to 100A.

If the data cable is faulty or incorrectly plugged in, is this typical behaviour?

Have you tried "USE"(manual user mode for dumb batteries without BMS) mode and set you all your battery parameters manually to see if it then behaves differently?

5 minutes ago, zsde said:

Have you tried "USE"(manual user mode for dumb batteries without BMS) mode and set you all your battery parameters manually to see if it then behaves differently?

Ah ha, worth a try before I replace cables.

Edit: seems it’s not a great idea running it in this mode.

Edited April 3Apr 3 by biometrics

1 minute ago, biometrics said:

Ah ha, worth a try before I replace cables.

It could be a faulty cable, or that the pionouts do not match either on the Inverter or Battery BMS side, or the BMS Protocol mismatch
Remove the comms cable for the User mode test

Edited April 3Apr 3 by zsde

13 minutes ago, zsde said:

It could be a faulty cable, or that the pionouts do not match either on the Inverter or Battery BMS side, or the BMS Protocol mismatch
Remove the comms cable for the User mode test

If it is indeed a cable issue, does it make sense that it charges slowly like this?

I mean, is this the typical safety mode?

17 minutes ago, biometrics said:

If it is indeed a cable issue, does it make sense that it charges slowly like this?

I mean, is this the typical safety mode?

Faulty comms could cause numerous issues I would assume, but I cannot answer whether the slow charge is one of the side effects.
Do a test without comms to determine if the BMS is working as it should. If it does, then check all the pinouts for the Inverter comms RJ45 (I assume it's an RJ connector) and also the Battery pinouts for comms. Furthermore check the Inverter comms protocol matches the Battery protocol. I don't what BMS is used but if it's Pace, then the Pylontech protocol will in all probabilty be the one to use.

On the soliscloud app, under device -> battery, see what the amps are registered here.

Is grid charging turned on or off? If off, do you have enough solar to support your house load then charge?

17 hours ago, biometrics said:

If it is indeed a cable issue, does it make sense that it charges slowly like this?

I mean, is this the typical safety mode?

I would start either with the installer (if that's not you) or with Solis. Solis will have a way to connect to the inverter and check all the settings, check log files on the inverter and tell you if they see anything concerning.

19 hours ago, biometrics said:

Ah ha, worth a try before I replace cables.

Edit: seems it’s not a great idea running it in this mode.

19 hours ago, @zsde said:

Have you tried "USE"(manual user mode for dumb batteries without BMS) mode and set you all your battery parameters manually to see if it then behaves differently?

Perhaps you should start at the beginning (... 🎶 a very good place to start 🎶...). With more (relevant) information, it will be easier for Forum members to make educated guesses and/or suggest fixes to resolve problems:

• Has this problem occurred since the system was installed (when was that?), or is it a more recent problem?

• What made you state "Edit: seems it’s not a great idea running it in this mode."? Presumably you tried that, but something must have happened that changed your mind - Care to elaborate?

  On 2026/04/01 at 12:42 PM, biometrics said:

  After a day without the grid with the battery on the low end it will charge to full at only 180W and that can take a full day.

• This implies that the charging was done at night ("after a day...") Is this assumption correct? If so, there would not be sufficient solar power available to charge the battery, and it would need to be charged with grid power. Is there not a setting on the inverter to select/enable charging from the grid?

1 hour ago, HennieL said:

Perhaps you should start at the beginning (... 🎶 a very good place to start 🎶...). With more (relevant) information, it will be easier for Forum members to make educated guesses and/or suggest fixes to resolve problems:

• Has this problem occurred since the system was installed (when was that?), or is it a more recent problem?

• What made you state "Edit: seems it’s not a great idea running it in this mode."? Presumably you tried that, but something must have happened that changed your mind - Care to elaborate?

• This implies that the charging was done at night ("after a day...") Is this assumption correct? If so, there would not be sufficient solar power available to charge the battery, and it would need to be charged with grid power. Is there not a setting on the inverter to select/enable charging from the grid?

Yes agreed @biometrics give us some measured data, discharge current/ charge current/Soc and overall overview from Solis cloud!!!

On 2026/04/04 at 12:35 PM, HennieL said:

Perhaps you should start at the beginning (... 🎶 a very good place to start 🎶...). With more (relevant) information, it will be easier for Forum members to make educated guesses and/or suggest fixes to resolve problems:

• Has this problem occurred since the system was installed (when was that?), or is it a more recent problem?

• What made you state "Edit: seems it’s not a great idea running it in this mode."? Presumably you tried that, but something must have happened that changed your mind - Care to elaborate?

• This implies that the charging was done at night ("after a day...") Is this assumption correct? If so, there would not be sufficient solar power available to charge the battery, and it would need to be charged with grid power. Is there not a setting on the inverter to select/enable charging from the grid?

• Has this problem occurred since the system was installed (when was that?), or is it a more recent problem?

This inverter was installed about six months ago and since then we went without power twice, once down to nearly 20% SOC and the other time about 40% SOC. Both times it charged slowly and took nearly a day to complete.

• What made you state "Edit: seems it’s not a great idea running it in this mode."? Presumably you tried that, but something must have happened that changed your mind - Care to elaborate?

I asked ChatGPT "What is the consequence if i set my inverter battery settings to manual non BMS mode." and the resulting response made me feel uncertain to try this out. I'd rather explore other possibilities before doing this.

===========================================================================
===========================================================================
===========================================================================

🔧 What changes in non-BMS mode

• The inverter stops receiving real-time data from the battery (state of charge, temperature, cell voltages, etc.)

• It relies entirely on fixed voltage settings you manually configure

• No automatic protection coordination between battery and inverter

---

⚠️ Main consequences

1. Loss of accurate battery monitoring

• State of charge (SOC) becomes estimated, often inaccurate

• Can suddenly drop from e.g. 40% → 0% because voltage-based estimation is crude (especially for lithium)

---

2. Risk of overcharging or undercharging

• With BMS: charging stops exactly when needed

• Without BMS: inverter just follows voltage thresholds

👉 If set incorrectly:

• Overcharge → battery damage, swelling, reduced lifespan

• Over-discharge → permanent capacity loss or shutdown

---

3. Protection becomes one-sided

• Most lithium batteries still have an internal BMS, but:

  • It acts as a last-resort cutoff, not a controller

  • Sudden cutoffs can:

    • Trip your inverter

    • Cause system resets or errors

---

4. Reduced battery lifespan

• Even if it “works,” incorrect voltages or currents can:

  • Stress cells

  • Increase heat

  • Shorten lifespan significantly

---

5. No temperature awareness

• BMS normally prevents charging in unsafe temps

• Manual mode ignores this → risky in very hot or cold conditions

---

🧠 When is manual mode actually OK?

Manual / non-BMS mode can work if:

• You have lead-acid batteries (they don’t use BMS communication)

• OR lithium batteries without communication ports

• AND you correctly set:

  • Bulk/absorb voltage

  • Float voltage

  • Low cutoff voltage

  • Charge current limits

---

🚨 When you should NOT use it

Avoid manual mode if:

• Your lithium battery supports BMS communication (CAN/RS485)

• You’re unsure of the correct voltage settings

• You want maximum lifespan and safety

---

👍 Bottom line

• It won’t immediately break things, but:

• You lose smart protection and accuracy

• The system becomes dependent on correct manual setup

• Mistakes can damage the battery or cause shutdowns

===========================================================================
===========================================================================
===========================================================================

• This implies that the charging was done at night ("after a day...") Is this assumption correct? If so, there would not be sufficient solar power available to charge the battery, and it would need to be charged with grid power. Is there not a setting on the inverter to select/enable charging from the grid?

I don't currently have solar panels, only the battery and inverter.

Edited April 7Apr 7 by biometrics

On 2026/04/04 at 2:31 PM, TaliaB said:

Yes agreed @biometrics give us some measured data, discharge current/ charge current/Soc and overall overview from Solis cloud!!!

Battery Settings (note I have set max discharge to 100A as per the Sunynk spec):

Battery Stats (note max discharge is 0A):

What else can I show you?

On 2026/04/03 at 10:01 PM, Pho3niX90 said:

On the soliscloud app, under device -> battery, see what the amps are registered here.

Is grid charging turned on or off? If off, do you have enough solar to support your house load then charge?

Battery Settings Maximum Discharge is set to 100A, but the battery reports 0A. See above.

I don't currently have solar panels, so I charge from the grid.

4 minutes ago, biometrics said:

Battery Settings Maximum Discharge is set to 100A, but the battery reports 0A. See above.

I don't currently have solar panels, so I charge from the grid.

From the looks of things, the battery isn't requesting a charge, and might be in a floating stage. It might be because it's closer to the 100% SOC (currently 97%), get the battery down to 20%, and charge it back up again. to see what the bms request. This is either a BMS issue, or a comms issue.

PS: In parallel, email solis support as well so that they can check your settings for you remotely. They are extremely helpfull and fast in their responses.

Edited April 7Apr 7 by Pho3niX90

2 minutes ago, Pho3niX90 said:

From the looks of things, the battery isn't requesting a charge, and might be in a floating stage. It might be because it's closer to the 100% SOC (currently 97%), get the battery down to 20%, and charge it back up again. to see what the bms request. This is either a BMS issue, or a comms issue.

PS: In parallel, email solis support as well so that they can check your settings for you remotely. They are extremely helpfull and fast in their responses.

I have been in contact with them, they updated the firmware but it didn't make a difference. I have asked now if they can remotely check it.

This is what it charged at recently:

14 minutes ago, biometrics said:

I have been in contact with them, they updated the firmware but it didn't make a difference. I have asked now if they can remotely check it.

This is what it charged at recently:

Honestly the soliscloud is rather slow. You might be catching it whilst it goes into safety. A direct protocol/modbus test would be the best for this. Or by logging into the BMS's RS485 (unsure what BMS they actually use)

You might have a unbalanced cell, or the battery might be in a safety mode, perhaps turn it off for 10mins for the bms to reset?

40 minutes ago, Pho3niX90 said:

Honestly the soliscloud is rather slow. You might be catching it whilst it goes into safety. A direct protocol/modbus test would be the best for this. Or by logging into the BMS's RS485 (unsure what BMS they actually use)

You might have a unbalanced cell, or the battery might be in a safety mode, perhaps turn it off for 10mins for the bms to reset?

Turned off the battery which stopped power to the house. Had to switch from inverter supply to Eskom supply to get power back. Waited a bit and turned the battery on. After a while the inverter saw it and I could go back from Eskom supply to inverter supply.

It's decided to do a top up, still only 180W:

1 hour ago, biometrics said:

Turned off the battery which stopped power to the house. Had to switch from inverter supply to Eskom supply to get power back. Waited a bit and turned the battery on. After a while the inverter saw it and I could go back from Eskom supply to inverter supply.

It's decided to do a top up, still only 180W:

It's mostly normal to charge 180w at the top end of the %, this avoids accidental overcharging.

Next, cut the grid, drain the battery to 50%, then charge it back up again. See if that helps.

You just need to make sure you haven't accidentally set the grid to max 180w as well.

Edited April 7Apr 7 by Pho3niX90

34 minutes ago, Pho3niX90 said:

It's mostly normal to charge 180w at the top end of the %, this avoids accidental overcharging.

Next, cut the grid, drain the battery to 50%, then charge it back up again. See if that helps.

You just need to make sure you haven't accidentally set the grid to max 180w as well.

Check my photo from three hours ago, 64% SOC and charging at 180W.

6 hours ago, biometrics said:

This inverter was installed about six months ago and since then we went without power twice, once down to nearly 20% SOC and the other time about 40% SOC. Both times it charged slowly and took nearly a day to complete.

I don't currently have solar panels, only the battery and inverter.

Thanks for the feedback - it always helps to have as much relevant information as possible, and your response already sheds more light...

I'm not familiar with the Solis (app or setup), so I quickly downloaded an installation video and a user manual. I always thought that the Sunsynk system settings were frustratingly complex, but I now see that the Solis is at least as complicated, with some really vaguely worded instructions - perhaps it's just the Chinese/English translations... So please keep in mind that the following might be incorrect... Anyway, let's dig a bit deeper:

Have you set the "Quick Settings" and "Self Use Mode" settings for your battery? I could not find any reference to either Sunsynk batteries or Eenovance batteries, so what type of battery did you select in the Quick Settings? (this could be crucial, if the wrong battery/BMS is selected there could be a communication breakdown between the inverter and the battery)If a "non BMS Lithium mode was selected, this could also affect the charging if all the other parameters (Volts, etc) are not set correctly.

In the "Self Use Mode", have you enabled the "Allow Grid Charging" selection? Also, have you entered the "Charge Time Slot" times and "Grid Charging Power" value, and did the times when you expected the batteries to be charged rapidly coincide with a selected time slot?

It might be worth your while to study the manual and setup videos in depth, and to understand all the parameter settings.

1 minute ago, HennieL said:

Thanks for the feedback - it always helps to have as much relevant information as possible, and your response already sheds more light...

I'm not familiar with the Solis (app or setup), so I quickly downloaded an installation video and a user manual. I always thought that the Sunsynk system settings were frustratingly complex, but I now see that the Solis is at least as complicated, with some really vaguely worded instructions - perhaps it's just the Chinese/English translations... So please keep in mind that the following might be incorrect... Anyway, let's dig a bit deeper:

Have you set the "Quick Settings" and "Self Use Mode" settings for your battery? I could not find any reference to either Sunsynk batteries or Eenovance batteries, so what type of battery did you select in the Quick Settings? (this could be crucial, if the wrong battery/BMS is selected there could be a communication breakdown between the inverter and the battery)If a "non BMS Lithium mode was selected, this could also affect the charging if all the other parameters (Volts, etc) are not set correctly.

In the "Self Use Mode", have you enabled the "Allow Grid Charging" selection? Also, have you entered the "Charge Time Slot" times and "Grid Charging Power" value, and did the times when you expected the batteries to be charged rapidly coincide with a selected time slot?

It might be worth your while to study the manual and setup videos in depth, and to understand all the parameter settings.

I selected Lithium LV as instructed by Solis.

4 minutes ago, HennieL said:

In the "Self Use Mode", have you enabled the "Allow Grid Charging" selection? Also, have you entered the "Charge Time Slot" times and "Grid Charging Power" value, and did the times when you expected the batteries to be charged rapidly coincide with a selected time slot?

Here's an example from the manual - if your actual "battery charge" time coincided with a pre-programmed "battery discharge" time, if probably won't charge much...:

33 minutes ago, HennieL said:

Here's an example from the manual - if your actual "battery charge" time coincided with a pre-programmed "battery discharge" time, if probably won't charge much...:

I don't have solar panels but I found this option: Inverter/Inverter Control/Storage Mode/Charge&Discharge Slot and I enabled Slot 1. Let's see if this makes a difference. If this it then it's a pretty well hidden option!