I have a combination of AC200L and B300K set up to charge from solar. Additionally I have connected an AC load that draws 170W constantly. So, when Solar Input exceeds AC load I expect the SoC to climb. That does not happen. The SoC constantly dropped to lower levels despite the solar input has a lot of power going in. Example: I had a power input of 278W over the last 3h. I also had an AC load of 170W over the last 3h. The difference of 108W should have been enough to at least stop the SoC from dropping or even contribute a bit to charge the batteries. In my case the SoC dropped around 7% The individual batteries had a drop of 8% (AC200L) and 8% (B300K). To my understanding this should not have happened in this amount.
Hi @ftrueck, According to your description, the AC200L + B300K indeed experiences relatively fast power drain.
When the AC200L has AC output enabled, its self-power consumption is 18W per hour, while the B300K has a 5W self-power consumption when there is a load.
Apart from the impact of self-power consumption, we would like to know whether the ambient temperature is suitable and whether you have upgraded all firmware to the latest version.
We recommend that after upgrading the firmware, you recalibrate the device and then test again. Do you think this could be helpful?
Hi @BLUETTI_CARE,
Thank you for the reply.
Firmware is uptodate.
Ambient temperature was moving between 22°C and 29°C at any time. Never above.
Today I completely drained the system with a load of 1.1KW and any power input disconnected until the AC cut of and the AC200 beeped.
Then I replugged all power inputs (solar + AC) and let it charge with 980W AC and around 200W solar to 100%. After that I reconnected my AC load and let it run normally. The only thing I changed was the SoC limits in the custom UPS settings. Before the upper SoC level was up to 80%. Now I have set it to 100%. I read a side note that the AC200L can keep discharging for load compensation under certain circumstances.
I have to admit I didn’t understand that fully but maybe I had this case. For the moment it seem that something has improved but I can not tell at the moment. I will have to see tomorrow how the system behaves under my usual conditions with solar charging during the daylight.
Hi @ftrueck, Thank you for providing the detailed information.
Yes, when you notice fast discharging, upgrading the BMS and recalibrating can be very helpful.
We hope this addresses the issue. Looking forward to your test results.
@BLUETTI_CARE i did some testing. Basically the recalibration did something. The balancing is now not so far off anymore. However: the discharge is still a thing.
I attached my monitoring chart for comparison.
At around 10pm I start charging to around 90% which is reached at 03:40 am. At 6 am the charging window closes so the SoC is falling again. At around 8am the sun is kicking in and you can clearly see a flattening of the discharge which bottoms out at around 62% until another charge window opens at 2:30 pm until 4pm.
Basically: The solar input only stops the SoC to fall below 62% which is not bad.
But: the max power input was around 275W as you can see in the chart above.
The power draw from AC output was pretty constant with very tiny peaks that should not matter further.
If I do a rough math: 275W - 175W = 100W. If the net consumption of AC200L + B300k is 18W + 5W = 23W there is still a gap of 77W which seems to have no effect at all. At least not from what I can observe so far. I would expect that the SoC at least climbs 1% within 6h of sunlight but so far there is only a bottom out. Maybe the MPPT circuit has a bigger loss than 9%?
Hi @ftrueck, Thank you for the update.
From the screenshots you provided, the solar input power seems unstable. Could this be one of the causes?
If you use AC charging, will the test results be different?
Hi @BLUETTI_CARE,
since I live in Germany it is quite normal that solar input is unstable. We often get clouds in the south west. With charging window I meant AC input. I can not charge with solar alone at the moment. But: even when solar input is constant the difference of 100W is not enough to charge the battery. It seems that there is a loss that is unknown. AC charging is stable. I should check how the battery behaves when I charge with 1A only.
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Edit: I have configured the AC200L to pass through AC power and use the solar input to charge the battery.
In this configuration the battery charges. Even with as low as 40W input the battery SoC increases, so the Solar path seems to be ok. It seems the Path Battery to AC converter is using more energy than expected. Probably the efficiency is below the specs?
Hi @ftrueck, Thank you for the update. It’s great to hear that after setting the PV input correctly, the SOC successfully increased during solar charging.
We haven’t specifically tested the power input behavior under incorrect settings, but we do strongly recommend users select the correct input mode based on their actual power source.
@BLUETTI_CARE there is no incorrect settings.
Your app provides the settings. I am setting them. Nothing incorrect here.
If your custom UPS settings are not working the way they were designed it can not be the fault of the user but of the designer.
What I want is:
- Running the AC200L in autonomous mode as much as posible
- Use solar as main energy source as much as possible
- Charge in low tarif hours if needed
- Run in passthrough mode if SoC below 20%
How i configured Custom UPS settings:
- SoC Setting: 20% - 90%
- Charge from Grid: yes
- Use Time Schedule: yes
- Time schedule: 00:00 - 06:00 Charge, 06:00 - 14:30 Discharge, 14:30 - 16:00 Charge, 16:00 - 22:00 Discharge, 22:00 - 00:00 Charge
So far these settings were working as intended with the exception that the PV input during sun light is not contributing to the SoC as it should, instead the SoC drains continously despice PV Input > AC Output.
Hi @ftrueck, We’re indeed aware of the recent issue where the customized UPS settings are not functioning as intended. We’ve already developed a new version of the app to fix this problem.
The updated app has been submitted for review, but we still need to wait for the platform’s approval. While we’re not certain how long that will take, it shouldn’t be too long.
We recommend waiting for the new version to be released, then updating the app and testing again. Thank you for your understanding and patience.
@BLUETTI_CARE, it also would help to have some sort of documentation how the custom UPS mode is operating. For example: I found out that the AC inverter is using the grid for synchronization all time even if there is no grid usage. These kind of information would be very helpful to understand what can be set and what not.
Hi @ftrueck, I agree with your opinion—providing more guidance documents about UPS would definitely be more helpful.
At the moment, we only have the user manual to explain how the UPS mode operates. We’ve also passed your suggestion on to the technical team, and we hope they’ll be able to complete this work in the future.
Hi @ftrueck, Regarding the issue you’re encountering, our testing department plans to reproduce it.
Could you please let us know the specific loads you’re using and their respective power ratings?
Additionally, we’d like to know the current firmware version of your AC200L. Then we’ll proceed with the testing.
Hi @ftrueck, We’ve analyzed the issue and found that the PV charging time window you set is not ideal.
Here is your setting:
Charge from Grid: yes
Use Time Schedule: yes
Time schedule: 00:00 - 06:00 Charge,
06:00 - 14:30 Discharge,
14:30 - 16:00 Charge,
16:00 - 22:00 Discharge,
22:00 - 00:00 Charge
Sunlight is most abundant between 06:00–18:00, so this period should be set for charging. However, you’ve scheduled discharging during 06:00–14:30, which is not reasonable.
Alternatively, you can skip setting a charging time window. Instead, select “PV Priority” and turn off “Charge from Grid”—this way, it won’t draw power from the grid. The system will automatically start PV charging when sunlight is sufficient during the day and stop PV charging at night (when there’s no sunlight) to switch to discharging. Setting a fixed charging time actually limits the system’s ability to automatically initiate PV charging.
So, charge / discharge schedule setting not only affects grid usage but also PV? Why should I want to schedule PV charging??? PV is there permanently and if the sun is shining the energy should be used for charging the battery. Why should I want to disable charging the battery from PV? That is not intuitive. My assumption was that the time schedule only affects the Grid usage. This way PV would have been used all time and grid only during scheduled times. The way you described it the custom UPS mode is completely useless. My settings would resemble this idea: Since my current PV setup (400W) is not enough to charge the battery during sunlight fully (160W permanent load) I want to recharge during night hours to fill up to 100% since energy is cheap during night time. During the day the PV would mage the battery drain slower as it supports the load. Additionally in peak hours when PV input reaches 400W the battery could charge from excess energy.