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Topic starter
February 20, 2025 9:47 pm
Hello new user here.
I ran into an issue today and am not sure what is happening. It is single digit temps and the 10 375 watt solar panels were putting out 4K plus watts. 2 strings,4 and six to different mppts. Batteries are charged to 80% + soc by noon and don’t want them to hit 90% to soon because the BMS will limit the charge rate to 10%, which will be 20 amps or 1050 watts or so.
So now need to dump the excess solar. There are 2 resistive heaters with fans at 1500 watts each and two oil filled heaters that can be set to 600, 900, or 1500 watts each. So can control the load pretty easily and use the battery as a buffer to charge and discharge automatically.
Now the load is running 5500 watts and the solar is 4K and the battery is discharging around 1500. Wife turns on the microwave 1500, and it runs 15 seconds or so and the warning 28 comes on and the inverter goes into bypass mode. Now this dumps over 10K watts on the grid and the meter starts a spinning big time. I jump up and start shutting off loads, and after a few minutes the inverter resets. This happens one more time same scenario.
The third time it happened was when the hot water heater came on. It was running along at 7.5K watts for a few minutes and then the warning 28 pops up and by pass again.
I can’t think this is normal. Does this have anything to do with the load factor that has been discussed?
Just putting this out there for what it’s worth.
Lee
This topic was modified 1 month ago by We2
Topic starter
February 22, 2025 8:59 pm
Hello
12000xp updated firmware 405 I believe.
In the local monitor app there is a setting under “Discharge Setting” called “System Discharge Power Rate”. It is set to 10% default.
I have two batteries of the same kind in closed loop with two others paralleled.
The inverter sees two batteries 200AH and 200 discharge capable.
Now if I change the “System Discharge Power Rate” to 20% I’m able to get more watts from my batterie before the warning 28 comes on. Set to 30% and you get more watts again. I was able to run 8K watts load with 3.2K PV and around 5K battery draw steady without a warning 28. If I raised the battery draw another few 100 wattts then the warning 28 would come on. Drop the load back and the warning shuts off.
The inverter is seeing two batteries and adjust the warning accordingly. Since there are four batteries they are not really being overdrawn as they are pulling only half the amps that is being reported to inverter.
It would be dangerous to set this to high as you could set a battery on fire and defeat the by pass function that prevents this from happening.
This makes DIY kind of dangerous without the proper documentation of what these settings do.
I don’t know if my observations are valid or not.
For what it is worth
Lee
Topic starter
February 24, 2025 6:40 pm
Further observations
Had the load up to 7800 watts. The battery was running over 7K watts and no warning 28. So now I’m wondering if this “System Discharge Power Rate“ is for the inverter instead of the battery. Didn’t have time to bump the load over 8K to see if I could get the warning.
Haven’t had time to test the load balance yet. That could still be a possibility, since 4500 watts of the 8K was 120 volt resistive on different plug ins on the first test.
Lee
Topic starter
March 1, 2025 9:44 pm
Thanks Eric
On the Local Monitor App
Under the Discharge setting tab the “Discharge Current Limit(Adc)” is set to 250
Under the Discharge setting tab the “System Discharge Power Rate(%) is now up to 40
I did discover that all the resistive (5000 watts) were on Ln1 and the warning 28 would come on when other heavy loads would come on line. Moved the heaters around to different rooms until the lines were balanced.
Resumed the heavy discharge again at around 8500 watts and the water well pump came on (runs at 1800 watts) this immediately put the inverter into bypass mode. The Lines should have been within 1K or better of each other as I’d just balanced them. The Data on the inverter showed 3 warnings, one of which was before the line balancing. The last two within a few minutes of each other and at the time of the bypass mode. It all happened to fast for me to get any useful data this time. Will keep watching.
It would be nice to know what “System Discharge Power Rate(%)” stands for.
Lee
Topic starter
March 5, 2025 3:30 pm
Hello Eric
First pic is the overview screen on the local monitor app
Second is the local set screen under the discharge setting exspanded
the first line item is the “system discharge power rate (%)”
Thanks
If you need higher res pics I’ll try again.
This post was modified 4 weeks ago by We2
Topic starter
March 6, 2025 4:36 pm
That was my thinking as well. If I push the reset button the default setting is 10%. I’ve been increasing this setting by 10% after the inverter goes into bypass mode. It does seem to increase the power the inverter is able to output before giving the warning 28.
Here is my uneducated theory.
To recap the system is connected to 4 lithium batteries in parallel. There are only 2 batteries that have comms with the inverter in a closed loop configuration. I think this is where all the confusion is happening for the inverter. The closed loop BMS on these two batteries is reporting to the inverter that it can charge at 200 amps and discharge at 200 amps.
A little side bar here: 200 x 51.2 = 10,240 10,240 / 240 volts = 42.6 amps which is below the 50 amp output of the 12000xp.
Since the inverter is able to determine that there is not enough power available it is able to set the (System Discharge Power rate(%) through the firmware to prevent overloading the system.
So here we are trying to figure out a way to overcome his safety limit, since we know there is 4 batteries available to provide the needed power.
i could set the inverter to lead acid batteries, but I really want to use SOC and not voltage. There is no other way to monitor the 2 batteries in the closed loop except the inverter screen. The other 2 batteries have Bluetooth and apps for monitoring.
One of these days I will buy another battery that will be compatible with the closed loop batteries. This would make available 300 amps that the inverter could see and possibly fix the problem as well.
i think this System Discharge Power rate % setting is the work around for my problem. Just don’t have enough information as to what it does to rush to 100% setting thus increasing slowly.
Thanks for the help
Lee
March 6, 2025 8:42 pm
That's very interesting—thank you for sharing!
I also believe setting it to 100% should resolve the issue. There shouldn't be any problems increasing it to 100% all at once, but please let me know if that works for you. Gradually adjusting it, as you mentioned, is also a good option.
Topic starter
March 7, 2025 2:22 pm
Hello
Set the system discharge rate to 100% last night. This morning ran another test. When the load went over 10220 watts the inverter gave the warning and went into bypass. The battery BMS is showing discharge at 199 amps. So as soon as the load went over the BMS discharge limit it gave warning and bypass. Went into the app and checked the system discharge rate setting and it had reset to 10%.
I’m not sure the battery actually went over the limit as there was around 1K PV at the time, but the load had went over the limit. So things are probably working as they should under normal set up.
I guess if loads become an issue I could try the lead acid setting for the battery type or get another compatible battery.
thanks for your help
Lee
