Renogy Battery Error 04 Battery Over-Voltage Protection / Battery Cell Over-Voltage Protection when MPPT entering Boost Mode

[TheGoldenPanda]

I am seeing an error on my Renogy Lithium batteries (two 100 Amh) while the MPTT (Renogy Rover Li 20A) entering the boost mode.
The error code is 04 Battery Over-Voltage Protection / Battery Cell Over-Voltage Protection. The boost voltage on the MPTT is currently set to 14.4 (the default Li-battery settings). According to the spec from Renogy, battery overvoltage protection is triggered when the battery is >= 14.8 volt, and the battery cell over-voltage protection is triggered when the battery cell voltage is >= 3.7 volt. From the reading, I have not exceeded either.
Any idea or suggestion on what is the right boost voltage in the MPTT? (My solar is 255W panel with Operating Voltage 30.2, operating current 8.43).

 

[flammafeuer]

Did you find an answer, your issue is extremely similar to mine (240 W panel, Li battery, Voc ~38 Vdc, Imax ~8 A). I get errors as different controllers get the battery is close to being full, contrary to your issue.

 

[acdoctor]

How do you know you didn’t hit 3.7 volts on a cell? Do you have the ability to monitor your batteries at the cell level?
I suspect you have hit cell over voltage. Cells a couple of tenths out of balance can cause this.
I would try backing the bulk charging voltage down a little. And make the Absorb ( boost ) the same for ten or twenty cycles. The BMS should balance the cells but it may take some time. Most BMS don’t balance very fast. If you can control the charge amps try reducing amperage from 3.45 volts per cell (13.8 volts for the battery) and above to give the BMS some time to lower the high cell.

 

[flammafeuer]

First, thanks very much for thoughts on how to troubleshoot this.

I don't have the ability to monitor the batteries at the cell level. Frankly, I'm new, and while I have seen the curves and charging modes, I don't know how they line up with the settings on my controller. The HQST has a Li mode where you can set the battery system voltage (12/24), the charging voltage (which I set to 14.4 to match the battery), the over-discharge recovery voltage, and the over-discharge voltage. I haven't messed with the last 2. There is a User setting, and one can change the system voltage, the Equalize voltage, the Boost voltage, the Float charge voltage, the equalize charge interval, and then the same over-discharge settings from the Li mode.

Which of these corresponds to what you are calling "bulk charge"? I don't think I can change the interval like you mentioned, and I'll have to look at the Equalize Charge Interval, which seems to have units in "d", which I assume is "days". Any thoughts how I can translate your suggestions to these settings?

I don't quite understand how the battery voltage and exceed the controller limit (see attached E02 error message). Does this mean controller is delivering a higher voltage than the battery is supposed to be exposed to, or that the controller is sensing a battery voltage higher than some controller setting or parameter?

How do you know you didn’t hit 3.7 volts on a cell? Do you have the ability to monitor your batteries at the cell level?
I suspect you have hit cell over voltage. Cells a couple of tenths out of balance can cause this.
I would try backing the bulk charging voltage down a little. And make the Absorb ( boost ) the same for ten or twenty cycles. The BMS should balance the cells but it may take some time. Most BMS don’t balance very fast. If you can control the charge amps try reducing amperage from 3.45 volts per cell (13.8 volts for the battery) and above to give the BMS some time to lower the high cell.

 

[OneStudPuppy]

I am seeing an error on my Renogy Lithium batteries (two 100 Amh) while the MPTT (Renogy Rover Li 20A) entering the boost mode.
The error code is 04 Battery Over-Voltage Protection / Battery Cell Over-Voltage Protection. The boost voltage on the MPTT is currently set to 14.4 (the default Li-battery settings). According to the spec from Renogy, battery overvoltage protection is triggered when the battery is >= 14.8 volt, and the battery cell over-voltage protection is triggered when the battery cell voltage is >= 3.7 volt. From the reading, I have not exceeded either.
Any idea or suggestion on what is the right boost voltage in the MPTT? (My solar is 255W panel with Operating Voltage 30.2, operating current 8.43).

Sounds similar except I ended up with a e02 and e04. Mine was the wanderer 10a, 100 watts and ampere time 100ah battery. Was the 2nd problem the controller gave. As of now I’ve pulled it out of service and am now looking for a controller with custom user profiles / voltage can choose the numbers instead of a pre set up fixed profile.
I’ll follow along on your solution. But I’m kinda done renogy controller wise

 

[flammafeuer]

I started with a Wanderer 10A (PWM), then moved to an HQST 40A (MPPT). I got over-voltage protection errors on both with the battery's suggested Charge voltage used as the Boost setting on these controllers. On the HQST, I've been using the Bluetooth app to slowly reduce the Boost voltage, and this has slowed down how soon E02 (over voltage) shows up. right now I'm at 14.0 Vdc on Boost for my Weize 50 Ah LFP battery, and waiting to see if an error shows up.