Hi,

How do I start the BMS up again after it has reached the 48V low voltage cutoff?

 

The inverter cut off was set too low, and the BMS switched of at 48V.  Now, when I turn the BMS off, and back on, the start up sequence occurs, and then ALARM LED comes on to show the low voltage condition, but the BMS does not switch on to allow the inverter to charge it again.

 

Should I just use the receded RESET pin on the front panel of the BMS to reset the unit?

https://revov.co.za/2ndlife/revov-2nd-life-r9-lithium-iron-battery/

I cant provide info to solve your problem but do you perhaps know what the BMS make is?

PACE BMS. What frustrates me is the limited documentation I can find on my battery type and BMS on the supplier website. I have no idea from the official info what the cut off voltage is. I've set my inverter to go back to grid at 51V up from 49V until I can work out what's going on.

My inverter can also not interrogate the BMS for SOC, and the highest my inverter cut off can be set to is 48V.

The BMS switched on again, but that was not a great experience.

5-REVOV-R9_220Ah_SpecV3.pdf

Edited August 9, 20232 yr by lcj

What I have found is from Segen, where they give the spec of the battery cut off voltage of 48V?

When the BMS cut out the voltage of the battery was sitting at around 48.6V, so the BMS already determined SOC was too low and switched off.

I'm working on adding a monitor to the BMS to record the BMS details, I'm case this happens again. Want to ideally have my inverter talk to the BMS directly, but KODAK is not yet able to do this.

Here's a link I found which looks like your battery, it seems to have the same specs... it suggests a battery cutoff of 50-49.5V.

https://revov.co.za/wp-content/uploads/2020/05/Specs-and-recommended-settings-by-REVOV.pdf

 

There is a toolset that allows one to interrogate the BMS, pretty much the Pylontech batteryview equivalent.

I will find the app and upload a link to it if anybody wants it..

So, I was able to read out the settings I'm interested in and found it to be what I was expecting.  Now it begs the question why is the BMS cutting out before reaching the UV alarm setting.

From my understanding it looks as if the BMS might be reaching 0% SOC before reaching the UV setting and then switches off.  I'll be monitoring it to understand the scenario under which is occurs.  For now I have moved the inverter setting for back to grid up to 51V to avoid the same scenario of a BMS that has switched off.

The software is available from the following website:  https://shop.thesunpays.co.za/pages/technical-support  .  My suggestion if you are looking for the PBMSTool is to search for it and download the relevant version applicable to your Pace BMS.

16 minutes ago, lcj said:

Now it begs the question why is the BMS cutting out before reaching the UV alarm setting.

Could it be possible that it might be switching off due to a cell undervoltage protection? Being a second life battery the cell voltages might sag unevenly under load which might be why the document I found suggests a low voltage of 49.5V and not 48V.

6 minutes ago, jumper said:

Could it be possible that it might be switching off due to a cell undervoltage protection? Being a second life battery the cell voltages might sag unevenly under load which might be why the document I found suggests a low voltage of 49.5V and not 48V.

Thanks for the suggestion.  I'm going to try and let the pack run down and monitor the cell voltages.

Does anyone know which port to use and what the pinouts are to link Pbms tool to the pace bms (revov R9 set )

Hi @Peter Burden ,

Easiest is to use a USB to RS232 cable (from solar-assistant.io or elsewhere), and plug it into the RS232 port on the battery.

then just install PBMSTools on PC, open app and configure the Comms port settings.

I believe there are versions of PBMBSTools that work only on RS485 port + USB to RS485 cable, but I have not verified that myself.

If anybody can verify if this is the case, please add comments.

I'd urge caution with this. You may void your warranty by using PBMSTools, and I know from experience that Revov monitor this forum.