Seplos BMS

@Clf , I disabled backup mode but the battery continued to operate as previous, not going in to standby, so I guess that is how it should be operating.

One thing I have noticed is that I am getting OV_ILLC alarm just when the battery is doing final charge to 100pc and voltage goes over 56v. Is this something I should be concerned on? The alarm resets after about 30 mins. Thanks for all the help

I have a v2.0, I believe that maps to 10E?. The firmware version is 3E0039 so a little older than yours. I see in page 28 of this thread some contributors have made the same observation that the battery is continuously exporting a trickle KW amount. Really it is not an issue for me, I just want to ensure that charging batteries to 100% will not overly impact life of product and avoid the OV-ILLC error. For a test I reduce the overvoltage to 57V last night, trying to keep BMS voltage below 56.5V which going above seemed to trigger OV-ILLC alarm (66.7V peak on alarm), and with just this change the BMS actually does go to sleep and I had to use the reset button to get it working again this morning. Very hard to understand the control logic between the Inverter and BMS.

Just hooked up my 2 seplos battery packs to my sunsynk inverter and now I can only connect to the "slave" battery using battery monitor. I can't get any connection to the master battery any longer. Only thing that's changed is that the master battery is now connected to the inverter through the CAN port but battery monitor uses the RS485 ports. What am I doing wrong?

Oh how bizarre! At least it's not something I've done.......

Anybody know what this error message means? It appeared after a cell over voltage protection shut down when charging.

Not sure what you're trying to say....."switch the pack light" ??

I can connect to each pack but they have this error message. Do you know what it means and how I can get rid of it?

As I said in my earlier post, you can't connect to both packs when you have the master connected to the inverter on CAN and bluetooth is not an option.

Anyway, my issue is the error message

Intermittent power supply comes on when the BMS hits 96% is about the mos tube turns it's self on and off.

This is really weird, but hopefully in a good way!

After having to disconnect comms cables from inverter and battery to sort out RS485 connections, now everything is reconnected I have the master battery BMS communicating with the inverter but I can now also connect to BOTH battery packs in Battery Monitor.

I'm not sure why this now works but I have a suspicion it is to do with the CAN connection on the battery. Previously all 8 pins were connected between inverter and master battery CAN/RS485 connection. Since I needed to make up a cable to split out the RS485 pins from the inverter, only the CAN pins 4/5 are connected to the battery, and none of the other pins.

I'm thinking that with the battery not sensing any RS485 connection on the dual CAN/RS485 port it doesn't then disable comms with the master battery and allows master and any slave batteries to be seen in battery monitor via the standard RS485 ports. Not sure if this is a bug in the firmware or an unintended consequence. Hopefully the latter.

Certainly makes it far easier to monitor and reconfigure any BMS settings without having to constantly haul myself up and down the loft ladder to swap cables about between batteries.

Hope that helps others having similar frustrations with battery monitor and multiple battery packs.

Interesting. So on the SEPLOS End, the cable towards the inverter is just using pins 4 & 5 (on the RJ45) ?

Thats how i have it setup also. Split out the CAN H&L lines and RS485 from the CAN port, i have the H&L lines diverted to a CAN hat on a raspberry pi to read out the comms to the inverter, useful for problem solving. With a Solis inverter you can use Waveshare RS485 to ETH devices to read data from each BMS and maintain the cloud stick.

Seplos BMS v2 Charging Current Restricted to 100A

I have one of my Seplos battery packs connected to my Sunsynk 8kW inverter but even though I set the inverter to charge at 150A (0.5C on a 304Ah pack) it seems like the BMS is restricting the actual charge to only 100A according to the BMS page on the inverter.

I've looked at the BMS settings but can't see anything which suggests this current limit is changeable so don't know why a 200A BMS is restricting the charge current. The only thing I did see was that there is a function switch in battery monitor for setting "Single BMS 1.0C Charging" but worried that it's the wrong thing to switch on.

Any thoughts?

Do you know which parameter number is the one i need to change?

@garo It has been about 3 weeks or so since I got the firmware update and applied the recommendations proposed by yourself and @Clf and everything is working perfectly. Since updates I was able to reduce over voltage to 57v in inverter and I no longer see the spike. Very happy with how it is working and thanks to you and @Clf for the help.

I am not getting shading on some of my panels for the last week or so now that the sun is low. Now investigating if it is worth getting optimizes or not for those panels 😊

That is what I taught. I taught I would have little to worry about but for example yesterday, a cold but beautiful sunny day, once the shading was hitting the panels I was only getting as low as 200Ws on a 10x420W array. I have photos of the shading and output from the solis cloud that can be overlayed to show the corresponding drop with the shading. I wonder is there anywhere more suitable I could post the pictures to discuss further. I am conscious that this thread is for Seplos BMSs and not for shading issues :).

Now I have my two Seplos batteries hooked up to my Sunsynk 8kW inverter and have done the charge/discharge cycle to calibrate the capacity, to maintain battery condition I'm going to use a charge rate of around 0.5C but also want to limit the minimum/maximum SOC levels to avoid the "knee" at either end of the cell charge/discharge curve.

What would be the ideal settings to use in the BMS/Inverter? Is it just a simple case of setting inverter limits to say a range of 15-95% or should I aim for something slightly lower? If I set the %SOC in the inverter do I then just leave the BMS settings as the defaults?

I understand that the v3 active balancer is a seperate element and not automatically included with the BMS so make sure you also specify the active balancer when you order the BMS.

I'm totally confused. Would anyone know the DIP Switch settings to get 4 280Ah battery packs connected?

Many thanks

Thank you for such a quick response!

I have one more question. 2 of the battery packs are the old BMS 10 C type and 2 are the new Bluetooth BMS 10 E, is it OK to parallel this type of combination?

Many thanks again.