Seplos BMS and RS485 coms to PC

CV350

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I am having problems getting the Seplos BMS to communicate with my PC via the standard RS485 protocol. This is a long story but basically I am on my second BMS ( after seplos admitted the first had a problem) following a successful warranty claim.

Today I spent approximately 4 hours with the Seplos technician trying to get the PC to recognise the BMS (or vice versa). This time was seplos remoting to my pc and trying every combination of the software, three different Rs485 connectors, numerical formats on the software, a different PC, RJ45 cable tests, voltage tests over the connection, different dip switch and Com ports, software refreshes etc etc.

Has anyone else had this problem? I am not feeling comfortable they can fix it. I am fairly certain that it’s a software issue as the hardware side seems ok. The PC has ample capacity is a dedicated server for CCTV and nothing else and it has worked flawlessly.

Feeling a bit flushed as I don’t see light on the horizon and don’t understand how it can possibly be so technical.
 

tigerwillow1

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Hopefully you didn't take as long as I did to realize the baud rate is 19,200. I assume all of your DIP switches are off. Once I set the baud rate correctly mine worked immediately. I've got the impression reading other posts that not all of the seplos BMSs are equal, communication-wise.
 

shavermcspud

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I am having problems getting the Seplos BMS to communicate with my PC via the standard RS485 protocol. This is a long story but basically I am on my second BMS ( after seplos admitted the first had a problem) following a successful warranty claim.

Today I spent approximately 4 hours with the Seplos technician trying to get the PC to recognise the BMS (or vice versa). This time was seplos remoting to my pc and trying every combination of the software, three different Rs485 connectors, numerical formats on the software, a different PC, RJ45 cable tests, voltage tests over the connection, different dip switch and Com ports, software refreshes etc etc.

Has anyone else had this problem? I am not feeling comfortable they can fix it. I am fairly certain that it’s a software issue as the hardware side seems ok. The PC has ample capacity is a dedicated server for CCTV and nothing else and it has worked flawlessly.

Feeling a bit flushed as I don’t see light on the horizon and don’t understand how it can possibly be so technical.
I have probably sold and deployed 120+ of these units in various different amp ratings and bar the diode issue/recall I have never seen a problem at all.
The comms side of things works every time, I use this https://tinyurl.com/4fewc3x8 RS485 adapter, set the baud rate to 19200 n 8 1 and click connect, works every time. I am more inclined to think you have an issue PC side rather than BMS side to be honest
 

CV350

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Hopefully you didn't take as long as I did to realize the baud rate is 19,200. I assume all of your DIP switches are off. Once I set the baud rate correctly mine worked immediately. I've got the impression reading other posts that not all of the seplos BMSs are equal, communication-wise.
Thanks for your response tigerwillow1. Yes I have the baud rate set to 19,200 and the dip switches all off.

Here is a list of what I have done so far:

1. Baud rate is set at 19,200 and I have also tried other rates as well.
2. Dip switches off and have also tried number 1 on.
3. Tried three separate RS485 connectors.
4. Tried orange/ white and orange and separately brown/ brown white wires to RS495 A and B terminals
5. Tried the BMS RS485A and B ports
6. Checked the coms port is set correctly in the software
7. Checked that the Cat6 cable is wired correctly and tests properly - tried a separate cable
8. Checked the voltage (4.9v) in the coms cable is being received at the BMS and the PC end
9. Reinstalled the software several times
10. Restarted the PC and BMS several times

This is the Seplos 16s 200A BMS with Canbus to inverter coms. Seplos supplied the RS485 connector. The PC is a relatively new HP i8 (plenty of capacity and running windows 10 pro).
 

CV350

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I have probably sold and deployed 120+ of these units in various different amp ratings and bar the diode issue/recall I have never seen a problem at all.
The comms side of things works every time, I use this https://tinyurl.com/4fewc3x8 RS485 adapter, set the baud rate to 19200 n 8 1 and click connect, works every time. I am more inclined to think you have an issue PC side rather than BMS side to be honest
That is very interesting shavermcspud.

"set the baud rate to 19200 n 8 1" What do you mean with " n 8 1"?

I agree it is probably a PC issue but I have no idea what it is. When I check the port in device Manager I see that it is working correctly and that I have identified the right port.

I have also made sure that I have a current version of Net Framework installed.
 

CV350

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I see now shavermcspud. This is the existing setting:

USB Serial Port Properties

Bits per second 19,200
Data bits 8
Parity none
Sop bits 1
Flow control None

I have also checked that the numbers and decimal format is correct on my desktop
 

shavermcspud

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I see now shavermcspud. This is the existing setting:

USB Serial Port Properties

Bits per second 19,200
Data bits 8
Parity none
Sop bits 1
Flow control None

I have also checked that the numbers and decimal format is correct on my desktop

Are you 100% sure you cable and pins you are connecting to are correct? send a photo of the RJ45 end pin side up / clip side down and the RS485 end

Also this "8. Checked the voltage (4.9v) in the coms cable is being received at the BMS and the PC end" concerns me, rs485 uses differential signaling, there shouldn't be any fixed voltage on the cable at all for the A & B points.
 

CV350

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Are you 100% sure you cable and pins you are connecting to are correct? send a photo of the RJ45 end pin side up / clip side down and the RS485 end

Also this "8. Checked the voltage (4.9v) in the coms cable is being received at the BMS and the PC end" concerns me, rs485 uses differential signaling, there shouldn't be any fixed voltage on the cable at all for the A & B points
It will be hard to see in that pick but from the r left side first it is 1.Or age white 2. Orange 3. Green white 4. Blue 5. Blue white 6. Green 7. Brown white 8. Brown Exactly the same at the other end.
 

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CV350

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Here is the other end.
 

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shavermcspud

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Here is the other end.
Im not sure what adapter you are using but the cable shouldn't be like that for RS485, photo of the RS485 adapter?
You only need two pins for rs485, you have an Ethernet cable there, you need 7 and 8 (brown/white & brown to B and A respectively
 

CV350

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That’s correct. Depending on what’s on pin 1 and 2 you can also use orange white and orange. I have tried both combinations per the Seplos rs485 wiring guide and that hasn’t solved the problem.

The connectors are all RS485 adapters (see the attached picture - apologies for not providing before per your request. Although the white one is not labelled I purchased it with the BMS direct from Seplos and they sold it as an RS485 adaptor.

Thanks for your help here shavermcspud. Any help or suggestion is welcome.
 

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shavermcspud

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The blue one on the left is what seplos supply, the middle one looks like a USB to Ethernet adapter,
 

CV350

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It’s an interesting point you raise shavermcspud. The white one in the middle is what came with the BMS direct from Seplos. I asked Seplos to supply it in order that I got a compatible convertor. The other two were purchased online.

But now I look at the Seplos website I see that although it says for use with Seplos smart BMS it also clearly states USB convertor. See the attached pic. I will ask Seplos to confirm.

However the other two convertors also don’t make a connection. I have tried orange/ white with Orange and brown/ wire with brown together with the combination of a ground and no ground.
 

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CV350

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It’s an interesting point you raise shavermcspud. The white one in the middle is what came with the BMS direct from Seplos. I asked Seplos to supply it in order that I got a compatible convertor. The other two were purchased online.

But now I look at the Seplos website I see that although it says for use with Seplos smart BMS it also clearly states USB convertor. See the attached pic. I will ask Seplos to confirm.

However the other two convertors also don’t make a connection. I have tried orange/ white with Orange and brown/ wire with brown together with the combination of a ground and no ground.
You were right shavermcspud. Despite making it clear what I wanted, a USB to Ethernet convertor was sent. It follows that most of my testing has also been a waste of time. in the interim I have ordered an additional two RS485 adaptors from the link you sent and I will keep trying to troubleshoot the other two existing RS485 adaptors I have. I am wondering now if it’s a driver problem.

Do you download a specific driver for the adaptor you use or does windows sort it? I see there is mention of the following driver for the adaptor you use (CP210x USB to UART Bridge VCP Drivers" and select the Silicon Labs result).

thanks for the direction.
 

houseofancients

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You were right shavermcspud. Despite making it clear what I wanted, a USB to Ethernet convertor was sent. It follows that most of my testing has also been a waste of time. in the interim I have ordered an additional two RS485 adaptors from the link you sent and I will keep trying to troubleshoot the other two existing RS485 adaptors I have. I am wondering now if it’s a driver problem.

Do you download a specific driver for the adaptor you use or does windows sort it? I see there is mention of the following driver for the adaptor you use (CP210x USB to UART Bridge VCP Drivers" and select the Silicon Labs result).

thanks for the direction.
for me , windows picked the driver up by itself
 

shavermcspud

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You were right shavermcspud. Despite making it clear what I wanted, a USB to Ethernet convertor was sent. It follows that most of my testing has also been a waste of time. in the interim I have ordered an additional two RS485 adaptors from the link you sent and I will keep trying to troubleshoot the other two existing RS485 adaptors I have. I am wondering now if it’s a driver problem.

Do you download a specific driver for the adaptor you use or does windows sort it? I see there is mention of the following driver for the adaptor you use (CP210x USB to UART Bridge VCP Drivers" and select the Silicon Labs result).

thanks for the direction.

The chances are, if you have connected up the adapter and it is a "USB to Ethernet adapter" to the RS485 port on the BMS it will have damaged it permanently, the brown & brown/ white have a 7v+ initial bias + & - on initial connection to determine if a POE switch is connected, this will destroy the BMS's RS485 instantly, hence why you possibly have had no luck on using any of the other adapters if it is indeed an Ethernet adapter?. Although looking at the spec, the white unit appears to be an FTDI USB to RS232 serial port which again is bad news if connected up, RS232 & RS485 are two very different transport layers for communication with different voltages etc. Their website doesn't make it clear what BMS uses what interface, although every unit I have bought and requested an RS485 adapter with has come with the blue USB unit. I'm going to go out on a limb here and say the unit is damaged now. I presume you are in the UK like me? Drop me a private message, if you are local to me, we can do some test on kit I have here.
 

tigerwillow1

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Here's some info if it could help with debugging. In the picture of the 3 converters, the green/black Waveshare one on the right is what I'm using. When running, the power LED is on constantly, and the TxD/RxD LEDs blink. Device driver is FTDI FT232R version 2.12.36.4 . If I bring up the Seplos battery monitor program without the RS485 line connected, the converter's power LED is on solid and the TxD LED blinks briefly at about 7 second intervals. If yours does this I'd assume that the software is talking to the converter OK. With the RS485 line not connected, the voltage between the A and B converter lines is zero, and about 2.6 from either converter line to the ground connection. When the converter is connected to the battery, the voltages are roughly the same, except for small differences between A and B when data is transferring.
 

CV350

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The chances are, if you have connected up the adapter and it is a "USB to Ethernet adapter" to the RS485 port on the BMS it will have damaged it permanently, the brown & brown/ white have a 7v+ initial bias + & - on initial connection to determine if a POE switch is connected, this will destroy the BMS's RS485 instantly, hence why you possibly have had no luck on using any of the other adapters if it is indeed an Ethernet adapter?. Although looking at the spec, the white unit appears to be an FTDI USB to RS232 serial port which again is bad news if connected up, RS232 & RS485 are two very different transport layers for communication with different voltages etc. Their website doesn't make it clear what BMS uses what interface, although every unit I have bought and requested an RS485 adapter with has come with the blue USB unit. I'm going to go out on a limb here and say the unit is damaged now. I presume you are in the UK like me? Drop me a private message, if you are local to me, we can do some test on kit I have here.
I agree with you that there is possible damage to the BMS caused by connecting the USB to Ethernet adaptor. I don’t know much about RS485 and how it works but I have exhausted nearly every other option and this should be simple plug and play. Seplos however are adamant that the USB to Ethernet connection won’t cause a problem and in their words “never has in the past”. What you say makes sense to me. Unfortunately I am in Thailand or I would take you up on your offer to test the unit. That was very generous of you.

The only other thing that I can think of is that maybe my adaptor is not compatible with my operating system (which is Windows 10 pro) but I will need to wait to try another adaptor before I can test that possibility. However when I check the coms port on device manager it says it’s installed and operating properly. Thanks for your help.
 

CV350

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Here's some info if it could help with debugging. In the picture of the 3 converters, the green/black Waveshare one on the right is what I'm using. When running, the power LED is on constantly, and the TxD/RxD LEDs blink. Device driver is FTDI FT232R version 2.12.36.4 . If I bring up the Seplos battery monitor program without the RS485 line connected, the converter's power LED is on solid and the TxD LED blinks briefly at about 7 second intervals. If yours does this I'd assume that the software is talking to the converter OK. With the RS485 line not connected, the voltage between the A and B converter lines is zero, and about 2.6 from either converter line to the ground connection. When the converter is connected to the battery, the voltages are roughly the same, except for small differences between A and B when data is transferring.

Thanks tigerwillow1. When I plug the device in I get a momentary light up of all lights and thereafter just the solid power light. The TXD light flashes faintly about every 7 seconds when the software is open but nothing from the RXD light. When the monitoring software is open and the device is connected to the PC the voltage on both A and B is around 2.6v and virtually nothing between A and B.

What operating system are you using with the Waveshare?
 
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