Victron VenusOS driver for serial connected BMS - LLT/JBD / Daly Smart / ANT / JKBMS / Heltec / Renogy

Louisvdw

Solar Enthusiast
Joined
Dec 18, 2020
Messages
93
PS. Also see this thread. It's a bit long, but you will see many comparisons on a system running both BMS and BMV and which one should be used. In that system some of the cells did get hurt cause the BMV's SOC was believed above the BMS's.
 

jamiegreen

New Member
Joined
Nov 8, 2021
Messages
67
PS. Also see this thread. It's a bit long, but you will see many comparisons on a system running both BMS and BMV and which one should be used. In that system some of the cells did get hurt cause the BMV's SOC was believed above the BMS's.
Thank you very much for all the info, when I finally get round to putting everything together I'll upload the firmware to the ccgx and see how I get on with the JK BMS, haven't used one before but seems to tick all the boxes.
 

Martijn

Solar Enthusiast
Joined
May 6, 2021
Messages
141
Oh, this is very very interesting!

However, I'm confused as to what cable I should use for a JK BMS to connect to my MultiPlus II? Any pointers?
 

Louisvdw

Solar Enthusiast
Joined
Dec 18, 2020
Messages
93
However, I'm confused as to what cable I should use for a JK BMS to connect to my MultiPlus II? Any pointers?

You get a RS485 cable for the JKBMS like in the picture, and then use a RS485 to USB converter (FTDI works well) that you plug into your GX device.
1637250934808.png
It is very likely that this box is a TTL to RS485 converter, so then you can use a TTL to USB directly as well, but I have not tested that.
 

Horsefly

Photon Sorcerer
Joined
Dec 12, 2020
Messages
1,027
Location
Denver, mostly
I have a question, and the answer may be somewhere in the 7 pages of posts, but I didn't see it.

I'm helping someone upgrade their sailboat system. He's buying a bunch of Victron stuff, including the Cerbo GX an GX touch. I'm putting together two 4S 280Ah batteries that will be in parallel (4S2P). Each 4S battery has a JBD 150A 4S BMS with a Bluetooth. The BMS's seem to have a pads for a RS485 interface, but no header there to plug into. I don't know if that means the rest of the RS485 interface is not really there.

I know nothing about VenusOS, but I get the impression it is Linux based. Is it what runs inside the Cerbo GX? If so, is it possible to use this driver and get info from the two BMS's into the Cerbo GX and available on the GX Touch?
 

jamiegreen

New Member
Joined
Nov 8, 2021
Messages
67
You get a RS485 cable for the JKBMS like in the picture, and then use a RS485 to USB converter (FTDI works well) that you plug into your GX device.
View attachment 72695
It is very likely that this box is a TTL to RS485 converter, so then you can use a TTL to USB directly as well, but I have not tested that.
Didn't think of that.. how to connect it.. guessing that's something that can only be bought from China through the JK store, unless I give the generic one a try and report back.
 

Louisvdw

Solar Enthusiast
Joined
Dec 18, 2020
Messages
93
is it possible to use this driver and get info from the two BMS's into the Cerbo GX and available on the GX Touch
All the GX devices run on VenusOS (yes embedded Linux based system)
You will be able to use this driver to connect those JBD BMS to the GX, but if the RS485 port is not there (normally an extra addon when you order it), then you will have to use the UART that the bluetooth is connected on (so unplugging that after your set up with bluetooth is complete)
The driver does not yet support multiple banks, so you will only see the detail of the one BMS on the GX Touch, but in the detail of the GX both batteries will be there.

Click the link in my footer and go to the wiki to see how to install the driver.
 

Louisvdw

Solar Enthusiast
Joined
Dec 18, 2020
Messages
93
China through the JK store, unless I give the generic one a try
I got mine through the JK store yes, but it plug into the port labeled GPS/RS485, so give the generic a try and let me know so I can update the docs if it does work.
 

Martijn

Solar Enthusiast
Joined
May 6, 2021
Messages
141
Last edited:

Louisvdw

Solar Enthusiast
Joined
Dec 18, 2020
Messages
93
But the USB-connector has only 2 slots for wires, while the RS485 has 4 wires?

You probably know of this makes sense but I'm puzzled ;)

The RS485 cable in that link will have 3 wires. Ground (black) and A &B (white and yellow)
Your USB connector will also have a ground that you connect the black wire too, and then A & B for the data lines.
 

Martijn

Solar Enthusiast
Joined
May 6, 2021
Messages
141
The RS485 cable in that link will have 3 wires. Ground (black) and A &B (white and yellow)
Your USB connector will also have a ground that you connect the black wire too, and then A & B for the data lines.
Right, 3 wires, my bad.

From the link above by @jamiegreen - this looks like 2 connections?
1637307299886.png
 

Martijn

Solar Enthusiast
Joined
May 6, 2021
Messages
141
Here's another, with 3 connections.
1637307498285.png

On AliExpress I can find several with 5 connections: 2 signal, 2 GND + 1 x 5V, guess you can use only 1 GND and leave the 5V disconnected?
 
Last edited:

jamiegreen

New Member
Joined
Nov 8, 2021
Messages
67
So, that, in combination with this

But the USB-connector has only 2 slots for wires, while the RS485 has 4 wires?

You probably know of this makes sense but I'm puzzled ;)
No need for the JK official dongle, thats what I'm trying to avoid, the link I posted essentially does the same thing.. (we think). It's just a basic little device that converts one signal to another. The JK BMS has 4 wires because 2 of them are +voltage (battery voltage) and ground, whereas the converter I posted takes its power from the USB so there's no need for the other 2 pins, only the 2 signal cables.
 

Martijn

Solar Enthusiast
Joined
May 6, 2021
Messages
141
No need for the JK official dongle, thats what I'm trying to avoid, the link I posted essentially does the same thing.. (we think). It's just a basic little device that converts one signal to another. The JK BMS has 4 wires because 2 of them are +voltage (battery voltage) and ground, whereas the converter I posted takes its power from the USB so there's no need for the other 2 pins, only the 2 signal cables.
So the official JK module has 3 wires that go to the GX Device, you intend to use 2, the data wires only? But you would still need to have a tiny connector on the BMS side, right? And you expect the USB port converter to accept the data wires from the BMS?

The JK module has more wires on the BMS sides, but these are meant to power the module? What does the module do then?
 

Louisvdw

Solar Enthusiast
Joined
Dec 18, 2020
Messages
93
From the link above by @jamiegreen - this looks like 2 connections?
Ah OK I see. Yes in that case you will wire up only the A & B data lines, but the 3wire models that has aground is much better. Like the Waveshare model you posted.
RS485 comms work on the difference between A & B for the data signal, so it could work with only 2 wires. But the ground connection makes it stable and reduce interference so I would suggest using those dongles.

What ever you do, do not connect the red V+ power from the BMS and the USB dongle.
Those are only used for isolated wires that need power from both ends. (Like Victron official cables)
 

jamiegreen

New Member
Joined
Nov 8, 2021
Messages
67
So the official JK module has 3 wires that go to the GX Device, you intend to use 2, the data wires only? But you would still need to have a tiny connector on the BMS side, right? And you expect the USB port converter to accept the data wires from the BMS?

The JK module has more wires on the BMS sides, but these are meant to power the module? What does the module do then?
I haven't looked much into the JK converter, I'll assume the 3rd wire is a ground. The one I posted does not connect the ground from the USB to the BMS, I don't think this would matter, maybe someone could confirm, either way it would share a ground somewhere else in the system.
Yes I would still need a "tiny connector" on the BMS side, this looks like a standard PCB style molex socket.
Yes the USB dongle will accept the signal straight from the BMS (although untested yet) that is essentially what it's designed to do, and very likely the same as what's inside the JK converter..

The only difference I see with the JK converter is, it looks like it takes its power from the BMS rather than the output, I think this would mean full battery voltage so probably has some sort of step down converter inside.
Screenshot_2021-11-19-07-46-16-414_com.google.android.googlequicksearchbox.jpg
 

Louisvdw

Solar Enthusiast
Joined
Dec 18, 2020
Messages
93
The JK converter is most likely an isolation device. This is a safety device that makes sure the power from the battery has no way to get the the RS485 bus and on to your PC/GX. Most isolation devices use a opto chip. Essentially a man on either side of the river showing flags to the guy on the other bank, and that man talks on the phone to relay the message.
If they use different voltage then they cannot hurt each other.
It's the same reason you don't connect the V+
 

Martijn

Solar Enthusiast
Joined
May 6, 2021
Messages
141
I haven't looked much into the JK converter, I'll assume the 3rd wire is a ground. The one I posted does not connect the ground from the USB to the BMS, I don't think this would matter, maybe someone could confirm, either way it would share a ground somewhere else in the system.
Yes I would still need a "tiny connector" on the BMS side, this looks like a standard PCB style molex socket.
Yes the USB dongle will accept the signal straight from the BMS (although untested yet) that is essentially what it's designed to do, and very likely the same as what's inside the JK converter..

The only difference I see with the JK converter is, it looks like it takes its power from the BMS rather than the output, I think this would mean full battery voltage so probably has some sort of step down converter inside.
OK, thanks for the explanation.

It seems mine has a slightly different connector on the BMS side and separate ones for RS485 and GPS.
 

Attachments

  • jkconnections.jpg
    jkconnections.jpg
    136.4 KB · Views: 6
Top