BMS communication issues

[Swwils]

If it helps I can dig out the part number for the required cable if you like.

[Tinbum]

I would think solax cable should work if working on CAN, but not if RS485.

[cojmh]

Thanks for the continuing messages

I have looked at the US2000 pins on the RJ45 and they come up as the following for CAN:

1 -> Nothing
2 -> GND
3 -> Nothing
4 -> CANH
5 -> CANL
6 -> Nothing
7 -> Nothing
8 -> Nothing


I have gone with CAN as this is what the original SOLAX cable indicated (by being connected to pins 4 and 5 on the battery end.

I have checked the US3000C pins on the RJ45 and they come up as the following for CAN:

1 -> NULL
2 -> NULL
3 -> NULL
4 -> CAN-H
5 -> CAN-L
6 -> CAN-GND
7 -> 485A
8 -> 485B

So it would seem that the CAN connections (H and L) are the same but the GND is different and I believe that someone has already posted that quite early on in the thread .... so apologies ... just catching up it would seem.

So my question is the GND (Ground) as I could not find this connection on RJ45 end that goes into the inverter as I said in a previous post there are only 2 wires that are connected at that end.

So would I be right in connecting pin 6 of the battery end of the cable to the metallic sheathing in the RJ45 cable itself?

That is the only thing I can think of that is incorrect and that I can do. After that I am worried it is something physically wrong with either the inverter or the batteries.

Thoughts welcome?

Thanks,

Jon

[Tinbum]

It should work without the ground being connected.

[cojmh]

I have tried everything from the various manuals and I am sure that one of the cable combinations I have tried should have worked if the systems were compatible.

I am now beginning to think that I should be looking at connecting the BMS via the RS232 interface (i.e. the BMS port on the Solax unit which supports RS232 and the Console port on the Pylontech batteries).

Something else I don't have is the temperature sensor for the Solax unit (I guess the installed never left it with the unit) .... could this be preventing the unit from working do you think?

[Tinbum]

Rs232 won't work as that's for consol not bms. The temp probe is just for lead acid so won't be needed. It sounds like a settings issue.

[cojmh]

Hi,

I tried the RS232 communication and the batteries did seem to do something different - but as you say it is not going to work for a BMS connection (although interestingly enough the Solax documentation has a diagram that shows the BMS port on the inverter connected to the console port on the battery unit - although it is a generic drawing as opposed to pylontech specific).

So I have gone back to the CAN cable I made up which follows the connections that are specific to each unit as per the respective installation manuals

Solax -> Pylontech

(CANH) 1 -> 4 (CANH)
(CANL) 2 -> 5 (CANL)
(GND) 3 -> 6 (GND)

I have gone through all of the settings on the inverter including the password protected area (The password for reference is 2014)

The only settings I can find are:

Battery Type -> Set to "Lithium"
Minimum Capacity -> Originally set to 20%, I changed it to 10%
Charge Cut Voltage -> 53.5V - I have left this alone as it seems to be within the Pylontech documented range
Discharge Cut Voltage -> 47V - I have left this alone as it seems to be within the Pylontech documented range
Battery Awaken -> No, I have tested this as apparently it will get the batteries to force charge but as my batteries are full, it make no real difference whether I leave it alone or trigger it (it then reverts back to no)

Apparently there is another setting for EPS discharge voltage, but as I have nothing connected on the EPS I have ignored this.

That is literally everything I can find settings wise on the unit and in the documentation.

From everything I have read from the documentation the communication is CAN (and can also do RS232 - but not for BMS). I am pretty confident the cable is correct according to the documentation and the settings (above) are correct as far as I can tell and there is nothing else that I can change apart from one DIP switch (dip switch 2) on the Pylontech unit which is for CAN terminal resistance.

Everything I have tried has not changed the status on the Solax inverter away from "BMS Disconnected"

So the only conclusions I can draw are either:

1. The "BMS Disconnected" message on the solax is misleading me (although I have only witness the batteries charging and not discharging)
2. There is a communication incompatability between the inverter and batteries - so they will not work together.

I really don't know where to go next apart from trying to contact Pylontech in China to see if there are any BMS changes between the US2000 and the US3000B

thoughts are welcome (as always) and thank you for all the responses so far

[Joeboy]

Hi,

I tried the RS232 communication and the batteries did seem to do something different - but as you say it is not going to work for a BMS connection (although interestingly enough the Solax documentation has a diagram that shows the BMS port on the inverter connected to the console port on the battery unit - although it is a generic drawing as opposed to pylontech specific).

So I have gone back to the CAN cable I made up which follows the connections that are specific to each unit as per the respective installation manuals

Solax -> Pylontech

(CANH) 1 -> 4 (CANH)
(CANL) 2 -> 5 (CANL)
(GND) 3 -> 6 (GND)

I have gone through all of the settings on the inverter including the password protected area (The password for reference is 2014)

The only settings I can find are:

Battery Type -> Set to "Lithium"
Minimum Capacity -> Originally set to 20%, I changed it to 10%
Charge Cut Voltage -> 53.5V - I have left this alone as it seems to be within the Pylontech documented range
Discharge Cut Voltage -> 47V - I have left this alone as it seems to be within the Pylontech documented range
Battery Awaken -> No, I have tested this as apparently it will get the batteries to force charge but as my batteries are full, it make no real difference whether I leave it alone or trigger it (it then reverts back to no)

Apparently there is another setting for EPS discharge voltage, but as I have nothing connected on the EPS I have ignored this.

That is literally everything I can find settings wise on the unit and in the documentation.

From everything I have read from the documentation the communication is CAN (and can also do RS232 - but not for BMS). I am pretty confident the cable is correct according to the documentation and the settings (above) are correct as far as I can tell and there is nothing else that I can change apart from one DIP switch (dip switch 2) on the Pylontech unit which is for CAN terminal resistance.

Everything I have tried has not changed the status on the Solax inverter away from "BMS Disconnected"

So the only conclusions I can draw are either:

1. The "BMS Disconnected" message on the solax is misleading me (although I have only witness the batteries charging and not discharging)
2. There is a communication incompatability between the inverter and batteries - so they will not work together.

I really don't know where to go next apart from trying to contact Pylontech in China to see if there are any BMS changes between the US2000 and the US3000B

thoughts are welcome (as always) and thank you for all the responses so far

You've belled the cable end to end not just went on colours?
Nothing wrong with a mail to pylontech to seek clarification.

[cojmh]

Yes,

Every time I have made up the cable I have tested with a multi-meter from RJ45 connector to RJ45 connector. So I know that the PINs are exactly the as I have drawn them.

thanks,

[Joeboy]

Yes,

Every time I have made up the cable I have tested with a multi-meter from RJ45 connector to RJ45 connector. So I know that the PINs are exactly the as I have drawn them.

thanks,

Sometimes it's the simplest things. Ah well, pylontech it is then. I wish I knew enough about your system to see if a data runaround can be performed to test the solax on its own.