Solax sk-su3000e - Pylontech us2000c Battery BMS and CT Clamps - start again

[JC_UK]

Hi again,

I have gone back to the manual and checked the install through.....

I can monitor the inverter using the https://www.solax-portal.com/ portal and also the iphone app.

I have sorted out the CT clamp so now getting a reading from the daytime live meter tails, and this is now reflecting the power being generated/consumed in the property (additional FIT Inverter and Solar panels)

The inverter is still indicating a 'BMS disconnected', in Settings->Charger settings.
But the inverter and Solax-portal showing the battery details - voltage, capacity etc.

Does anyone have the uc2000c/us3000 batteries working with a Solax sk-su3000e inverter - old inverter - new battery......

Using the Self Use work Mode I can get the connected batteries to charge and discharge over the sunny day.

The problem I now have is when the batteries discharge they go lower than the 20% set in the Settings->Charger settings.....
At which I disconnect the batteries, to avoid other issues with the batteries.

Any ideas on how I can stop the batteries going below 20% capacity?

In my battery stack I have the following batteries all connected in parallel, and switch them off as required:
3x Pylontech us3000
3x Pylontech us2000c
4x Pylontech Extra2000

Is the 'BMS disconnected' the problem with charge/discharge issue?

Also tried to get the Force Charge working for overnight charging - but no joy with that yet.

Any ideas please?

Many thanks

JC

[Kommando]

Sounds like the Can link is not working and the inverter has defaulted to open loop and the voltage being reported is from the inverters own readings. The manual is silent on Can faults or the compatible battery list, suggest you contact Solax support or wait for someone with a similar working setup. One check is to compare the can-l and can-h pins on battery and inverter are the same as you may have to have a special cable if not.

[marshman]

As kommando says, seems like the BMS link is not working. Ideally this should use the CAN bus . Most common reason - assuming you have the correct battery selected on the inverter, is the cable is wrong. CAN bus only uses 2 wires - similar to RS485 - They need to be a "twisted pair".

As far as I can tell the pins used on the RJ45 are as follows:

On the Pylontech US2000C

pin 4 CAN-H
pin 5 CAN-L

On the Solax - if you have the manual then double check this is correct.

pin 4 CAN-H
pin 5 CAN-L

Check your BMS cable connects pin 4 to pin 4 and 5 to 5 - they are the centre two pins

Use as short a cable as possible.

[JC_UK]

Hi

I'm still struggling to the get the BMS connected.

Does anyone have one of these Solax inverters with Pylontech batteries connected?

If so can you help please?

Many thanks

JC

[marshman]

Think you are on a hiding to nothing trying to get the Solax inverter to communicate with the Pylontech batteries. There are numerous pleas for help on t'interweb on other forums and there is a long thread on this forum - none have a conclusion.

This is the thread on this forum: (worth a read as at least he (cojmh) got the batteries to charge and discharge "normally"

https://camelot-forum.co.uk/phpBB3/view ... a1a309b5f1

Also this thread on another forum which has a bit more information, but no conclusion !

https://powerforum.co.za/topic/10575-so ... 3000c-bms/

Sorry can't be of more help.

[JC_UK]

Hi all,

Thanks for the last post - I have already seen and read through both several times.

After a bit of head scratching and going back to my box of bits (cables, plugs, etc) I have at last made some progress.

I have also bought a made up cable RJ45-RJ45 to connect between the inverter and the newer UC2000C/UC3000 batteries
- no success - still getting the BMS Disconnected error message ......

So I tried an different tack.
The Extra2000 batteries I have - 2 of them came off a system running a Solax Inverter.
I added them to my battery stack along with brand new UC2000C batteries.
This battery stack was running pretty well for the past year and a bit, adding a couple more Extra2000's along the way and hanging off the SoFar ME3000SP charger.
On that stack I connected the Sofar charger to the UC2000C Can socket and the Sofar Charger ran without issue overnight charging as well as day time charging....

I now want to add more Solar Panel generation and I remembered the Solax X1 product and and a second hand came up for sale, so I thought that should work....... how hard can it be,,,,,,,,

So tonight after revisiting this again I thought I would try and connect the Extra2000 battery to the Solax inverter, with a BMS to RS232 made up and labelled cable - and success I now get the BMS Connected message and the batteries are no longer discharging past the limit set on the inverter.......
So as long as the battery charge and balance it should all work as was on the SoFar charger, but allow capacity for more solar generation.
And all agreed with the DNO......

I thought I had already tried (and failed) with the BMS to RS232 cable, but it works now!
As long as the lead battery is the Extra2000.

Now need to try some Forced Charging overnight to get some cheap(!) rate power into the batteries for the daytime.......

So I think I now have the working solution........

Big bonus is the great portal monitoring that Solax provide SolaX X-Monitoring and also the iphone app X SolarX Power - both far better than the latest version of the SoFar monitoring.

Next I'll try adding the UC3000's to the stack to provide more capacity, but some of the batteries (probably the UC3000's) will be relocating with the SoFar battery charger to another property crying out for battery storage.

No need to find some space outside to site the second hand solar panels I picked up on ebay....... :-)

Many thanks for all the patience and replies to this and my other threads......

JC

[Kommando]

I have dropped the Solax monitoring and get the info realtime on a webpage locally running on an ESP32, turned off the data link to China and process all the data in a Solar-log data logger also on the local network.

https://freepocket.chrisoft.io/

https://blog.chrisoft.io/blog/2023/10/0 ... res-solax/

That OEM Solax wifi module links into China and can be used for remote access, too much of a security risk for me.

[JC_UK]

Hi all,

All working now.

See:
https://camelot-forum.co.uk/phpBB3/view ... =14&t=2893

Many thanks

[Fintray]

Hi all,

All working now.

See:
https://camelot-forum.co.uk/phpBB3/view ... =14&t=2893

Many thanks

Glad to hear that you got it all sorted .