@batpred 

That's right the Seplos BMS manages the pack and communicates with the Inverter.

The JK active balancer I think you are referring to is completely independent and only balances the individual cells, nothing more, so that is very unlikely to be your issue.

I have 3 of these upright Seplos packs from Fogstar, which I've upgraded the firmware (and downgraded) from 1.2-1.3-1.4 and have had no issues at all, also running on a Solis S6 inverter (AC Coupled).

The JK active balancer works very well to keep the cells all aligned.

I haven't upgraded to the 1.5 firmware yet as I'm happy with where all my 3 packs are.

@batpred 

Did you build your pack, or buy it pre built?

It is a matter of luck. 2ith Fogstar "instructions", too much variation can be expected... 

But let's see what fogstar say. It may be a while... 

Issues still under investigation by Solis...

Fogstar do not market their batteries as precision kit. And they may have a point when they say "it was just a blip in comms". 

SITREP #5 (I think)

Milestone completed today, got my solar array working and attached to my Sunsynk Inverter. 

6.4kW - running on X2 MPPT strings.

Question - is there any setting on the sunsynk that I need to consider? no export required (yet) but how does it decide to charge the fogstar battery, prioritise Load and/or charge from grid overnight?

Posted by: @batpred

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They shared the graph below. It shows that the battery is momentarily reporting a soc, voltage, etc of 0 and then it all changes back to normal. This is not normal behaviour...

May I pick up this comment from last week?

As I understand it, you have a Jikong Active Balancer and a Seplos BMS connected to the same set of 16 LiFePO₄ cells.

There's nothing wrong with that strategy...
... provided both units have the connections they require.

For the benefit of others, this is what a JK Active Balancer looks like:

It has only low-current balancing wires connected to each of the battery terminals.
That's 17 connections for a 16-cell (16S) battery.

The Active Balancer can handle up to 22 or 24 cells, depending on the model.
I've cut short the extra unused wires in the photo above.

A JK BMS is similar, but would also have the (large) wires which connect to the battery negative terminal.
JK use two blue wires in parallel to make that 0v connection.

The +ve connection to the battery doesn't go to the BMS unit, but straight to the inverter(s), via whatever protection devices you've decided to have.

Since @batpred has a Seplos BMS unit, I would expect it to be positioned on this 0v connection route to the battery negative terminal.
A photo would be useful to clarify that.

So how does that Seplos BMS 'know' the overall battery voltage?
It should have one thin (red) wire connected to the +ve battery terminal.

Ie it's not going to do any balancing between cells, but still needs a voltage to power itself!

That is also the wire which tells the BMS what voltage the battery is currently at,
which it passes on to the (Solis) inverter using the CANbus or RS485 data connection.

Do you have that one red wire present @batpred ?

And where is it connected to on the Seplos BMS?

@transparent 

The wires are all as per Fogstar "instructions" with some common sense where the instructions skip some steps.

All the boards including the seplos bms, came with the kit order. Fogstar never provided me with anything beyond it. I upgraded the seplos bms firmware to the latest, so the inverter could use the pylontech protocol for bms communication.

Regarding this problem Solis identified, I downloaded the BMS logs. But unfortunately this snapshot info is hourly, so it does not help pinpoint the issue. I would not be surprised if Fogstar emphasises the lack of 0 reads on the BMS logs .. 😌

Solis s6 lists 20 or 30 battery brands in their menu but Fogstar does not figure. They are also not liaising with Solis regarding this, so I am doing my best to keep the diagnosis effort going. And avoid any claims that it is not a supported battery.. 

As for the jk board, it is accessible via Bluetooth. Do you know if firmware upgrades are available for it? I could open the battery pack but I was so happy when I could close it, so I am trying to hold onto those happy moments. 🙂

We're at cross purposes.

You're telling us about Instructions and firmware upgrades...
... whilst I'm writing about little red wires 🤨 

Without knowing what you've connected where, I don't think anyone here will be able to say why the inverter is reporting 0v on the battery.

@transparent 

I have 3 of these units and extensive knowledge of building them (and liaising with Fogstar), particularly around the JK Active balancer.

I wouldn't waste your time trying to help Batpred (I have tried).

Batpred seems to be more interested in how badly Fogstar have treated them.

I don't get it because JK to solis is one of the most common configs for these.

Fogstar are great.

Posted by: @ggw

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SITREP #5 (I think)

 

Milestone completed today, got my solar array working and attached to my Sunsynk Inverter. 

6.4kW - running on X2 MPPT strings.

Question - is there any setting on the sunsynk that I need to consider? no export required (yet) but how does it decide to charge the fogstar battery, prioritise Load and/or charge from grid overnight?

The settings for this are accessible via either the app or the website, and are found the Equipment tab, then the 3 dots and 'Settings', which will show up the System Mode option.  On there you can switch export on and off, prioritise the load and set timers (screenshots show how mine are set).  There are 6 slots available, that have to start and end at midnight, but it's only the ones that are ticked in the boxes near the top that trigger grid charging to whatever % level you set.

The minimum level you set is also relevant as the system will revert to grid operation if you hit one of these numbers, which is mine are set to 15 when I don't want it to be grid charging.  If this was set to 50 in any period, the batteries would only discharge to that level before switching to grid power.

Hope this helps with your configuration.

@sheriff-fatman 

Thank you, seems to have gotten it running.

Question - what generation did anyone get today in the UK?

I got 0.5Kwh on a 6.38kw South facing ground mount. Seems so bad it's faulty 🤣 - but it was a very overcast day.