@transparent I am happy to pass the skillset(s) but assume it will be useful for others to see what it takes. I wish it was a trainset that just takes a bit of space, this will form part of the fabric of the house! 🤨  

Fogstar responds quickly, but it is a very long email thread.. The balancing was just one of the surprises that was not in the youtube video. 😉 

Just today Fogstar suggested me to upgrade the firmware of the Seplos BMS they shipped! And the Seplos apps require passwords that nobody seems to know, I already had to ask for that again..  

The power bench delivered 5A to start with and is the brand they recommended..  

I understand your questions about the BMS balancing capabilities, same occurred to me in the last couple of calls with them.. 

But Fogstar are not yet at optimisation stage supporting my adventure, it is more about getting the basics done.

When they recommended this BMS firmware upgrade, it was to solve an warning where the name of the battery is not recognised by the Solis, which would potentially also unlock some ability to set it to charge at the optimum voltage.. 

Ah... now I can see a photo,
and that changes the advice I've previously given here.

Firstly you've connected that Power Supply Unit at the near-end of the entire set of 16 cells.
In my earlier photo I had a 12A PSU connected in the centre of the row.

The cell at the far end of your set is receiving electricity which has been passed through 16 preceding connectors,each of which adds resistance.

Secondly, your PSU is connected using crocodile clips.
Those add a considerable resistance.

Fortuitously I've previously done that experiment, and took a photo as evidence:

My 12A supply is recording just 0.42A

This is the major reason why you'll be waiting until 2026 for your cells to charge up  😳

Thirdly, only now do know that you've bought a Seplos enclosure from Fogstar.
I had (incorrectly) assumed that you'd got one of Fogstar's own designs with the Pace BMS.

Posted by: @batpred

↑

When they recommended this BMS firmware upgrade, it was to solve an warning where the name of the battery is not recognised by the Solis, which would potentially also unlock some ability to set it to charge at the optimum voltage.. 

Ah... perhaps so.
But I have no hands-on experience of the Seplos BMS design.

Frankly it won't matter much whether the Solis inverter 'recognises' the BMS or not.
It's not going to act in any Smart manner by implementing that connection!

Chinese designers are very much 'into compatibility' as a sales feature.
But they make that claim when all that's happening is the Inverter App telling you the state of charge of the battery.

If the BMS attempts to report a fault-code, or anything that's "useful", there's no guarantee that the inverter will know what to do about it.
It may not even bother to tell you via a message on the App.

I've been running four batteries with three inverters for most of this year (2025).
At no time did any of the inverters change their operation as a result of faults/alerts!

@batpred Can we please have an update regarding your cell top-balancing operation?

Have you now got rid of those croc-clips?
With what effect?

Thanks

Posted by: @transparent

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@batpred Can we please have an update regarding your cell top-balancing operation?

Have you now got rid of those croc-clips?
With what effect?

Thanks

I had some very pleasant moments packing the cells into the box. They are apparently only 45% charged, and not their only job is to allow Solis to have a look at the inverter settings. When I get my UPS I will hardly remember how it started!     

Getting back to the BMS upgrade topic, the firmware update that is supposed to remove some potential wrinkles is in need of some guidance from Fogstar. I chased it but could only speak to the PACE specialist, the only one that knows enough about Seplos must be asleep at the moment!  

I think the pleasure of eventually getting it to work automatically will not be easily decoupled from all the weeks leading up to it. 

Still, I am not saying never again, as tempting to think I learnt enough and the next battery DIY assembly would be quick..😉

That's good news for the moment anyway.

Can we try to keep your Storage Battery saga all on one topic as things progress from here?

You mentioned putting cells into the box yesterday on the topic Battery Storage to run a Heat Pump where we were discussing battery chemistry
and the questions on wiring in your Solis inverter are on the topic Isolating the System for a Planned Power Cut.

Others will arrive here in months to come and not understand how they seem to missing bits of your story.

When I write a response to something, I tend to check my text against the Topic Title before pressing the Send button.

That gives me a moment to either add links to relevant discussions elsewhere,
... or to split what I've written across several Topics, according to the subject matter.

With hindsight we should probably have recommended a completely new topic for your installation...
into which I could then have added the cross-topic links for others to follow at a later date.

I now have multiple tabs open just to keep on track with what you and I have discussed!
aagh!

So following on the AC connections of the inverter ( on the topic Isolating the System for a Planned Power Cut.). Repeating my last post on it below. 

Posted by: @batpred

↑

@transparent 

Just wanted to share this link that Solis posted on the sensitivity of the RCDs. To be honest, I will not be looking into it in much detail as just focus on my specific case is hard enough! 

But you may have a lot more to say and perhaps influence the powers. A bit more focus from them to advise each market (or perhaps Europe as a whole) may help reduce safety issues.. Or even ideally they will defend the safer standards should be used everywhere..

When I spoke to a Solis engineer, I got the sense the reason for the RCD 100ma recommendation is, as we thought, unrelated to their inverters. Some experience of 30ma RCDs triggering easily when PV installed on metal sheeting roofs is supplying the inverter was hinted at. It seems working on industrial sites with PV on metal roofs needs extra care and electrical insulation.

But back to point, 30ma RCBO arrived and will have to be swapped at my "site" before the inverter can be commissioned.     

Oh, and still no answer on how to upgrade the SEPLOS BMS firmware...  

Have you tried going to Fogstar's website and looking for downloads?

It took me about 10secs to find the instructions there!  🤔 

Posted by: @transparent

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Have you tried going to Fogstar's website and looking for downloads?

It took me about 10secs to find the instructions there!  🤔 

I downloaded the firmware without a problem. The issue is the software does not upload it.  

I then quickly scanned the web for seplos apps to do it, but they need passwords etc - fair 3nough. Then Fogstar surprised me as they could not recognise them straight away... 😂

The seplos bms is not easily accessible from the outside so not a big issue that the passwords are posted everywhere.

What do you mean by "the software"?

Are you referring to a piece of code which runs on a PC and just does upgrades (via a serial port perhaps)?

Or is the upgrade system a feature of the Seplos mobile-phone App?

I would be surprised if the issue hasn't been covered by the Off-Grid Garage YouTube channel.
He's an Australian guy who isn't afraid to post passwords and 'inside knowledge'.

It could be an app working via Bluetooth or windows software connecting to the typical port for these devices, using serial protocol. 

As I hope this firmware update will not need to be done again, it is just something that Fogstar should advise on how to get through to the end. Hopefully after this update the inverter team will stop raising concerns about the battery not being supported! 

Some light at the end of the tunnel. Fogstar had some issue with their ticket management system, so it must have been quiet for the 3rd level engineering folks for a few days. 😊

The system now pushed the batched ticket updates.. 

And so happy to report the problem with the firmware update (windows software) is now accepted Seplos will get a call when they reopen! I do not have any illusion of a software development team behind it, a quick turnaround would be a welcome surprise. 

Solis is still bouncing tickets back unanswered quicker than they get them.