New Fogstar 15.5kWh upright solution

vaugi · 2023-11-19T11:17:06Z

Just noticed Fogstar have a new upright solution (coming soon). Given that it's Grade A cells, battery heater, cell balancer and 8yr warranty at £2500 incl VAT, is there much point DIYing with a Seplos anymore (at least for single bank solutions)?

Page 11 / 11 Prev

Energy Storage

Last Post by Transparent 2 hours ago

122 Posts

14 Users

34 Reactions

20.7 K Views

RSS

Batpred

(@batpred)

Trusted Member Member

Joined: 9 months ago

Posts: 42

13/10/2025 12:46 pm

@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..

ReplyQuote

Transparent

(@transparent)

Illustrious Member Moderator

Joined: 4 years ago

Posts: 2572

13/10/2025 1:58 pm

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!

This post was modified 2 hours ago by Transparent

Save energy... recycle electrons!

ReplyQuote

Page 11 / 11 Prev