Posted by: @swwils

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

Fogstar are great.

I am not surprised you don't get it!!! 🤣 

Fogstar fan club members are not always obvious to spot, but you give it away! 

Just read the posts and learn about JK. 

Posted by: @bash

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

Easy to spot the second collaborator. 🤣 

So what is your interest in HA and Solis? 

Posted by: @transparent

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

Without knowing what you've connected where ...

@transparent

The readings are 0 for amps, 0 for volts, etc (for the complete battery pack). The inverter does not read voltages for specific cells. We know that the JK balancer is the one reading voltages for each cell level. 

I assembled the battery kit following Fogstar's video instructions (and reached out to them multiple times, since the video did not match what they shipped). People that do this for a living would be aware of the differences between the video and the latest kit.   

At 14min:11sec, you can see the final connection to the JK. 

In summary, Fogstar designed the wiring from the JK to the cells including two boards. I can't remember if there are any active components in these boards. But anyway, each of these is connected to the JK via a busbar. So the wiring to the cells is from these boards. 

Coming back to the issue I am experiencing, it smells of comms. 

One challenge is that, unsurprisingly, Fogstar/Seplos are not a battery that Solis supports. Hopefully these issues will be solved soon.  

The reason I posted this here is so readers can make their own mind as to whether this battery assembling process is anything they would want to get involved in. 

One consequence of a DIY process is that, whenever there are problems, it is not possible to get Fogstar as the retailer to solve them with the engineers of the inverter of your choice.

The fact is that, if I bought a ready made battery, I would also have the advantage that solving issues with integration of the product with the inverter would be much simpler. And it would have cost less.  

Posted by: @batpred

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The readings are 0 for amps, 0 for volts, etc (for the complete battery pack). The inverter does not read voltages for specific cells. We know that the JK balancer is the one reading voltages for each cell level.

Inverters can pick up cell voltages and the overall battery voltage using the data-link to the BMS.

You've stated that your battery has both a JK Balancer and a Seplos BMS.
The video clip only shows one such unit...
... and then you've also stated that the video doesn't match what you received from Fogstar.

I could equally well point to 15m20s on the video where it shows a requirement for the battery +ve terminal to be connected to the BMS alongside the large current-carrying wire.

Leaving that wire disconnected would result in the BMS reporting 0v to the inverter.

But that wouldn't necessarily reflect what you've assembled.
I'd be indicating the assembly process in the video rather than commenting on what you'd actually done.

We would need to see photos of your particular battery, showing the Jikong Balancer and the Seplos BMS, together with their wires to the
PCBs which connect to the cells within that assembly.

Posted by: @batpred

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Fogstar/Seplos are not a battery that Solis supports.

Solis might already 'support' another named battery which also uses JK BMS or Balancer units.

Nor is it essential to have any data connection between a BMS and an inverter.
Many of us operate multiple batteries and inverters with no such data connections.

@transparent 

My conclusion is as you have noted, that the connection(s) to the cells need checking.

There are a few, so one may not be seated correctly and would be the first thing I'd check.

Solis would use the Pylontech protocol, and should be no problem as noted in my Fogstar/Seplos units connected to a very similar Solis inverter with no communication issues.

Posted by: @transparent

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Solis might already 'support' another named battery which also uses JK BMS or Balancer units.

Nor is it essential to have any data connection between a BMS and an inverter.

When raising queries with an inverter manufacturer, one´s effort can be worthless if related to a battery brand that is not supported. In that case, the individual is of course able to resort to other means (like this forum) to try to resolve it. But many of us want to keep it simple and have a first option that only involves the inverter and battery supplier. 🙂 

Seplos and Fogstar are not listed as supported by Solis. 

I think I managed to get to a partial resolution of the issues I reported about BMS info from my Fogstar kit not being processed by Solis. But I made sure to not mention the battery brand, etc. 

If I find any photos of the JK wiring on my kit, I will post them here. 

They all use a standard or derivative communication and you can convert between without much issue, I have an esp doing that on my setup because I also take the data into HA. It's a super simple protocol.

In any case as already mentioned most inverters can do it just from the battery voltage alone with no BMS comms.

Posted by: @swwils

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In any case as already mentioned most inverters can do it just from the battery voltage alone with no BMS comms.

Sure, that makes sense, it is what happens when it is out of warranty, etc. Anyone buying a battery that´s not a supported combination, needs to be ready to, not only roll up their sleeves during installation but also keep them up for the duration. 

And this begs the question: is there much difference if it is just bought off ebay or aliexpress (provided also backed by a UK payment method)? 

I am considering buying another and add it to the pack, assuming it is just a matter of daisy chaining the CAN cable and the power leads..

Posted by: @transparent

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Posted by: @batpred

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The readings are 0 for amps, 0 for volts, etc (for the complete battery pack). The inverter does not read voltages for specific cells. We know that the JK balancer is the one reading voltages for each cell level.

Inverters can pick up cell voltages and the overall battery voltage using the data-link to the BMS.

You've stated that your battery has both a JK Balancer and a Seplos BMS.
The video clip only shows one such unit...
... and then you've also stated that the video doesn't match what you received from Fogstar.

The video shows the JK balancer, but the connection of the SEPLOS BMS board is also shown at another point. But there are some differences between the video they shared to me and the actual kit I received. I remember that the fuse assembly components would not fit as snuggly as in the video, etc.

I can reassure you that when I connect to JK using bluetooth and their app, there are sensible voltage readings for all cells. This and the fact that amp and other readings were occasionally 0 indicates a comms issue and nothing wrong with the wiring assembly. 

So in essence, anyone buying these Fogstar kits is expected to use "common sense" when the video does not match what they are sent. Since "common sense" is not an exact discipline, there will be variance and in the worst case, mistakes will be made. 

Posted by: @batpred

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I am considering buying another and add it to the pack, assuming it is just a matter of daisy chaining the CAN cable and the power leads..

Running the power-leads in parallel is OK,
but not so for the data cables, whether they be CANbus or RS485.

Before needlessly diving into the technicalities of battery data wiring, could you first state why you want any data communications between the batteries and the inverter?

Returning briefly to the point of putting power cables in parallel, bear in mind that the resistance of those power cables is hugely significant.

If the connections to one battery use wires which are of different length, or cross-sectional area of copper,  then the batteries won't be used equally.

I also prefer having safety devices on the power wires for each battery.
That allows them to be isolated in the event of a fault, or for maintenance.

I have fuses, over-current trips which can be manually switched, and high-current solenoids for connection to a microcontroller if required.

@batpred 

Maybe you should buy your additional battery pre-built this time?

If you do get another it is pretty simple to daisy chain them. It is described on Fogstars website, you just need another data cable and connect the master in port 2 and the slave in port 1. You'd obviously need the extra power cables, and as Transparent mentioned, make sure you size them correctly. 

I originally daisy chained the power cable on my 3 units, but decided to add a busbar so I could isolate them individually if required for maintenance. Just make sure you size the power cables correctly and ideally don't have too much excess on the cable.

I'm glad I have 3, which is about the limit I can sustain in the off peak charging window as it is surprising how much they get used, especially in the winter and my HP isn't even installed yet (3 weeks to go).

The Fogstar batteries are an absolute bargain. I can't see them getting much cheaper, other than an offer code, which they do a few times a year.

My 45kwh setup self installed was under £5000 for everything, so the ROI especially with the HP coming at the end of the month is fantastic.

In terms of options for ready to use batteries, I saw the following on ebay:  

- one going for £1000: Solar Energy 15kWh Home Storage Battery for Solar & Backup 51.2V 300Ah LiFePo4

- for £1100: 48V 300Ah Lithium Battery 15KWh Solar Energy For Home Storage PV BMS

- similar for ~1050: LUX-X-48100LG01 low voltage stackable LFP solar battery storage

When I order one of these, I think I will go with a radial setup from the Solis inverter (obvs for the DC cables). This will add to robustness and simplify maintenance. 

The comms cables, I will daisy chain like @bash suggested. 

And as @transparent indicated, aliexpress may be advantageous vs ebay to source lifepo4 batteries.