Pretty sure my batteries are balanced enough. Each is 3.663V so I think it's time to put everything together!

Little update. I've got the batteries in and compressed. I added the bus bars and the BMS leads. However my torque wrench needs an adaptor to take the 10mm socket... Very annoying. I'll grab one tomorrow and finish torquing and then close up. Honestly I think I've spent maybe 2 or 3 hours max putting this together. Most of that was the front panel Jenga with bolts. 

As I said before, this thing is a tank. Once it's in place it's probably never moving. Or if it does, someone else can have that job.

Battery is finished. I've not installed it yet as I need to swap it out with the Pylontechs. But its ready, and tested.

@batalto - Your experience in assembling this Mason box matches what Off-Grid Garage was saying on this YT videos. You even both had bags of loose components which split in transit!

Note that he uploaded an entire episode when he discovered that the Seplos BMS unit did not provide balancing in the way he expected.

As he charges his collection of batteries only from solar, they rarely attain 100% capacity. Operating between 20-80% is the usual pattern. But he discovered that the BMS only engages the balancing algorithm in the very late stages of charging... at a cell voltage which he was unlikely to attain.

We will be interested to learn if you also experience this behaviour... although it will take several days of usage in sunshine for you to analyse whether you agree with his observations.

He uploaded a final overview of the Seplos boxes, of which he built and tested two variants. His style is to intermix facts and personal opinions, so you'll need to separate these to appreciate what he's actually reporting.

@transparent I dont really have any issues with the kit. Yes one of the bags was split, but it was a small thing. I also found the missing bolts, they were in the front plate. The only thing I didnt have all of were the little copper washers (I was 3 short). It was very easy to put together and follow along.

I now need to connect to the BMS and this is giving me issue. The adaptor I ordered wasnt in the box (they forgot it) so I cant seem to connect to the CAN. I don't actually know if its an issue - but I would like to connect to see whats happening. I've only ever connected to my Pylons once (to do a firmware upgrade). So I don't really see it being an issue TBH.

@transparent looks like seplos have been listening

Posted by: @batalto

The only thing I didnt have all of were the little copper washers (I was 3 short)

That's a bit worrying. If you had no copper washers then it would indicate that someone forgot to pack them. But to have three missing is more worrying. There remains a risk that they've fallen out of the bag and become lodged within the hardware. Let's hope they're not creating a short-circuit somewhere important.

I'm really glad Seplos have listened to customer feedback on their packaging.

I'll be even more impressed if they re-work the algorithm to handle balancing. Ideally, make it definable via a Modbus command.

There will be some users who regularly charge their cells above 95%, for whom the existing regime works fine and with minimal 'losses'. Others, however, will use such a large battery with sporadic/indeterminate charging levels. There needs to be some way to invoke a balancing schedule when required at lower SoC.

Have you considered sending them an email with the URL for this discussion?

@transparent the bag for the little copper washers was still sealed. I think when they put them in, they were just 3 short. I just made sure that everything was balanced e.g. both sides touching the same material. I noticed Andy in his build didn't even bother with them!

I'm just working with Seplos as I cant connect to the BMS. Might be a cable issue on my side, so I might need to get a new one as at the moment I cant seem to connect? However I can use the battery as is. The BMS connection is just to tweak settings. I have a cable for Pylontechs, but I've only ever connected to it once to update the firmware. For me, I just want to connect and forget.

I was going to swap batteries this morning, but the Pylontechs were empty. Just letting them refill and hopefully i'll be able to swap them this afternoon. Now if I could ever get the installer to come and install the ME3000SP I could have 30kwh of batteries running. I'm tempted to just install myself to get on with my life.

Is it the fact that your storage batteries are grid-tied which means you need an MCS-approved installer to connect the Sofar inverter?

Have you already got approval from your DNO for the installation?

@transparent I am aware. The issue is that the installers have kept me waiting 2 months now, my patience is wearing thin. As the installer said to me "No one is going to come and check to see who installed your kit" - My 1 day job isn't interesting enough for anyone at the moment. He told me he has had 160 solar enquires for install he is working through.

Clarification of my multi-faceted question (for the benefit of others who will read this dialogue in future):

A: If you have applied for and obtained Grid-tied approval from your DNO, then you own it. That permission doesn't oblige you to wait for a specific installer.

B: If you already have an existing grid-tied inverter, and are replacing it with another that exports no more than the first one, then you do not need to re-apply to the DNO. You may, however, fall foul of the MCS rules. The replacement inverter may not be an 'approved product' on their database. Nevertheless there is currently no method of this being identified nor anyone held responsible unless/until your replacement inverter goes Pooph! At that point your DNO, house-insurer and MCS might become involved.

The MCS approved contractor is the mechanism by which the home-owner can claim Smart Export Guarantee payments from their energy supplier. Without the MCS certificate number, the payments to you cannot be processed. But if the home-owner doesn't wish to claim trivial SEG payments, or the revised installation is now to be operated off-grid, then there's another grey area.

Installations that are off-grid from the outset fall outside both sets of rules:

• the DNO doesn't need to give its consent because no grid-export is to be made
• the MCS isn't involved because you don't require a certificate from an approved installer. No SEG credits will be sought from your energy supplier

That means there is no safety checking of DIY electricity-storage installations.

All of the devices and wiring operating at ELV levels (nominally 48v) do not require a qualified electrician to install, test and provide a Part-P certificate.