@transparent I've ordered a 1S LFP charger from ali, 25a, so that gives me a bit more power compared to my bench PSUs at work. I need to get my Eltek Flatpack setup to output 3.65x16... not too difficult to do.

Ah... OK.

I'd misunderstood.
I thought you were looking for a solution which would arrive before Christmas.

Is a dedicated 25A 1S charger from AliExpress any cheaper than buying a generic power supply with 25A output (also from AliExpress)?

It did appear to be cheaper, yes. Ideally I'll have something up and running before xmas, but it's not the end of the world if I don't. I've got until March/April time to get this pack all installed in it's new location, along with a domestic rewire and consumer unit change.

Text disappeared but I've made a start on mounting hardware and making up matched length cables. Here we are on 35mm welding cable. Rest will be in 25mm. Rather than run in conduit I will be making up a locked Perspex cover for the cabling/battery section. May have to remount everything about a foot higher, but will see if I can fit the rest in with room for batteries below tomorrow.

Can you explain the need for a locked perspex cover please?

I only cover bare battery terminals/connectors when there is a risk that I might cause a short-circuit by something metallic falling against them.
Otherwise I leave copper busbars etc open to the air.

You seem to be heading in the opposite direction...
... putting a perspex sheet between yourself and the high-current cables, which are insulated anyway

... and then fitting a lock too 😲 

@transparent I keep my children in there at night. Little fingers. Like 45 of them in total (fingers that is).

Previous suggestion was conduit for the single insulated cables but if it's overkill I won't bother.

I think you're being over-anxious on the possible risks.

The reason that we can work on these batteries without being a qualified electrician is that they're below 75v and hence classed as Extra-Low Voltage (ELV). You won't feel anything at all if you place a finger across a +ve and -ve terminal.

I can quite see that you'll want to avoid your 4½ children short-circuiting the connections with a steel ruler to "see what happens".
So you need some barrier to keep them away.

But they're not going to be hurt by 52v DC.

Just an FYI, yes you can easily assemble the 280L when in vertical mode.

Blown up the BMS so I’ll need to sort another one, but I’ve got this far. Wouldn’t be more than half an hour away from buttoning it up if I hadn’t fried the BMS 🤦‍♂️

How???????

@makia2023 

are you putting a heating element in the case? i was an 'early adopter' of the 280L some months back and suggested some changes to Seplos, a couple of which they added. The one thing mine is lacking was a heating pad, so ive added an external one (reptile tank) via a 240v temp controlled device. At the moment i also added an insulated plywood casing around the 280L but it now looks ugly and having thought it through further, i dont think its actually necessary on the basis that the Seplos heater doesnt come with a recommendation to add insulation! 

My thoughts were that if the Seplos heating element is internal then adding an external one would achieve the same effect ...??? Happy to hear of anyone else's thoughts? i could then also add just one piece of rigid insulation on the rear to 'direct heat in one direction' and cut heat losses. 

My battery is in an external unheated utility room, hence the desire to add some form of case heating. 

Here's the relevant section of the EVE 280k LiFePO4 specification for cell temperature:

Even in an unheated utility room, it's unlikely that your cells' temperature will fall below 0°C in the UK.

A mains-fed reptile heat mat also seems wasteful of precious energy.
Haven't you got another readily available source of low-level heat nearby?
The fan outlet from your inverter(s) can't be that far away!

@makia2023 - I too await hearing @hughf's epic tale of how his new Seplos BMS has departed this life...
... and whether he intends replacing it with another of the same model.

Given a free choice, I'd probably be opting for one by JK with inbuilt 2A active balancing.

Batrium and Victron would offer even better balancing and SoC monitoring, but at higher price.

PS. I've just noticed that Fogstar have stocks of the JK PD2A16S-20P, which has similar size profile to the deceased Seplos BMS in Hugh's Mason box.

That model offers 200A charge/discharge capability and 2A integral active balancing.

The long rectangular format would make it simpler to fit in place of the existing unit.

The £190 price tag includes, fixing bolts, cables, JK's 110mm external touch screen...
... and unlimited support from this enthusiastic forum over the Christmas break. 😋