Idiot's guide to a self build battery

[Joeboy]

Put together a homemade busbar mount/separator with a flashcard. Total cost, zero. Will add a clear plastic cover once I have finished the DC cables. On standby for more 8mm cable crimps and the 2nd busbar. Might look at making up a mount for the balancer and then it's clamping endplate time x 6. This is a very satisfying job.







Assuming DC cables for both sides should be kept as close as possible to total equal lengths?

[Stinsy]

Busbar mount looks really good! You’d have to be trying exceptionally hard to inadvertently cause a short with a spanner or whatever!

A piece of clear plastic on top would really finish it off…

[Joeboy]

Busbar mount looks really good! You’d have to be trying exceptionally hard to inadvertently cause a short with a spanner or whatever!

A piece of clear plastic on top would really finish it off…

It's in the mix, Chinese carryout lid.

[Joeboy]

Made up a cardboard simubatt as the real ones are still in the Zouhai factory. Can begin making up the endcaps. The finished units will not sit that far forward.

[Joeboy]

That's the power off the Frankenstein breaker and onto the first busbar. Also T'd in the standby 2kW 240V inverter. Means If a fault develops on the new LF280K side I can pull Frankenstein to isolate the LF's and the s/by 2kW in one go. The main system can continue as is.

I now have 6 polyurethane coated endcaps just about ready to fit. They will be clamped with M4 nuts & washers. Same as the right angle roofhanging bracketry. One size fits all rather than buying twice.

A few bits n bobs to tidy and then I'm on s/by myself for the batteries (drums fingers).... might have time to tidy the workshop.

[Joeboy]

As I had tidied up for the day I thought I'd map out the battery build so I can work out the large DC cable req's (1 mtr of each). This is the first time I've actually done that.

For anyone not knowing, it's a 15 battery stack being added and it is in series (+ to -) connections. This increases the voltage of the battery stack. In my case each battery is named as a nominal 3.2V.

15x3.2= 48V which is also the voltage that our existing Pylonecth stack operates at.



I am now going to check the cell balancer wiring and add a legend to the battery stack drawing. I like to do it this way so I'm not frantically scrabbling about trying to work it out on the day.
I do the same with my PV, really simplifies it by spreading the brain strain.
£1,687- 15 of LF280K (A) batteries incl del, bus bars n bolts
£60.72 - 1 of 15s 5A balance board.
£60 framework and bolts
£20 DC-DC variable 20A buckboard (battery charger)
£38 Amp clamp (AC AND DC capable)
£60 Frankenstein breaker & 2 125A fuses
£26 2 of 2mtr lengths 25mm2 cable
£12 Hammer crimper
£36 Solder kit gear, 18awg cable & heatshrink kit
£24 lugs for AWG2 & AWG18 wire, reel of solder.
£13 100A busbar to match spare.
£14 1mtr each of red & black 25mm2 cable
£2,063 total

[Oldgreybeard]

Great idea to draw up a schematic, IMHO. I've spent a few hours retrospectively drawing up stuff and laminating the bits of paper. I bought some wall mount document holders from ebay, and have fixed them to the wall by stuff, to hold the manuals, schematics and any notes I've made about settings etc. Hopefully that may make life easier if anyone else needs to work on anything.

[Joeboy]

DPD tracking No just in, woohoo!

45 to 60 days is the estimate so I may be a little ahead of myself.

In saying that, I'd guess i'm up at about 30 hours into this so far. I would not want to be doing all of this while the batteries were sitting there looking at me (they do that you know).

A quick work out puts the stack LF280k's at 13.44kWh storage capacity. Pylontechs come in at anything from £950 to £1,500 each for a US2000C. That's a range of £5,319 to £8,400 excl delivery or any govt percentage (0% at the moment) plus fitting to match the stack size.

We'll see how much govt levy I get hit by, so far though we are on course for these LF280k's to come in well under the current price mark. Its a lot of work and great fun but my kids are up and away, I am retired and like this stuff. Might not be for everyone. In saying THAT, its hard to resist when you look at the price point and realise that its another hidden bonus of owning a battery stack with its own BMS. Just thoughts to ponder if you are thinking of going this way.

[Stinsy]

I too benefit from stretching the “thinking” over a period of time. There can be a number of iterations in the design, and problems overcome before the materials are in front of you.

[Joeboy]

Timber work continues, a trial build and measurement of No1 clamp. All good, will trim rods once assembled on batteries and it will slide in.
I'd be a liar if I didn't say I was bricking it a little. Glad it fits!