Idiot's guide to a self build battery

[Joeboy]

Swedish style modular newspaper rack?

[Joeboy]

Cell balance board resting on small liquid metal fixed machine screws. Hopefully I've been as neat as I think or the board is welded at the corners! Will remove tomorrow (hopefully), isolate the posts from the board and install the whole unit in final position. Board is airgapped at the back. A great day!

[Joeboy]

https://www.linkedin.com/in/colin-deng-2b4277238
This is the guy I've been dealing with, absolutely top notch.
https://m.alibaba.com/products/shenzhen ... nergy.html
This is the company.

[spread-tee]

Apologies for the daft question, but why do these batteries need clamping like that? is it functional or just to keep it all safe and tidy?

Desp

[Joeboy]

Apologies for the daft question, but why do these batteries need clamping like that? is it functional or just to keep it all safe and tidy?

Desp

The cases can expand when charging, clamping speads the load evenly through the pack and minimises risk of deformation/damage. Each pack can expand 0.5mm.
The threaded rods will be nipped up left to settle for an hour and rechecked before loading in for hook up.
No daft questions pal, that's the unasked one's!

[Moxi]

Hi Desp,

More learned explanations will follow I am sure but AFAIK the batteries have a tendency to swell and distort when charged and discharged unless they are positively restrained. The material surrounding the cell is therefore a barrier layer rather than a "case" - I have seen these cells in steel cases, wooden cases, plastic etc etc, on occasion i have seen examples of batteries wrapped in heat shrink and examples in this instance where some swelling has occurred.

Not sure what causes the swelling but its obviously detrimental to the overall cell chemistry and life of the battery.

Moxi

[Moxi]

ha ha like wot JB said.

Moxi

[spread-tee]

Thanks chaps, every day's a school day trouble is, so much to learn from this forum my head needs clamping

Desp

[Joeboy]

That's the cell balancer mounted. Quite happy with the look of it. Might just measure up and solder on the extension wires , nah! That's mental....

Wondered if I can purchase a 48vdc pc case type fan with a built in thermostatic setting on a variable knob? Might be worth drawing cold air from garage door side and actively pushing it across the top.of the hybrid inverter, charge controller and balance board? Will see how it all ramps up.once it's live.

Used thick black polythene sheet cut small and solder ironed thru for a hole. 8 of these isolating board nicely. Will use the same polythene sheet for the separators between the batteries. Using all the bits n Bob's from stock that I can, all the way down to single screws.

[Caesium]

Just cutting out some ply for my clamping system.. were you surprised how *small* these things are Joeboy? I've double and triple checked, hope I'm looking at the right datasheet Batteries are 207x173 so I've made my 6 boards 255x173.. 5 batteries clamped between each set.

Sit them sideways like you are I think then stack them on top of each other, with board jutting out front and back for some rods and bolts. Probably a cutout or two in the front to get a cable in so its flush with the terminal bolts..

Just can't get over how small these boards look! I'm sure I've got it wrong!