PINNED - Lithium battery conversion/info

[Scooterman]

And you got the links and bolts too

It depends . Can't know the distance between holes yet , insulation too.
May buy you copper bars and a punch .

Okay Shirley understood, whatever you think best

Btw I have got these hole punches 3mm-8mm

I've used them for thick leather and drinks cans (for making shims). But I'm not sure if they would work with copper bar, I suppose it depends on how thick it is? But they're not as sharp as they once were.

Also insulators Shirley I was thinking of making my own but I think the ones you can will be better.

I''ll leave it to you to decide what's best.

[Scooterman]

How much to UK for 16, no bars, total cost?
I may order 16 of these in place of the 176Ah ones?

Found this

Yes that's them . Shirley quoted about £952 landed, but that was before xmas so the price may have gone up I don't know?

He wanted to test 4 cells first so I sent payment for them and will pay him whatever the balance is when he requires it (plus extra for his time and effort).

But he's getting me some other bits and bobs as well so it's best if I leave answering your question to him. I wouldn't have had the confidence to buy cells myself direct from China, plus I didn't really know what other bits I needed to go with them, so Shirley is helping me out with all that. He's been really good

[shirley_hkg]

How much to UK for 16, no bars, total cost?
I may order 16 of these in place of the 176Ah ones?

No rush.

Just hooked up PL8 to my chair. Will do a initial charge @3.605V , then a fast discharge @3.00V .

Wait for my results first .

Good luck to Scooterman. It's his money .

[Scooterman]

Thanks Shirley I’m confident they’ll be good, they look nice anyway

[Burgerman]

At 3V you will get approx 78Ah. Per cell.

[shirley_hkg]

At 3V you will get approx 78Ah. Per cell.

Any voltage would you suggest ?

[Burgerman]

I usually set 2.9 if I care about cells. But a full capacity test would need a 3.650V charge to 0.06A or less, and a warm room, and discharge to 2.5V which isn't very good for the cells.

So if you get 80Ah per cell, or more, to 2.900v per cell on a low C discharge then thats all you can expect!

[Scooterman]

I've thought of wiring a diode into the +V line.... It would block charging voltages from the outside, but still give nominal 24V (less the diode drop) power as a supply for whatever....

I haven't tried it, but presumably this would also still allow programmers that go through the XLR plug (i.e. Pilot+) to work....

ex-Gooserider

That is a clever idea, there's no way I'd have thought of that, thanks. I'm not ready yet to do the conversion yet, but I have some 24V 10A diodes so I will have an experiment to see if it works, and the s-drive dongle that Woody made still works.

Or alternatively it may be better to just remove the XLR socket and replace it with one of them 24V to USB panel mounted outlets.
But that's a little way off yet.

[Burgerman]

You will want 36V or greater diodes, really. For a little headroom. We charge at 28.8 to 29.4V

[LROBBINS]

For anyone planning to punch holes in copper connectors:

It's very easy to anneal copper, and it is then easy to cut. Just heat to red and let it cool slowly in air. It will eventually return to a harder state, more quickly if work-hardened, but is quite soft in the annealed state.

[Scooterman]

You will want 36V or greater diodes, really. For a little headroom. We charge at 28.8 to 29.4V

Ah! Thank you I didn’t think of that. I found the order for the ones I’ve got here:

[Scooterman]

For anyone planning to punch holes in copper connectors:

It's very easy to anneal copper, and it is then easy to cut. Just heat to red and let it cool slowly in air. It will eventually return to a harder state, more quickly if work-hardened, but is quite soft in the annealed state.

thank you Lenny. I’ve filed that away in my brain for future use

[shirley_hkg]

At 3V you will get approx 78Ah. Per cell.

Put in 81,230 mAh , @3.615V .

Sit there for 2 hrs , and is now @20A discharge .

Things are looking good ! ! !

[Scooterman]

Things are looking good ! ! !

[shirley_hkg]

But a full capacity test would need a 3.650V charge to 0.06A or less, and a warm room, and discharge to 2.5V which isn't very good for the cells.

So if you get 80Ah per cell, or more, to 2.900v per cell on a low C discharge then thats all you can expect!

IMO, they are good enough, so stopped early to avoid unawarded damage to Scooterman's property.

Cell voltages were still under load . Up a little bit after discharge stopped .

I want 16 of them for myself .

[Scooterman]

That's really good Shirley, I am pleased

Thank you for all your work (ordering and collecting the cells) and for testing them, plus making the cables, etc. As I said before I couldn't do this conversion without your help.

Let me know when you need the money for the rest of the cells and other bits and bobs. I can pay you in instalments or a lump sum, whichever you prefer.

[foghornleghorn]

How accurately do the dimensions match the LF90 data sheet? I am very tight on space but may be able to fit some of these as (two sets of) 7 together + 1 down the edge.

lf90-cells.jpg (182.95 KiB) Viewed 6978 times

[Scooterman]

How accurately do the dimensions match the LF90 data sheet? I am very tight on space but may be able to fit some of these as (two sets of) 7 together + 1 down the edge.

You probably know, but you have to allow a little but extra for insulation. But I think Shirley can get some 1mm thick pre-cut insulting sheets.

[Scooterman]

Meant to say insulating, not insulting sheets

[Burgerman]

viewtopic.php?f=2&t=1813&start=3810#p130884

Posted full measurement specs here -- see pdf file. viewtopic.php?f=2&t=1813&start=3810#p130884

Add 9mm width for 8S (1MM sheet between each cell) doing it your way.

But you need SIXTEEN, and fitted the other way around to get the 180Ah capacity. That should fit where grp24 came out.

ITS 2 wide, 130.5 x 2 = 261 + 3x 1mm sheet for insulation, = 264 total width,
And 4 deep each battery, or 8 deep total. Thats 37mm x 8 = 296 depth. + 9mm insulation. So 306 total.

Since a stock grp 24 is 171 x 260mm, these should fit.

[foghornleghorn]

This way round?

lf90-cells-2.jpg (182.39 KiB) Viewed 6975 times

I've had 2 different people measure for me last summer and space is 260 wide x 355 front to back. Can't go wider without crashing into moving parts.

[Scooterman]

I think you might be a bit tight on the width. T

From memory the cells are 130mm, so x2 = 260mm + 3mm of insulation

[Burgerman]

You measured 260.
WITH insulation, this is 263 or 4mm so just 4mm extra? Thats the thickness of a bit of cardboard. Or a hard book cover.

Are you sure it wont stretch a fraction if an inch? 1/8th of an inch? Use .5mm insulation and then its inder an 1/8th of an inch extra!

If so you can get a useful 180Ah AND another 10Ah on top sat in the gap left using these https://www.alibaba.com/product-detail/ ... 05204.html

So 190Ah with 8mm to spare! What actually stops the needed 3 to 4 mm fitting? Anything a little adjustment will fix?

Your original way will also fit, just. But less elegant.

[foghornleghorn]

Don't want to skimp on insulation, this isn't a chair for smooth tarmac and will need to survive rough surfaces.

Width limit is the gearboxes go up and down. Only way to get them further out looks like cutting the frame centrally and widening it, but then will need a new seat frame, and the plastic shroud will need surgery too as chair needs to be weatherproof. Would rather avoid all that and also feel it will cock up the handling plus going to find it doesn't fit through tight gaps that are already a squeeze.

[foghornleghorn]

On top of this I still need to add ballast somewhere so I don't tip over.

[Scooterman]

Drink more

[Burgerman]

Cut a 260 x 340mm lump of sheet lead that is 12.5mm thick. (1/2 inch sheet). Or 2x 1/4 sheet. Or 4x 3mm 1/8th sheet. Thats 30lb. Drop it onto the battery compartment floor. And because its lower than your lead bricks it affords the same CG or stability as before.

https://ultraray.com/calculator/rectangle

Depending on how flush you are you can do the same with gold. But it can be only 2/3rds the thickness.

[foghornleghorn]

£25 of lead or £450,000 of gold. Difficult choice!

[Scooterman]

Could you bust open a couple of old batteries and use the lead plates?

[Burgerman]

If you are Bezos, then its easy. Buy the Gold. It will go up in value, tax free. And the battery sits 4mm lower.