PINNED - Lithium battery conversion/info

[Burgerman]

If they were 3C then you CAN take 300A from them. Max. But they will last a month to a year if used daily maybe - thats a guess, too many variables.
If they are 3C and you take 100A from them, (a third of their max rating) maximum, they will last years.

But in your lightweight case, stripped down chair, light user, you may be OK. Because battery amps are usually much lower than motor Amps.

But I thought these were 1C cells, with only 3C pulse rating (a second or so).

[Irving]

Can you give the overall dimentions of the pack as seen W x L x H?

Actually that should read 200Ah, 12V as its a single lead brick box right?

Looks like this:

[Scooterman]

If they were 3C then you CAN take 300A from them. Max. But they will last a month to a year if used daily maybe - thats a guess, too many variables.
If they are 3C and you take 100A from them, (a third of their max rating) maximum, they will last years.

But in your lightweight case, stripped down chair, light user, you may be OK. Because battery amps are usually much lower than motor Amps.

But I thought these were 1C cells, with only 3C pulse rating (a second or so).

That's excellent advise BM, I will definitely look into that before the time comes to order.

Without wishing to appear sychophantic I do heed your advice. I've learnt the hard way not to dismiss it lightly. But sometimes I have a plan/idea in my head and just have to carry it through.

Without wishing to go off-topic remember that trailer I made/adapted for my scooter? I ended up selling it. Pain in arse it was. Heavy, badly engineered (not my bit, the wobbly chinese build/design wheel axle pins and tow hitch parts). And at speed it used to snake/vibrate all over the place and pull the back of the scooter about, I hated towing it. But I had a bee in my bonnet that a trailer would be great, it wasn't!

[Scooterman]

goodpost
EVE-LF90 , Rated --- 3C (5C max) ; IR @ 0.5mΩ .

Are the 105s lower c-rate than the 90s?

[foghornleghorn]

EVE-LF105 Product Specification

[Burgerman]

Yes. 1C max continuous (more than a second to all day) better less, like .3c to .5c if you want them to last and not swell. Remember that a 90A controller can take 2x 90 as you climb a ramp or steep hill for a short period.

3C pulse or very short term absolute max but voltage will drop a lot. And the cells dont like it.

If you fit 210Ah, then this obviously isnt a problem, as this doubles the current capability too.

[Scooterman]

Mmmmm yes I see what you mean I’ll have a think about it.....

[Scooterman]

I tried the tong tester, but no good it only measures AC. Another eBay listing coming up

[Scooterman]

Is this the same cell and supplier people are using?

https://www.aliexpress.com/item/3304892 ... b201603_55

[Burgerman]

Different supplier, seems expensive. https://www.aliexpress.com/item/3305421 ... 31d55a755f you need 16...

[Scooterman]

[Scooterman]

Has anyone built a lifepo4 pack using cells with an M4 threaded hole?

If so how did it go?

[Burgerman]

I will be doing. And it will go well. Because I have a feel for threads, and metals. And because I will permanant threadlock some threaded studs into every one using all of the thread. Before ever attempting to do anything else. And then leave them to set hard for a few days. Then I will use small ring terminals, and nylock nuts without washers. And the CORRECT level of torque by feel, to make sure they are assembled clean and oxide free, whilst not overtorquing the small 4mm threads in soft alloy. And certainly wont use bus bars. And will only use 6mm or 4mm cables if 16 cells other than the ones going to the chair.

[Scooterman]

Do you prefer to go by ‘feel’ rather than use a torque wrench? I’ve not got a TW but you must have one BM?

[Burgerman]

I do, but my fingers are better. I know what is enough, and how much is needed, and can feel when I am gone to the safe limit. A number doesent tell you that. Unless you have somehow got the right number from somewhere?

[shirley_hkg]

Has anyone built a lifepo4 pack using cells with an M4 threaded hole?

If so how did it go?

https://www.wheelchairdriver.com/board/ ... start=5190

[Scooterman]

Thanks Shirley, I've got a memory like a sieve

Did it all go okay with the M4 threads and studs/bolts?

No probs with threads stripping in the aluminium???

Are the M4 threaded holes the same depth as the M6 threaded holes, i.e. 5mm-6mm deep?

[Scooterman]

https://www.aliexpress.com/item/4000224 ... 0224208689 + ultra lightweight chair and rider =

and 8 cells so less

[Burgerman]

But those are a difficult size that does not fill the battery compartment? They are lower, mostly.

[Scooterman]

But those are a difficult size that does not fill the battery compartment? They are lower, mostly.

Oh

[Scooterman]

Shirley what's your opinion on Aliexpress lifepo4 cells?

I remember once reading in this forum that it was suspected that some sellers were cleaning up old cells, testing them, and then re-rating them at close to the tested Ah?

If the cells are new where does the Aliexpress seller store get the cells from? Are the seller stores manufacturers selling direct to public?

Or do the sellers buy large crates of cells at different Ah rating, then re-sell them to public in smaller quantities?

[Burgerman]

All of the above. And old cells. And warranty returned cells. And back door cells, and cells that failed to reach testing capacity or int resistance. And new, healthy quality cells.

[shirley_hkg]

It used to.

With surge of supply , decent quality stuff are easy to find.

They make quite some profit at this price tag already . Together with refund policy of AliExpress, most sellers don't want to bother with complain.

You will get 90% of rated capacity.

[Burgerman]

Why?
Is that because they exadurate the ACTUAL rated capacity? Or because cells ere old, or used? Or because they come from batches of failed cells?

Why do all these cells from so many suppliers all look the same, whey no lables, manufacturers, known specs, different capacities from identical looking cells etc?

For e.g. When I buy an Odyssey, its obvious. I can see serial numbers, trace back to a manufacturer, check build batch, check warranty, download DETAILED specs and other data. Why are all these lithium cells so 'anonymous'??

[shirley_hkg]

One A grade cell costs £70 brand new. Itsn't difficult to understand , is it ?

[Burgerman]

So... How do we know, that we are getting an a grade cell? Or if its new? Or if its direct from a manufacturer or RELIABLE reseller?

[shirley_hkg]

Don't know neither.

Nevertheless, you'll have your money back.

[Burgerman]

How can we tell that the CORRECT capacity of a new cell is 105, 100, 90, 80?

How do we know that the 105Ah cells are not used and now are 90A?

If I buy a headway cell, rated at 12Ah, I get 12Ah or more on test.

[steves1977uk]

I want to buy 16 105Ah cells, but I'm wary about buying from sellers from Aliexpress as I don't want returned/used cells. So where do we buy brand new ones from Shirley?

Steve

[shirley_hkg]

One A grade cell costs £70 brand new. Itsn't difficult to understand , is it ?

EXCLUDING SHIPPING.