Cylinderical LiFePO4 cells?

[mannydantyla]

I'm researching battery cells for my vintage motorcycle conversion build, and it feels like every day I discover a new battery that is better in some way over the previous day's discovery.

Today, it is these cylindrical Lithium Iron Phosphate cells: https://www.alibaba.com/product-detail/High-efficient-48270H-3-2V-30Ah_62224576858.html?spm=a2700.details.deiletai6.5.241a545b37uqsb

So these may not be new but they're new to me and I have not seen anybody build with them them before.

Does anybody have any experience with these? The alibaba listing does not say the max peak and continuous discharge capacity and I would like to know that. It also doesn't say the dimensions [edit: I see it now. They're 48270, or 48mm x 270mm). I have Micah Toll's book on diy lithium batteries and he says that LiFePO4 cylinders are made by Headway in the 38120 and 40152 sizes, but the book is 3 years old now.

The reason I would want cylinders over prismatic cells is because I could built the battery pack into a custom shape. I want my battery box to be very asthetic. The cells also have bolts for terminals so installation will be much easier than 18650 ion cells. I would need 23 of them to get 72v. Here's my mockup: https://www.vintagehondatwins.com/forums/showthread.php?2054-CA160-EV-Conversion&p=21374&viewfull=1#post21374

Thanks!

 

[neptronix]

Those cells are listed as both being LTO and LifePO4 and the specifications are incomplete.
Strange that a supposed manufacturer of these cells does not know what they are selling.

I'd run like hell from this company.

 

[mannydantyla]

At that price, I wouldn't mind paying a little more for some assurance. Here's another source - https://www.batteryspace.com/lifepo4-40152s-cell-3-2v-15-ah-150a-surge-rate-48wh-with-6m-screw-terminal---un38-3-passed.aspx - but they're half as much capacity so I'll need twice as many. But look at that price! $40 each for a total of $1,840. The alibaba ones would only cost me $230. At that price maybe it's worth the risk.

 

[neptronix]

I believe batteryspace is a good vendor and those cells are likely 'headways' brand.

Just keep in mind that headways aren't much more energy dense than lead acid batteries. They hold a third of the energy of the best non-lifepo4 lithium cells on the market today.

Only a good choice if safety trumps all other considerations.

 

[Chalo]

Just keep in mind that headways aren't much more energy dense than lead acid batteries. They hold a third of the energy of the best non-lifepo4 lithium cells on the market today.

Only a good choice if safety trumps all other considerations.

Genuine Headway cells have better power density than most, with easier and higher-ampacity pack assembly methods than almost anything. They come in higher and lower energy versions, with inversely proportional maximum current ratings.

I haven't used Headways, but my own e-bike packs are made from automotive cells that sacrifice energy density for power density, ease of assembly, cycle lifespan, cost per kWh, and pack simplicity compared to 18650s. I wouldn't mind having more range or lighter pack weight, but I wouldn't want to trade off the qualities I enjoy now in favor of those things.

 

[neptronix]

Genuine headways come in at around 80whrs/kg ish. I had a pack with them a decade ago. The things are effin' huge. About 3 times larger than 150whrs/kg lipo. 200-250whrs/kg is the current standard for energy density.. so this is a far cry from good.
I literally just sent the pack to a recycler because it didn't even remotely perform up to the discharge spec either.

They're also rather expensive per whr.

I agree that a large pack with 18650s is a pain in the ass to build. Building a pack with 21700's cuts the number of cells needed in half. That's a good in between solution.

 

[john61ct]

The only cylindrical LFP worth a hill o' beans are A123

full stop

 

[Chalo]

The only cylindrical LFP worth a hill o' beans are A123

I just ordered some of those. Their energy density is pretty low-- even lower than the low energy density automotive cells I'm using now. But their power density is phenomenal.

They have the same problems as any cylindrical cells lacking threaded terminals, in terms of difficulty of assembly and being limited by their connections more than by their cells' capabilities.

 

[999zip999]

I was looking at these
https://batteryhookup.com/products/100-brand-new-lifep04-32650-3-2v-6000mah-cells
They also have the 8ah headway s at 16.00
Lifepo4 is big and heavy my A123 20 ah pack lasted 7 years 1480 charge cycles. No BMS just bulk charge.
I order a Samsung 40t 30 amp cell triangle pack 20s 6p. 180 amps on paper BT BMS

 

[Chalo]

I was looking at these
https://batteryhookup.com/products/100-brand-new-lifep04-32650-3-2v-6000mah-cells

I just last weekend helped a buddy build those into a 4S 2P replacement (with BMS) for a 7ah lead brick. No test or field results yet, but I'm confident they'll be an upgrade for his portable speaker.

 

[999zip999]

Lifepo4 is ez to use as 12 or 24 volt stuff as lipo 3s or 4s is tuff. Plus it has long life and is very safe. Yes it can still make fire.

 

[mannydantyla]

Thank you very much everyone. I have much to learn still.

 

[999zip999]

How about this
https://www.thriftbooks.com/a/micah-toll/2746669/

 

[mannydantyla]

How about this
https://www.thriftbooks.com/a/micah-toll/2746669/

I already have that book! Nearly finished reading it, lol

 

[Hosedragger]

I was looking at these
https://batteryhookup.com/products/100-brand-new-lifep04-32650-3-2v-6000mah-cells
They also have the 8ah headway s at 16.00
Lifepo4 is big and heavy my A123 20 ah pack lasted 7 years 1480 charge cycles. No BMS just bulk charge.
I order a Samsung 40t 30 amp cell triangle pack 20s 6p. 180 amps on paper BT BMS

I agree 100%. I use A123 ANR26650M1-B LIFEPO4 cells for EBike builds. They can provide 50A continuous per cell, 120A burst. Being LIFEPO4 chemistry they can be cycled 3x more than typical Li-Ion cells. Battery Hookup sells those cells around $1 each. They are listed as used but all the ones I have received test out better than 90%. You could build a 10Ah 72v 24s4p pack for a little over $100. It's a no-brainer. The only drawback is that they do take up some extra space since they are 26650 cells.

 

[john61ct]

The lower density is inherent in LFP chemistry.

The 26650 format in fact yields higher overall density than the same in 18650

 

[Chalo]

I use A123 ANR26650M1-B LIFEPO4 cells for EBike builds. They can provide 50A continuous per cell, 120A burst.

I recently bought some of those; I have yet to figure out how best to use them. I have seen their impressive cell specs, but I've never seen a plausible method for getting that amount of juice out of them. The modules I bought are fused 70A for a 4P pack, suggesting that their real ampacity (with an engineered bus) is something less than 17.5A/cell. For a homemade bus, I'd derate them beyond that.

Their energy density is low even by LiFePO4 standards.

 

[nuxland]

I made a 34s10p pack out of these A123 cells and can get over 600A out. And in a kart track my pack last about 10km (using 2kwh) of heavy acceleration and braking (i'm not using regen).
https://endless-sphere.com/forums/viewtopic.php?f=14&t=85912
Yes they are heavy (about 37kg is my pack and has 2,5kwh of energy).
My lipo pack that weights about the same 37kg has 3,5kwh of energy.

 

[john61ct]

Can't really compare the density of the tiny cylindricals to high Ah capacity prismatics where 40Ah per cell is considered small.

Getting all the pack capacity you need from a single string (no paralleling) is the ideal, but with most "bike" designs the weight and pack space dimensions are severely limiting.

My ideas for pure utility cargo / tandem design give more flexibility, but it seems most people are looking for greater speed, agility sporty "fun" factor.

Too bad no one makes cylindrical cells at say 7Ah with a round cross section of say 3-4" ?

I bet one day we'll see greater merging of the energy storage and structural framing tubes

 

[Hillhater]

.......
Too bad no one makes cylindrical cells at say 7Ah with a round cross section of say 3-4" ?

7Ah , with a 3-4” cross section ??..
.. that would only be about 5mm thick !
Very difficult to “wind” that jelly roll...and even tricky to make as a pouch !
Why would you want that format ?

A123 used to produce an 8Ah , 32mm dia , high C rate cell with screw terminals.....but no longer available.

 

[john61ct]

.......
Too bad no one makes cylindrical cells at say 7Ah with a round cross section of say 3-4" ?

7Ah , with a 3-4” cross section ??..
.. that would only be about 5mm thick !

Just spitballing, you including the protective outer shell?

OK then higher Ah, down to say 2" diameter.

Or a circular pouch format?

Whatever it takes to optimise for a single cylinder pack, no paralleling required, go to 20Ah by expanding the diameter, not length.

 

[Hillhater]

Ah ! OK i get where you are going now..
EG the new Tesla 4680, 25 Ah cell, if “stacked for 10s , 36v...would be 80 cm (32”) tall !! Impractical
But if that same capacity cell was bigger dia, the stack could be much shorter ...better for a bike
So.. 4080 cell has a volume of 133 cc for its 25Ah
That same “capacity/volume” would fit in a 6640 (66mm dia X 40,, tall) can. ..(think of those small 100gm Tuna cans !)
Then that 10s, 36v “stack” would only be 40 cm (16”) tall ...better ?
And a 20Ah version would be about 32cm (12.5” ) stack
Or, a 10 Ah version, stacked could be approx 16cm, (6”) tall

 

[john61ct]

Yep you got it.

Form factor adapted to optimise for the use case, rather than us "making do" with sizes that lead to poor finished-pack density