LiFePO4 cells, where to buy?

[markz]

I've been looking at these pouches. Can I just solder onto the tabs?
Has anyone else bought ANY cells from them, and what was the throw-away rate?

High C-Rate 10Ah LiFePO4 Cells
https://bmsbattery.com/ebike-battery/625-high-c-rate-10ah-lifepo4-cells-battery.html

Condition New

High C-Rate 10Ah LiFePO4 Cells.

More info

High C-Rate 10Ah LiFePO4 Cells

1. Nominal Voltage:3.2Volts.
2. Dimension: 8.4x60x260mm
3. Capacity: >10Ah.
4. Maximal Charge Current: 2C(20Amps).
5. Maximal Continuous Discharge C-Rate: 5C(50Amps).
6. Maximal Discharge C-Rate: 10C(100Amps).
7. Overvoltage Protection: 3.65±0.05Volts.
8. Undervoltage Protection: 2.0Volts.
9. Lifecycle: 2000Cycles.
10. Weight: 300Grams.
11. Impedance: ≤8mΩ.
12. Chemical: LiFePO4.

 

[riba2233]

Samsung 30Q are better choice, similar or lower price, lower IR, much higher energy and power density, and muuuuuch higher quality.

You can solder to tabs, but you shouldn't. Also pouches are very fragile, while cylindrical cells are robust.

 

[markz]

Whats the cycle life of Samsung 30Q?

$6 a peice delivered from here https://www.fasttech.com/products/0/10002357/2363400-authentic-samsung-inr18650-30q-3-6v-3000mah
15Acont though. So $420 72V 12Ah 60A or $360 for my needs 72V 9Ah 45A
or $330+$100s/h=$430 and 50Acont from shady bmsb at ~73 10Ah. Thats unknown too, who knows what your going to get.

Yeah, but each and every time I try and search for a cycle life from Samsung, Panasonic, Sanyo etc, I get numbers like 300-500cycles maybe 1000 if you treat them extremely nice.

 

[riba2233]

Its 15 a per cell! So 45 if you have 9 ah or 3 cells in parallel.

 

[markz]

Ah yes yes I keep forgetting that. 15Acont. per cell. More then enough. 5C for 30Q. 1A per cell = 0.333C which would mean dramatic cycle life increase.

So how are you suppose to connect a conductor to the pouch flaps?

 

[riba2233]

Probably some special spot welding or bolting.

 

[markz]

Yes I can buy 30q's cheap, delivered within 2-3 weeks from China. But the ~300 cycles is not worth my money. That in less then a year, ~6-8 months I buy new batteries.
This is why I am seeking LiFePO4. Same source sells these but 600mAh cans.

Headway Headquarters is priced high.
Could buy genuine Headways from bmsb, I guess at $16, $19 and $24 per can.

This just came online today from BMSB. It looks promising for a purchase.
https://bmsbattery.com/ebike-battery/756-lifepo4-18650-battery-cell-32v15ah-battery.html
Specs
http://www.master-instruments.com.au/products/63683/IFR18650EC.html
http://www.master-instruments.com.au/cgi/ajax/get_file/63683/1
I priced mine out at $455 shipped for 12Ah and 74V. 5Acont. Weighs 42g
Safety specs looks encouraging.
This one shows a white wrapper and a blue wrapper.
http://bbrpower.com/Li-ionLiFePO4-Single-Cel/product_62.html
$3.50 per at http://www.batteryspace.com/lifepo4...rate-4-32wh-ul-listed-un38-3-passed-ndgr.aspx
http://www.batteryspace.com/prod-specs/919-LFP-18650-1500.pdf
View attachment 1

So there is a $90 difference between BMS Battery (Cheaper) in China and AA Portable Power Corp aka BatterySpace.com (More expensive) They have offices in USA and Japan but

Two assembly production lines in USA for small, urgent custom orders.

In 2014, we set up our own UN38.3 Safety Testing Lab and can provide UN38.3 test service to our customers now.

Which would you choose?
Whats the delivery speed of these 3 shipping methods?
Cant use UPS, only FedEx. So its coming from most likely Cali, to Alberta Canada. Shouldnt take long at all. $140 difference now.

Rated Cap 1C
Capacity measured with discharge current of 1C with 2.0V
cut-off voltage after the standard charge.
≥
1375mAh
Rated Cap 2C
Capacity measured with discharge current of 2C with 2.0V
cut-off voltage after the standard charge.
≥
1350mAh
Rated Cap 3C
Capacity measured with discharge current of 3C with 2.0V
cut-off voltage after the standard charge.
≥
1325mAh

Life Expectation
Test condition
：
Temperature: 23±5°C
Charge: 0.5C CC to 3.65V, and CV to 0.05C cut off
Discharge: 0.5C discharge to 2.0V
80% or more of 1
st
cycle capacity at 0.2C discharge of operation
≥
2000 times

 

[markz]

Well heck if I can get 1000+ cycles out of Li Ion cells that are rated at 10-20A, and I am only using tops 3amps. Then heck why not.
I just thought it was not possible. Perhaps their rated discharge for the Li Ion cells is obsolute torture.

 

[markz]

Are a123's lifepo4's?
How much are they?
I dont care what form factor they are.

 

[riba2233]

They are terrible, only 1.1 Ah at 3.2 V lol. Don't even consider.... I had one new cells, after one year of sitting, it showed 850 mah on 5A discharge, that's pathetic. Not to mention price, for same money you get cell with 3 times more capacity. We are talking about 3.5 Ah cells at 3.6 V

 

[riba2233]

Lifepo4 and especially NMC (konions) have worse calendar life than NCA chemistry. OP doesn't need some extra high C rate, even if he did, he can always chose 25R and have same performance but almost three times more capacity. Also, a123 18650 are not their production, it's outsourced, their cells are 26650 and are much better than their 18650, but still sad energy density and ridiculous price compared to new 18650 brand name cells.

LG MJ1 have 3.7 times better energy density but lower discharge, and Samsung 25R have 2.55 times better energy density with same discharge rate, and both have much better price and better calendar life. Safety is same as lifepo4.
You need to put all those volume and mass somewhere on the bike, you know that? With lifepo4 you get large heavy chunk on your bike that makes ride not smooth.

 

[riba2233]

Well tesla obviously uses high capacity and long cycle (calendar) life, don't they?

Here's the source:

[youtube]pxP0Cu00sZs[/youtube]


Also, good cycle life is worthless without good calendar life, and 250 cycles for 25R are in worst conditions, lifepo4 would also last short in same conditions.

 

[markz]

Very interesting video riba, I watched about 25 minutes of it. Some of it was over my head, but I could understand most of it.
I particularly like the graph that compares the inverse CE/CIE slope to Telsa, Volt, Nissan, Fiskar. Thats around 27:12 minute mark.

Also like the mention of heat. How long and slow in heat, kills. Fast and short in heat, is better.

 

[markz]

What would you consider "moderate draw"
What exactly do you mean hybrid?
Keeping all cells the same brand/Ah/V in a series, then another type in another series string, but paralleled, but keeping the total V the same?

 

[999zip999]

What is this for a Lyen 18fet 65amp controller and muxus 3,000 ?

 

[markz]

yes

 

[999zip999]

So what voltage. I would run 72v. The battery cost more then twice as much as your kit. It's best if you save your money battery and get a battery that will work with your setup. Plus monster controller, needs monster battery.

 

[999zip999]

Hybrid fire.
You need a really good plug and play battery. Or you will be buying a second battery real soon. There's no cheating it. A starter ebike is 750watt to 1,500 watt. Not 4,200 watt.

 

[999zip999]

E~trike he is having a hard time getting his head around a battery to work with his 65amp controller. Plus a plug and play battery with One bms, one charger is enough. It would be different if he had a 20amp controller. Mark you can't use a battery that can only put out 20amps for a controller demanding 65 amps. It will just die.

 

[markz]

I think I meant the battery cell itself spits out 20A not the entire battery package.

The part I think I was unclear about before, but I am certain I know now is, if I had twenty 18650-25r cells (20Acont - 50Amax for 5s) cells in series to make 72V and 2.5Ah, would that entire series circuit output be limited to 20Amax, 50Amax for 5s. As 400A and 2500A make no logical sense.

But I did notice myself swapping "battery" and "cell" terms loosely.

The a123 26650 look very interesting. The price for a new pack is pretty high. The a123's being sold in the Used section look better price wise. But there is no way in knowing exactly what the run time was on those. The guy in Poland selling Lithium 18650's look promising, but at a 55 day shipping period. I also found it interesting that Bosch and BionX used the V3 Lithiums. http://endless-sphere.com/forums/viewtopic.php?f=14&t=69207#p1045291

Its a learning curve for sure. Perhaps me being a cheap-skate is hindering the decision making process.

 

[999zip999]

72volt 18650 25r would be 20s ( s for series ). Or 20s x 4.2 volt = 84 volts fully charged for the bms. Now with 65 amp controller about 8 parallel for 20ah.or 160 cells. Depending on how you ride. A little extra ah will help the whole pack last. If you set your controller to 40 amp thru a cycle analyst this will save you money for less parallel cells and less watts available. Still running at 40a drains a battery fairly fast, draining a battery at 65 amps is a lot faster. Speed kills mileage.
A123 are great but heavy as where do you have room ? And how much you weight ?

 

[markz]

Yes, I am waiting, and I am learning. Value is what I want.
Sony Konion US18650-VTC4 are dirt cheap. But someone said something about NMC that I am trying to still figure out.
What interests me about these particular cells are not only the price, but the cells "Continual Discharge" rating of 30A! Slightly less capacity @ 2.1Ah.
Compared to others like the 25r at 2.5Ah, 20A but about $1 more per cell.

I did see Green Machine's ad, G.M. doesnt ship to Canada. G.M. has got some good battery products there, on his website, no doubt.

Battery space, without my stock plastic battery case, I got 4-3/8" (114mm) Wide, by 18"L (457.2mm) by ~6" (152.4mm) Height.
So 18.5mm diameter x 65mm length. I can fit 336 cells total in a space of 8 layers/cells high or 42 cells per layer.

100 cells of VTC4 in 20S5P get me 72V 10.5Ah @ 150Acontinuous for $375 <--150A!
100 cells of VTC4 in 20S4P get me 72V 8.4Ah @ 120A for $300 <--120A! - Not much range at all!

100 cells of PF in 20S5P get me 72V 15Ah @ 50A for $400 <--50A Maybe
80 cells of PF in 20S4P get me 72V 12Ah @ 40A for $320 <---40A to low!


100 cells of HE2 in 20S5P get me 72V 12.5Ah @ 100A for $450 <--100A Yes
80 cells of HE2 in 20S4P get me 72V 10Ah @ 80A for $360 <--80A Yes

I just got a bite on a pack of used a123's. I will go ahead with the purchase.
From what I read, these are awesome cells.
From my understanding they are 3.3V and 2Ah, so 22S is 72.6V and at 4P gives me 8Ah and 88 cells, with 8 left over.
Its low on the Ah, but I can always buy more, and for now this will be my backup pack to get me home without damaging my primary pack.

 

[999zip999]

So you have a spot welder ?

 

[riba2233]

I just got a bite on a pack of used a123's. I will go ahead with the purchase.
From what I read, these are awesome cells.
From my understanding they are 3.3V and 2Ah, so 22S is 72.6V and at 4P gives me 8Ah and 88 cells, with 8 left over.
Its low on the Ah, but I can always buy more, and for now this will be my backup pack to get me home without damaging my primary pack.

Yeah (actually 2.3 Ah, but when they are new), but double the weight and volume

 

[markz]

No sag.

We will see.

Im buying riba's spot welder.
Or can build a capacitor welder too, for cheap.