LiFePo4 18650

Wattsup

Wattsup

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Feb 19, 2017
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18650s in LiFe chemistry are expensive! LiFe is expensive in any format.

I wish used LiFe cells were easier to come by!

Do you think they will be used more in 18650 based applications. Laptops, power tools?

Given they are safer it seems to make sense. I relise the power densityis not as good as other Li Ion.

Annyone know what the highest Genuine capacity for LiFe 18650 is currently?
 
They are not as dense no and that is a big factor. The safety is not a major reason as of today and number of cycles arent either. They only base that laptop will last 2-3 years and a normal LiIon will do that easy.
Biggest I have seen is 1500. I have 1400mAh cells in my main battery bank
 
The highest non high drain cells that are in the 18650 format are 2000mAh cells.

However, in exchange for this higher energy density, you lose a lot on internal resistance, but keep the long cycle life of LiFePO4.
 
Hi guys,
Still looking / thinking about the ideal battery pack ... after exploring the Li-ion harvesting, I wanna double check the LiFePo4 path ...

If I understand correctly,
Pros
Greater cycle life (3000 at 80% dod, 5000 at 50% dod)
More constant discharge rate
Less battery sag
Safer
Faster charging time
Larger overcharge tolerance
Higher working temperature

cons
LiFePo4 is less energy dense
is hard to find / to harvest


I didn't add price in the pros/cons, because the price depend where you buy it !! AND I'm looking at the price per usable energy, and since LiFePo4 will last maybe 2 as long, and I can use more energy (deeper dod) then I'm not sure if I should put price per Wh in pros or cons

I had a look at the LiFePo4 on sell on Nkon, there is only one. There is only one : Heter 18650 3.2V 1400mAh - 10A LiFePO4
https://www.nkon.nl/sk/k/HTPFR18650-1400-3.2VEnglishSpecification.pdf

Do you know it ? have you tested it ?

I have checked the suppliers web site, they seems to be serious (at least the say there are only supplyer of chineese army, ...)

They sell on Alibaba : says $1.5 for 18650 rate 1500mAh LiFePo4 ... Asked for samples, and a quote for 600 and 1200 cells will see if I can beat the Nkon price at 2.75
 
Basically you understand it correctly, however it also depends on the cell. Not all LiFe cells are specced in the same way.

I think there is a misunderstanding though. If you want to go LiFe, why would you choose 18650s? 18650s don't have any inherent advantages when building a battery. Many people use them because they can be reclaimed from laptop batteries and so on (with usual LiIon 3.7V chemistries), but when you get new cells and want to build a bigger battery, then you don't use 18650s obviously.

Check for prismatic LiFe cells, for example from Winston or GBS. They make them from small (GBS 20Ah) to large (Winston 700Ah, maybe even bigger) capacities and it is much more convenient. Instead of handling hundreds of LiFe 18650s that need to be spotwelded or soldered you only need a few and they have screw terminals. Assembly time is reduced by 98% and you can get the cells for around 1.50 EUR per Ah.
GBS 20Ah = ~30 EUR
Winston 40Ah = ~60 EUR
Prices picked from a random shop in Germany. There is a company in the Czech Republic that is specilized in selling LiFe cells for any kind of customer project and they are even cheaper: https://www.ev-power.eu/
50 USD for the 40Ah Winston cell, but I think VAT comes on top of that, so maybe not cheaper after all, but probably about the same. They offer a huge portfolio though, lots of cells from different manufacturers in different sizes. Prismatic cells are definitely the way to go when it comes to LiFe cells.
 
DarkRaven said:
Basically you understand it correctly, however it also depends on the cell. Not all LiFe cells are specced in the same way.

I think there is a misunderstanding though. If you want to go LiFe, why would you choose 18650s? 18650s don't have any inherent advantages when building a battery. Many people use them because they can be reclaimed from laptop batteries and so on (with usual LiIon 3.7V chemistries), but when you get new cells and want to build a bigger battery, then you don't use 18650s obviously.

Check for prismatic LiFe cells, for example from Winston or GBS. They make them from small (GBS 20Ah) to large (Winston 700Ah, maybe even bigger) capacities and it is much more convenient. Instead of handling hundreds of LiFe 18650s that need to be spotwelded or soldered you only need a few and they have screw terminals. Assembly time is reduced by 98% and you can get the cells for around 1.50 EUR per Ah.
GBS 20Ah = ~30 EUR
Winston 40Ah = ~60 EUR
Prices picked from a random shop in Germany. There is a company in the Czech Republic that is specilized in selling LiFe cells for any kind of customer project and they are even cheaper: https://www.ev-power.eu/
50 USD for the 40Ah Winston cell, but I think VAT comes on top of that, so maybe not cheaper after all, but probably about the same. They offer a huge portfolio though, lots of cells from different manufacturers in different sizes. Prismatic cells are definitely the way to go when it comes to LiFe cells.
Click to expand...

Thanks for this detailed explanation and great idea because since I start from Zero (no solar power, no nothing) If I can spare the sorting, soldering, ... of the cells ! that could be great. So I will definitly have a look with this path. On the other end, investing 2000 in a battery bank without so much knowledge about battery management, battery charging, etc ... not so sure about it. I'm confident in my learning capacity, but I also know that making mistakes is part of the learning process, and a mistake on a 2000 battery bank :-/
So I might start of with harvested Li-ion small battery bank and solar panel settled on the ground+charger, make some error, play around, LEARN, and then go for the big battery ...
idk, I'll keep on thinking my project, share my idea / founding here, and we will see
 
frenchclem17 said:
Thanks for this detailed explanation and great idea because since I start from Zero (no solar power, no nothing) If I can spare the sorting, soldering, ... of the cells ! that could be great. So I will definitly have a look with this path. On the other end, investing 2000 in a battery bank without so much knowledge about battery management, battery charging, etc ... not so sure about it. I'm confident in my learning capacity, but I also know that making mistakes is part of the learning process, and a mistake on a 2000 battery bank :-/
So I might start of with harvested Li-ion small battery bank and solar panel settled on the ground+charger, make some error, play around, LEARN, and then go for the big battery ...
idk, I'll keep on thinking my project, share my idea / founding here, and we will see
Click to expand...

That sounds like a good plan to start with a small bank to learn with.

This is where buyingsome LiFe 18650s makes sense! To build a smaller battery.If you're considering a LiFe system, seems it wouldbest to learn with Life ;)

Sorry I didn't see what voltage system you want to build?

I'd also recommend CALB cells, it's what I have.

Feel free to check out my youtube channel :)

https://www.youtube.com/channel/UCBLudMLfVsDbumUJxWIz_WA
 
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