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LiFe P04wall
#1
Lifepo4 cells recovered from electric bikes or 12v batteries 

Tested and tested with OPUS 0.5A 
Cells with Ah between 0.9 and 1.6. 
Average well above 1Ah but will be considered as such. 
Nominal voltage : 3.2V 
Full charge voltage 3.65V 
Set maximum effective charge voltage 3.5V 

Inverter 24V 
Charge controller for lead (very lead-like curves) 24V 

Test system : 
Balanced charging with ISDT T8 loader/bms 

Discharge with inverter and 250w sampling to verify the yield of the system in "average" conditions 

BMS: 
1S balancer on single series with discharge of 1.6A max at 3.6V 

In test also 16S balancer (in case of 48V) that will be used at 8S only. 

Future test of a real BMS with lower balancing currents but completely "different" parameters. Maximum charge and discharge 20A. 


Accumulator configuration : 8 Series 80 Parallel (8S16P5P) 

5P: 
The parallels are made by spot welding 5 cells with cheap welding machine bought in Germany. 


16P: 
Each parallel packet has a fuse on the positive, which in case of absorption/erogation of more than 3A jumps (fastblow) 

8S: 
S are mixed together with the parallel of the 16 blocks of 5 cells. 

To do:  8 packs like this  when time will allow. 

Accumulated energy : 
80ah x 25.6V = 2048 Wh 
Maximum project peak : 
3A * 16 *25.5V = 1.22 Kwp 
Expected peak at full speed for each package : 
3000w / 8 = 375w 

Parts: 
Holder 4x 18650 =32 pieces 
Fuses 3A = 144 pieces 
Cable 4 Msq = at will 
Nickel strip : 30 meters 
Hours : various 


Redpacket and Korishan like this post
Building Lifepo4 Powerwall - atm 1400 cells growing

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#2
384+ cartridge (5P) - overall average 1080 mAh per cells
  


now is time to build firsts 6 kWh

Code:
mAh     pcs    ah    wh
3000    15    45    144
4000    40    160    512
5000    151    755    2416
6000    149    894    2860.8
7000    40    280    896
            
Avg mAh |Tot. Pcs |Tot. Ah    |Tot. Watt/H
5.403    |395      | 2134    |6828.8
Avg Cells            
1.081
Building Lifepo4 Powerwall - atm 1400 cells growing

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#3
Nice!

Note that you wrote BMS but then you talked about balancers. Its not the same thing. A BMS protects and notifies as well so you should divide that upp. You need cell level protection in first hand not balancing. And most likely not 1.6A balancing. When you need to balance that much you have an issue. With that said its not bad to have the capacity.
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Current: 10kW Mpp Hybrid | 4kW PIP4048 | 2x PCM60x | 83kWh LiFePo4 | 10kWh 14s 18650 |  66*260W Poly
Upcoming: 14S 18650~30kWh | Automatic trip breakers, and alot more
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#4
yes Daniel, you're right.

i haven't updated first post.

i was trying a balancer, then i've changed my mind.

actually thinking about a diy balancer /monitoring cells and then some kind of safety.

in first pic my thermal cam Seek Reveal

i have i think around 300/400 kg of lifepo4 to open test and assemble... but it's a long work
Building Lifepo4 Powerwall - atm 1400 cells growing

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#5
How do you know they're all LiFePo, some cells seem to have very little information printed on them and look like "chinese" Li-Iions I found in generic Laptop packs.
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#6
(05-02-2019, 07:28 AM)emuland-metroman Wrote: 384+ cartridge (5P) - overall average 1080 mAh per cells
  


now is time to build firsts 6 kWh

Code:
mAh     pcs    ah    wh
3000    15    45    144
4000    40    160    512
5000    151    755    2416
6000    149    894    2860.8
7000    40    280    896
            
Avg mAh |Tot. Pcs |Tot. Ah    |Tot. Watt/H
5.403    |395      | 2134    |6828.8
Avg Cells            
1.081

on that third picture I see a cell with ICR 18650 3.7V on it, I think they might be Li-ion and if so, you're testing could be totaly wrong
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#7
nope. only dumb label put from Sellers.

valence saphion 3.2v laserwrited

https://secondlifestorage.com/t-Lishen-L...ifications

https://secondlifestorage.com/t-Valence-...ifications
Building Lifepo4 Powerwall - atm 1400 cells growing

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