Rolf Bartels

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

I paid for the cells, nothing for free today, even though the ewaste companies
would have to pay to dispose them, but the total cost was about R20K, with all connectors, shunts, change over switches, fuses, mounts and BMS

I am using the DIYBMS from Stuart Pittaway, search youtube for diyBMS and his name 
there is also a forum here DIYBMS v4 - Hardware / diyBMS - OpenEnergyMonitor Community

I have just ordered from JLCPCB the newest one, have to order 5 at a time, which is why I'm selling some.

Ideally, but not really, I would say the 80% of the cells are 2200-2800mah, and with 80 of them in a pack ea. cells only has <100mah max draw from them.
Check this site out this is where I got all my information from.
Second Life Storage & Solar
Even just 1 row of 14 packs is big enough that the draw from the draw on a per cell basis would be <300mah at max current.
This site is what I used to work out which cells belong where.
rePackr - 18650 pack builder
there is a excl version of this that I used so I could save it and work with it over time.
These used cells have at least 80% capacity left, so basically a 3000mah cells would give me at a min. 2400mah.
Laptop batteries are discarded when the stop working 90% of the time it's just 1 cell that failed and so the whole pack become un-useable until someone like me comes along and strips and tests them, Each cell is connected to buzz bar on each pack with 2a fuse wire, so if a cell decides to go nuclear the fuse will pop and it won't pull the whole pack down.


 

Everything except Aircons, Pool Pump and Geyser Element, but the Geyser is Solar so the element never really works, I have 7KW solar 4kw is gird tied with micro inverters and 3kw is connected to the Solar inverter which is also connected grid tied.

I have run 3days without Eskom and it was raining
.

Now It was a process !!!!!
Procured old laptop battires, (6000-7000) cells ( 2000 odd laptop batteries)
Stripped and cleaned them
Tested and discarded all 0v cells
Charged every cell to 4.2v and left on a shelf for 6 weeks
Tested each cell after the 6 weeks, and any cell under 4.05v I discarded
Charged again and discharged at 1A till empty and chargerd again, I avg the discharged mah and charge mah, any thing under 1800mah I discarded
Palced on a shelf again for 6weeks
After 6weeks anything under 4.05v I discarded the rest are good for use
Then used some software called repacker and entered all the cells into this, I configured it to 80cells per pack, it calculates which cells need to go into which pack so that the biggest delta between the lowset and highest pack is 0.5a. each 80 cell pack is just over 180a.
Cells ranged from 1800mah to 3200mah but the avg is about 2300mah
 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Ideally, but not really, I would say the 80% of the cells are 2200-2800mah, and with 80 of them in a pack ea. cells only has <100mah max draw from them.
Check this site out this is where I got all my information from.
Second Life Storage & Solar
Even just 1 row of 14 packs is big enough that the draw from the draw on a per cell basis would be <300mah at max current.
This site is what I used to work out which cells belong where.
rePackr - 18650 pack builder
there is a excl version of this that I used so I could save it and work with it over time.
These used cells have at least 80% capacity left, so basically a 3000mah cells would give me at a min. 2400mah.
Laptop batteries are discarded when the stop working 90% of the time it's just 1 cell that failed and so the whole pack become un-useable until someone like me comes along and strips and tests them, Each cell is connected to buzz bar on each pack with 2a fuse wire, so if a cell decides to go nuclear the fuse will pop and it won't pull the whole pack down.


 

Everything except Aircons, Pool Pump and Geyser Element, but the Geyser is Solar so the element never really works, I have 7KW solar 4kw is gird tied with micro inverters and 3kw is connected to the Solar inverter which is also connected grid tied.

I have run 3days without Eskom and it was raining
.

Now It was a process !!!!!
Procured old laptop battires, (6000-7000) cells ( 2000 odd laptop batteries)
Stripped and cleaned them
Tested and discarded all 0v cells
Charged every cell to 4.2v and left on a shelf for 6 weeks
Tested each cell after the 6 weeks, and any cell under 4.05v I discarded
Charged again and discharged at 1A till empty and chargerd again, I avg the discharged mah and charge mah, any thing under 1800mah I discarded
Palced on a shelf again for 6weeks
After 6weeks anything under 4.05v I discarded the rest are good for use
Then used some software called repacker and entered all the cells into this, I configured it to 80cells per pack, it calculates which cells need to go into which pack so that the biggest delta between the lowset and highest pack is 0.5a. each 80 cell pack is just over 180a.
Cells ranged from 1800mah to 3200mah but the avg is about 2300mah
 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Ideally, but not really, I would say the 80% of the cells are 2200-2800mah, and with 80 of them in a pack ea. cells only has <100mah max draw from them.
Check this site out this is where I got all my information from.
Second Life Storage & Solar
Even just 1 row of 14 packs is big enough that the draw from the draw on a per cell basis would be <300mah at max current.
This site is what I used to work out which cells belong where.
rePackr - 18650 pack builder
there is a excl version of this that I used so I could save it and work with it over time.
These used cells have at least 80% capacity left, so basically a 3000mah cells would give me at a min. 2400mah.
Laptop batteries are discarded when the stop working 90% of the time it's just 1 cell that failed and so the whole pack become un-useable until someone like me comes along and strips and tests them, Each cell is connected to buzz bar on each pack with 2a fuse wire, so if a cell decides to go nuclear the fuse will pop and it won't pull the whole pack down.


 

Ideally, but not really, I would say the 80% of the cells are 2200-2800mah, and with 80 of them in a pack ea. cells only has <100mah max draw from them.
Check this site out this is where I got all my information from.
Second Life Storage & Solar
Even just 1 row of 14 packs is big enough that the draw from the draw on a per cell basis would be <300mah at max current.
This site is what I used to work out which cells belong where.
rePackr - 18650 pack builder
there is a excl version of this that I used so I could save it and work with it over time.
These used cells have at least 80% capacity left, so basically a 3000mah cells would give me at a min. 2400mah.
Laptop batteries are discarded when the stop working 90% of the time it's just 1 cell that failed and so the whole pack become un-useable until someone like me comes along and strips and tests them, Each cell is connected to buzz bar on each pack with 2a fuse wire, so if a cell decides to go nuclear the fuse will pop and it won't pull the whole pack down.


 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Now It was a process !!!!!
Procured old laptop battires, (6000-7000) cells ( 2000 odd laptop batteries)
Stripped and cleaned them
Tested and discarded all 0v cells
Charged every cell to 4.2v and left on a shelf for 6 weeks
Tested each cell after the 6 weeks, and any cell under 4.05v I discarded
Charged again and discharged at 1A till empty and chargerd again, I avg the discharged mah and charge mah, any thing under 1800mah I discarded
Palced on a shelf again for 6weeks
After 6weeks anything under 4.05v I discarded the rest are good for use
Then used some software called repacker and entered all the cells into this, I configured it to 80cells per pack, it calculates which cells need to go into which pack so that the biggest delta between the lowset and highest pack is 0.5a. each 80 cell pack is just over 180a.
Cells ranged from 1800mah to 3200mah but the avg is about 2300mah
 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring

 

Just wanted to show case a small Powerwall I build using 18650's
Built this bank on 2020, been running for 3yrs, and so far only had only pack have an issue with 1 x 18650 self discharging which I changed out.

Summary:
3360 x 18650's
3 x 9.5kwh banks = 28.5kwh 
DIYBMS Monitoring