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4.5kw powerwall
#1
This is my first 18650 powerwall.
13s 20p, total 260cells, 54.60V fully charged, 20A BMS, capacity 1560Wh X3.
Everything is soldered with 60/40 fluxed lead, last block is with spot welded tabs and then soldered.
All controllers are identical and in and out tabs are parallel.

    
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#2
Congratulations!
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#3
why 13s and not 14s?
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#4
You posted a nice picture of the plus side, could You show me how You did the minus side?

Best of luck with Your build. Smile

ChrisD
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#5
(01-09-2020, 08:45 PM)barry Wrote: why 13s and not 14s?
To save inverter, inverter starts beeping on a 14s fully charged cells. When I make bigger project with batrium I make 16s 3.90v cell charge limit.
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#6
(01-10-2020, 12:39 PM)Lithiumseller Wrote:
(01-09-2020, 08:45 PM)barry Wrote: why 13s and not 14s?
To save inverter, inverter starts beeping on a 14s fully charged cells. When I make bigger project with batrium I make 16s 3.90v cell charge limit.

What is considered full voltage? 4.2V/cell? If the inverters max voltage is 56V, then 4.0V/cell would be great for the cells.
However, if the inverters discharge voltage is low enough, then you might be ok either way. At 3.2V/cell, minimum discharge would be 41.6V cutoff. Even 3.4V/cell would be acceptable, 44.2V.

Remember, just dropping top cell voltage from 4.2V to 4.1V can extend the life of the cells by hundreds of cycles. Dropping to 4.0V/cell could add over a 1000 cycles to the total life span. Granted, not knowing how many cycles they have already been through, this makes an impact overall. However, adding 100's on top of any previous is great. Unless you fully drain and recharge every 24hrs, a cycle could be 2 or 3 days, depending on depth of discharge.
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#7
(01-10-2020, 09:12 PM)Korishan Wrote:
(01-10-2020, 12:39 PM)Lithiumseller Wrote:
(01-09-2020, 08:45 PM)barry Wrote: why 13s and not 14s?
To save inverter, inverter starts beeping on a 14s fully charged cells. When I make bigger project with batrium I make 16s 3.90v cell charge limit.

What is considered full voltage? 4.2V/cell? If the inverters max voltage is 56V, then 4.0V/cell would be great for the cells.
However, if the inverters discharge voltage is low enough, then you might be ok either way. At 3.2V/cell, minimum discharge would be 41.6V cutoff. Even 3.4V/cell would be acceptable, 44.2V.

"Remember, just dropping top cell voltage from 4.2V to 4.1V can extend the life of the cells by hundreds of cycles. Dropping to 4.0V/cell could add over a 1000 cycles to the total life span. Granted, not knowing how many cycles they have already been through, this makes an impact overall. However, adding 100's on top of any previous is great. Unless  you fully drain and recharge every 24hrs, a cycle could be 2 or 3 days, depending on depth of discharge."

I use this bank as ups for LiitoKala Lii500 chargers, 300w charger is constantly charging battery bank, every 8 hours voltmeter drops to 70%, so only a little discharge, not full discharge. This is only temporary solution until this spring, when I finish 16s powerwall EASUN solar 5000w inverter and some thousands of cells, with batrium limited 3.9 or even 3.8v cell.
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