Home Powerwall with PCB V1.3

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karmi27

New member
Joined
Nov 5, 2017
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Hallo
im from south germany and this is my first post here!
Im building my own home powerwall with Jehus PCB boards.
first it will be round 10kwh couse i have now only 980 new lg mg1 cells.
here some pics of stand now!

used servercase

image_mtvnfi.jpg


3 x PIPs 5048 MG

image_ogsdfs.jpg



first 2 x 1kw modules

image_hiaorb.jpg



image_udfavc.jpg



other pics will follow

lg Karl
 
Looks great and Sevrusund Grss Dichfrom an Obersterreicher in Maine USA.

Wolf
 
Looking good, make sure to keep your stacks under 10 boards if you can to minimize voltage drop across the brass terminals, or thread some bare copper wire through the XT-60 terminal holes and solder to each board. What BMS are you going to be using with this system?
 
Thank you!
I will make it with 14 boards and every one will have 2 x 6mm2 cable with ringconnectors! it should handle ~ 50 amps!!
 
a BMS i dont use! i take an aktive balancer!
under - and overvolt my pips are controlling!!
i think that should work good!

image_tomrby.jpg
 
karmi27 said:
a BMS i dont use! i take an aktive balancer!
under - and overvolt my pips are controlling!!
i think that should work good!

image_tomrby.jpg
Click to expand...

Your pip's are controlling global under and over voltage not a single pack voltage, unless you have almost perfectly balanced packs or this balancer can handle a huge current while balancing, your packs will unbalance for sure, and nothing will stop charging or uncharging until the whole battery's voltage reaches the configured value.

I think a BMS is mandatory just for cutting if a single pack goes out of range.

Regards
 
Why should they go out of balance?!
My system is 14s70p and the balancer has over 1amp balance current! i only charge till 4.1v per cell and every pack will have the same voltage as the system voltage is!!
i think you have a litte thinking error!
 
Hi Karl,

Herzlich willkommen :)

Your build is looking like that what im going to do - nice!

Im also thinking aboutJehus PCB boards for my build - maybe you can take
more pictures of your work. Did someone use them with batrium bms?
 
Hallo und gre aus Solingen / Deutschland :)

Hello and greetings from Solingen / Germany

Nice construction with 3x220v three-phase current.

I would be glad about reports from you if that runs smoothly with the controller board of the loaders.

Gre Dirk
 
Not sure I understand the situation fully but let me try.
Jehu boards...look like 8s boards and stacks of those running in parallel?
Okay so you also have an 8s active balancer for each stack? This covers both over and under also?
In this case I am not seeing any reason for a bms.

On the other hand if you are dumping a solar load and not actively managing each cell and you also did not pack cells matching completely across all cells or have a cell that goes out. I can assure you there will be a pack that does not match.
 
TrustyFly said:
Not sure I understand the situation fully but let me try.
Jehu boards...look like 8s boards and stacks of those running in parallel?
Okay so you also have an 8s active balancer for each stack? This covers both over and under also?
In this case I am not seeing any reason for a bms.

On the other hand if you are dumping a solar load and not actively managing each cell and you also did not pack cells matching completely across all cells or have a cell that goes out. I can assure you there will be a pack that does not match.
Click to expand...

The boards are 7s configuration each. The pack +/- are connected in parallel with other boards in a stack, as are individual cells (balance leads). The BMS would protect in the somewhat unlikely case that an imbalance larger than the 1A balance current would be able to handle would cause some cell in the pack to exceed 4.2V or drop below 2.5V while the pack voltage was still within the pack level limits set by the charge controller/load.
 
Yeah I am not an expert but I do not think I understand why they would not get out of balance. Let me try drawing my idea of what would happen:
Pack 1 ++++++++ 29.6v
Pack 2 ++++++++ 29.6v
Pack 3 ++++++++ 29.6v
Pack 4 ++++++++ 29.6v
Pack 5 ++++++++ 29.6v
Pack 6 ++++++++ 29.6v
Pack 7 ++++++++ 29.6v
Pack 8 ++++++++ 29.6v
They are all balanced and everything is good but what happens if a cell goes bad.
Pack 8 ++++++-+ 25.9v
This will balance them all out to 25.9v and in a safe way to the other packs. But when you charge to 4.2v per cell or 33.6 each cell in pack 8 will have 4.8v per cell.

Maybe I am not understanding completely the setup.
 
TrustyFly said:
Yeah I am not an expert but I do not think I understand why they would not get out of balance. Let me try drawing my idea of what would happen:
Pack 1 ++++++++ 29.6v
Pack 2 ++++++++ 29.6v
Pack 3 ++++++++ 29.6v
Pack 4 ++++++++ 29.6v
Pack 5 ++++++++ 29.6v
Pack 6 ++++++++ 29.6v
Pack 7 ++++++++ 29.6v
Pack 8 ++++++++ 29.6v
They are all balanced and everything is good but what happens if a cell goes bad.
Pack 8 ++++++-+ 25.9v
This will balance them all out to 25.9v and in a safe way to the other packs. But when you charge to 4.2v per cell or 33.6 each cell in pack 8 will have 4.8v per cell.

Maybe I am not understanding completely the setup.
Click to expand...

If any cell goes short in a pack, it should blow the cell level fuse for the bad cell and likely the board level fuse for that board from the sudden inrush of current. So that last scenario shouldn't happen.
 
My configuration is 14s! so 2 packs in series with 50,4V!! all 10 packs ( 5 in series and 2 parallel ) are connected to the same one 14s balancer with extern voltage-display for every seriell cell!!
if on cell going bad, then the balancer will push the other series cells more than the orher!
i have all about 70 cells parallel on ervery seriell so if one cell go bad it will not be a drama!
the other one is that every pcb bord is protected with 5 amp fuse!!
next month i will be complete with all connection and the we will se how it works?

TrustyFly said:
Yeah I am not an expert but I do not think I understand why they would not get out of balance. Let me try drawing my idea of what would happen:
Pack 1 ++++++++ 29.6v
Pack 2 ++++++++ 29.6v
Pack 3 ++++++++ 29.6v
Pack 4 ++++++++ 29.6v
Pack 5 ++++++++ 29.6v
Pack 6 ++++++++ 29.6v
Pack 7 ++++++++ 29.6v
Pack 8 ++++++++ 29.6v
They are all balanced and everything is good but what happens if a cell goes bad.
Pack 8 ++++++-+ 25.9v
This will balance them all out to 25.9v and in a safe way to the other packs. But when you charge to 4.2v per cell or 33.6 each cell in pack 8 will have 4.8v per cell.

Maybe I am not understanding completely the setup.
Click to expand...

hi
yes i have 10 packs!! 2 in series also 5 packs with max 58,8v but every pack is an 14s14p configuration! so 14 cells should be go bad if this scenario would happen!!
i build ebike packs for over 5 years so a little bit knowlede i have in building this packs!
that is not other as a powerwall with 14s70p configuration!!
 
love the pips & the way they are housed - can't say i'm a fan of the cell pcbs - but watching closely as i bet someone soon proves me wrong and makes me like the idea for real powerwalls
 
So my small powerwall ist firstly ready to go!
After a few test with the PCBs i had a bad feeling with it to use it for a big powerwall for my house!! So i changed the idea for new LifePo4 Cells made in germany!
They are big cells with each 45Ah!!
My configuration now is only 16S2P but with more money i will do it bigger?
First test with on cell were great! i take over 120A ( nearly 3C ) and voltage drop only 50mV!!


image_ajxdys.jpg


image_vnmpiv.jpg


image_swqihb.jpg


image_spmsyz.jpg


image_eotcyj.jpg
 
Dont forget bms ;) you need individual voltage monitoring for the protection ;) Good works !
 
thank you!
now i have 16 deligreen actice balancer and viktron bmv for over-under volt protection!
 
Looks nice and neat. Espacially the metal casing you've build everything in. How did you make or where did you buy the busbars where you connect the pis with the battery?
 
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