100KWh DIY 18650 Powerwall in Germany

[curiouscarbon]

Hello Stefan! Thank you for documenting and sharing your project. You look so happy in the photos you take with the completed work ? well done!

It is interesting to see such resourcefulness and travel to achieve a large 18650 build. After seeing the title kWh and type of battery I just had to read!

Your engineering is very pleasant and again thank you for sharing! It helps me learn.

 

[curiouscarbon]

beautiful work, Stefan! ?

 

[Stefanseiner]

Yesterday I tried to build a mounting system as Pete from "HB powerwall" uses. First idea: to find a manufacturer who can build this with CAD lasercut.

but then I decided to build it for my own out of an old 2mm metal plate




first I cut a template which I can use for the plasma cutter


it's my first work with the playma cutter, so results ar far away from perfect...



...but much better then with a angle grinder




this will be the boddom part of the mounting plate


for the top part I build a second template

some work left for the angle grinder. Rounding the edges and grinding the metal slag


I will not use a single plate but four parts because I will build up a 16s100p system and therefor a single metal plate would be very huge


about 5 hours later


drilling some mounting holes


because I don't have a brake press I bend the brackets with a hammer


sits and fits


ready for painting


I am using metal protective paint in anthracite...


...with some "hammer blow effect" (don't know if this is the correct term in English)


state of yesterday evening, now the parts will have to dry and after christmas it will going on

 

[Stefanseiner]

in the meantime the mounting system is done and installed


time to build the packs.
It's a recycling of the "bad" cells between 1.500mAh and 1.900mAh


the good ones above 2.000mAh are sorted in 50mAh parts, this are only sorted in 100mAh ones. But I think that in the planned 100p packs they will level out


IR of every singel cell checked


this is the part of the building process I like the most


very satisfying to complete the packs with cells which got so much time to prepare


the side you will see with red Sanyos


put the top cover on...


sits and fits


very nice to fill the mounting system with akkupacks


just slide in and that's it




On the right side there is a MPPT charge controller (JN-MPPT-Mini 30A) and a grid inverter with limiter which is connected directly to the wallbox so the battery will not feed into the house but only into the electric car I will get within the next few days. Besides the inverter there is the surge protection box (AC and DC), and then the wallbox.






next step are the busbars and fuses





The busbars are made of 3x 2.5mm² copper wire and a SC16-6 (16mm²) ringterminal at the ends.
The load on the packs will be limited to 20A


terminals at opposite ends because of the length of the 100p packs


I am using fuse wire (0.2mm / 5amps) at both side. I know one side would be enough but for me it's the easiest and fastest way to connect cells and busbar to use this fusewire

 

[Stefanseiner]

I solder the fuse wires to the cells with a cheap solder-station from eBay. For me 370°C on the positive side and 390°C on the negative side seems to be perfect. At low temperatures about zero degrees at my garage where I am working you can add 5°C for soldering better


to solder the fusewire to the busbars I am using a 150W iron from Ersa, the 150S. I tried two cheap chinese irons but the tipp will melt faster than a candle and hinders me all the way in my working progress.


as solder wire I am using one with Sn60% Pb40% with fluxcore. Works very well without any cold soldering points. I need not more then 1 second per solder point at the cells and 2 seconds at the busbars.


here is a horrible boring video but without timelaps you can have a look at the working speed

after finishing the packs I charge them up to 4,05V...


...and test the real capacity between 4.05V and 3,30V with the modified DL24 electronic load at a discharge current of 15A.
The all have about 500Wh


to complete the installation I build some little BMS-holder


because I build up two powerwalls in parallel I am using two BMS. This is the small one with 60A/120A max and integrated active balancer with 0,6A balancing current.


the bigger, black one on the left can handle 150A/300A with 2A balancing current


some connector-plates


now it is nearly done. The two banks on the left are one system with 8KWh and the one on the right is another 16s50p system with...


...I build as a devided pack-design to get the same size as the first powerwall






then, the last days in the old year I got my new car I am waiting for several month. It's an
Aiways U5 full electric car with 150KW engine and 63KWh battery (good for a range of 400KM)






with a total of 8 cameras and all electronic assistance systems you can get this time including autonomous driving


Because I do shift work I can't always charge directly at my photovoltaic and so with the powerwall this should save a lot of money.
btw: electric prices in Germany are the highest in the whole world with 0,39USD per KWh

 

[Stefanseiner]

after this side project at the garage I can go on with my "main" project

the plan:
-> the smaller powerwall at the Infinisolar E 5.5KW will move into the left locker (2x 14s60p with a total of 11KWh in summary)
-> the powerwall with the bigger 120p packs will move to the locker on the right (2x 14s120p with 27KWh)

both locker only have one compartement so I have to add some more shelfs
because it's my first time of welding thin 2mm metal I have to practice a little at some remnants

after a while I found the perfect settings, but it's a very slow scope
btw: my first welding tries in general are from last spring as I repaired an old traktor with some 6mm and 10mm steel...

to get a good contact for welding I grind two stripes in the inner locker

this are the shelfs, 2mm steel too

some markings

but stop, befor welding I should put the rockwool to the back of the locker first, would be easier then after the shelfs are insered
it's rockwool in 40mm with WLG032 and fireproof higher than 1.000°C

no I can weld the shelfs

some welding magnets as little helper

nevertheless there is not much space for working it works well - but I don't think I will get a design award for my welding skills ?

redy done

then the locker have to move from the garage, around the house, through the granary into the old pigsty where the inverter is installed

last thing to do for the first day: painting
to be honest - I don't like the color because it's very shiny. But I've done a mistake with the order, I wanted black metal protection paint with some hammer blow effect - and this is without. But in the end it's no big thing, the locker stands in the pigsy and important is that it's some metal protection painting.

the next day I will continue with the fireproof insulation

 

[Stefanseiner]

all walls will be insulated with the Isover UKF 40mm WLG032 rockwool

for testing the space use a 60p pack of heaters

all metal surfaces will be covered with fermacel 10mm plates

Fermacell is fireproof over 1.000°C too

time for the powerwall to move from the box to the locker

this are 4,3KWh in 840 cells

disasseble and prepare the packs

between each pack I put a Fermacel spacer

simply cut with the cutter knife and bend over a edge

there is not much space in the locker - the spacer are too high so I have to cut them down, but 1 or 2 cm are too less for the cutter knife, so I will use the band saw. I guess the saw band will be dull very fast but...

...that's the original OEM band and it is not very good and I wanted to exchange it anyway

very tight but space enough for 6 packs

on this picture you can't see it, but actual I hace a fermacell plate on the top of all akkupack rows to prevent a fire can jump from one pack to a neighbour

16mm² cable for the packs

I am using M6 screws to attach the packs directly

the second powerwall is at the garden shed

on the right side it's a little powerwall I build up for my mother with 3,3KWh, it's just connected for testing. Left is the bigger one with 6,8 KWh

 

[Stefanseiner]

the boxes are with fire proof insulation too and it helps to get them a little warmer in winter too (16,3°C and 48,1V)

18,9°C at the bigger one

the other 14s60p system will move into the locker too

disassambling

with the second powerwall I go from the bottom to the top so the both positive poles will meet at the middle of the locker

looks bigger in reality

all packs are numbered. The voltage meters are dead because of the low voltage below 3,0V

here is the middle

ready attached

a little additional workaround at the inverter. First I did not think about the system could be crowing and so I only used one pair of cables with 16mm² for one powerwall.

Now I add another pair of 16mm²

two double-circuit breakers for DC with 63A each (in fact 4x 63A so positive and negatice wire has singel protection)

cable entries

im oberen Fach (orig. Zwischenboden) ist nun genug Platz für BMS, Kabel, Schalter etc.pp.

at the end both powerwalls are connected in parallel at the inverter, but they get their own bms

for mounting the bms I build a little basis

 

[Stefanseiner]

with some hinges to use the space into the locker best

some holder for the bms

by the way this are "JKBMS" with integrated active balancer and bluetooth app

I glue some nuts at the bottom for better ventilation

on top of the middle plate on the right there is the negative for both bms which goes to the inverter, on the left will be the positive
in front there are the both separate negatives which goes to the powerwalls

all parts from the "old" powerwall box will be reused

the two cells are needed to start up the bms

the little pcb is a DC-DC converter

the JKBMS have a data connection, and with this external dongle they provide a Canbus / RS485 signal

the RS485-signal oes via "Modbus-over-Ethernet-Adapter" into the house network so lateron I can monitor all the values from different BMS over one grafic interface

the DC-DC converter with 12V is for a voltmeter / ampmeter / thermometer I will add later on the outside of the locker so I can check the status very quick and without some monitoring app
and another DC-DC-converter with 5V for the Modbus-to-Ethernet Adapter

therefor I am using hinges, now there is a little more space in the middle

in the meantime I changed the bms to the same model, the JKBMS BD6A17S-6P with 0,6A balancing current, 13S to 17S, 60A / 120A max. = round about 60 USD
actually I wanted to use the bigger BMS with 150A/300A and 2A balancing current for the bigger 6,8KW powerwall, but then I noticed that this model (the old revision) has no data connection

and so I am using identical models with data connection

positive wire for both packs

 

[Stefanseiner]

minus from each bms to a separate powerwall

before I connect the balancer wires I prepare the other locker compartments

the three compartments will be mostly identically and all will need 5V

this is the part for the middle compartment. Difference here: two little network switches to connect 6 bms over their modbus adapter to the network

at the end there will be just one networl cable leaving the locker

the switches are working with usb, but I connected them to the 5V DC-DC-converter too

fits

just drilling some more extra holes to be able to connect the three compartments

this is a real fiddling - balancer cables

I solder crocodile clamps on each balancing wire so I can take a akkupack easy out of the locker for service
"3 / 4" means -> goes between akkupack no. 3 and no. 4

I hate tangled cord...

... and I love zip ties

 

[Stefanseiner]

after an hour at the charger the voltmeters are back in life

then the balancer connections of the lower powerwall

just more fiddling because all wires have to be extended

that's it so far.

I hope I can finish my project in February because I have lots of plans and projects I want to do in my garden this year and therefor I will not have time left for the 18650 project

 

[upnorthandpersonal]

Guten Morgen, und willkommen im Forum!

I once considered 18650 cells, and I have used them in smaller projects, but building 100kWh with 18650 would drive me mad

Good to see another JK BMS user - there are a few others on here (myself included) that use them as well.

Nice work!

 

[MasnPip]

I admire your work! Thank you for sharing! Please give us an update as to how everything performs - I would love to follow your progress with your farm.

 

[Hedges]

...with some "hammer blow effect" (don't know if this is the correct term in English)

"Peening"

btw: electric prices in Germany are the highest in the whole world with 0,39USD per KWh

San Jose, California, USA is out of this world.
Peak time (4:00 PM to 9:00 PM) it's $0.50 USD per kWh.

 

[Stefanseiner]

"Peening"

Thanks for the word
And wow - 50 USD / kWh are very hard and such prizes will prevent electro-mobility

Please give us an update as to how everything performs

yes I will, of course This is my first summer with LiIon powerwall so I am exited for my own how it will perform.

Guten Morgen, und willkommen im Forum!

I once considered 18650 cells, and I have used them in smaller projects, but building 100kWh with 18650 would drive me mad

Good to see another JK BMS user - there are a few others on here (myself included) that use them as well.

Nice work!

Thanks
And yes, it's tons of work to do this project and if I knew before hoch much - I definitely did not started ;-) But now that I am in the middle of this work and see and feel first results - it's like an obsession and I have to go on and on

And I like the Jikong BMS, they offer pretty much functionality compared to the prize and at this moment I have 7 of this (different models) running.

But unfortunately I have to say, that two of the small active balancer BMS JK-BD6A20S-10P are dead after a few weeks of usage in my 16s powerwall at the garage


both seem to have "lost" some batteries. The first BMS lost batteries no. 01, 02 and 09


I first checked the cable connections. I checked it twice and three or four times but could not find any problem.
So I replaced the whole cables but the problem staied.

At the end I replaced the bms with the same, new type of BMS


but after few weeks it losts some batteries too, this time no. 01 and 16


Again I checked all cables but could not find any problem so defnitely a failure of the BMS.

Maybe a bad charge of production. In total I am using seven of this exact identical BMS and the others run just fine, some of them non-stop since one year.

I contacted the seller on Aliexpress, D.YU.K.B / Dykbhuang Store (two names, same seller) and he agreed to refund the two defective BMS after sending it back and so I did so


But because he did not confirmed the arrival of the package in time, the dispute was closed autimatically and there is no refund.
I wrote several times via contact form and the seller agreed one more time to refund the defective devices but now, six weeks later there are still just some delaying tactics and no refund.

I guess it's my fault because I thought the chinese seller has some honor and will hold his word, but it seems this is not true.

So all I can do now is warn you about this seller.
I guess next time I need a smart BMS or active balancer I will order at ICGOGOGO again. It's three or four bucks more expensive, but service is definitely better.

 

[Stefanseiner]

before the next step starts here a video of the actual project status (you may activate subtitels)

disassebling the last few ebike battery packs

their are all chinese OEM cells from FST, BAK or noname

disassebling of most of them is horrible because their are glued together

50% of the cell covers are hardly damaged so I have to renew them later

altough it's a good deal because most of the cells are quiet new ones with 2.700mAh with an BMS failure and full capacity

about 300 cells are "naked"

this is the first time I try some magnets to fix the batteries

thanks at Pete for this tip

works a lot better then with washers I used befor the magnets

todo: capacity testing

while testing the cells in the background I start to prepare the second locker for the second powerwall

I bought this for 25 EUR / 30 USD from an fitness studio

like the other locker too I will use fireproof rockwool insulation at all outside walls

 

[Stefanseiner]

40mm / WLG 0,32 / fire proof 1.000°C and above

preparing for welding

the shelfs are 300 x 300mm

after 2,5 hours of welding and grinding it's done. One compartment for one 14s-system.
I have two systems reday-build, so place left for two others if the capacity will not be enough

but at this point I have to wait for better weather to geht the locker down the muddy way to the garden shed

when the locker is at it's place I will begin to build in the components

 

[Stefanseiner]

despite it's -8°C work goes on.
Sanding the locker for new painting

some holes for the 35mm² copper wires

black metal protection paint

while the paint is drying I prepare the inner parts

10mm fermacel plates

in the meantime the saw band is very dull

finished. This are all parts for the shelf bottoms, walls, covers and for separators between the battery packs.
together round about 50KG

so the inlays are ready but the paint is still wet, so I process some more cells.

these cell holders are already stucked together and numbered

when finished this will be another
2x 14s60p for the first locker (photovoltaic on the wood storage)
1x 14s120p for the second locker (photovoltaic on the garden shed

3.360 batteries needed

some of them are really good ones

ready - go

I try to build the visable sides in green

the mixed batteries are for the inner space

 

[Stefanseiner]

for those who lost overview what's going on in capacity:

• actual there are 50KWh read to use
• 11 KWh in the old pigsty at the Infinisolar E 5.5KW with 2,8KWp on the wood storage
• 27 KWh for the garden shed at the MPP Solar MPI 10k with 9,3KWp on the roof of garden shed. The battery packs are not connected in the locker but already build
• 12 KWh at the garage to supply the charger of the electric car. No photovoltaic at this time, will follow in march / april, planned are 2,8KWp

until end of this month I will add:

• 2x 5KWh to the pigsty
• 1x 10 KWh to the garden shed
• in sum 70 KWh which will go for this summer seasson

this are the smaller 60p packs

on the right the bigger 120p packs

add the top cover

ready for soldering

the the paint of the locker is dry and the way from the house down to the garden shed too so time to move the locker.
But first I need some more space where the barbecue-firewood is stored

I got some help to move the big locker

I did not believed in it but we made it without accidents

new place for the locker

 

[Stefanseiner]

then carrying all the parts to the locker

equipping the shelfs and walls with the prepared fermacel plates

next step: carrying the battery packs. Six at the same time = 30 KG and 6 KWh

bank no. 1 is already moved into the locker

next 14 packs will follow

this are two banks, each consists of 14x 120p and 13,5KWh

because I made the busbars with two ring terminals I can't mount two packs together directly so I will try a thing

this is a copper pipe with 6,3mm inner diameter. Just fitting for the M6 screw to improve the conductivity and to fill the gap between two packs

cutting the pipe in 20mm pieces

deburring with the round file

this is how it looks now

this is the status from the last weekend

next week I will add the wires, bms and so on.