18650 Garden-Powerwall with 50KWh in Germany

[Stefanseiner]

Yesterday I tried to build a mounting system as HB uses. First idea: to find a manufacturer who can build this and uses the CAD files HB provides in his thread

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

time to connect both powerwalls together, but the voltages are not the same. no. 1 has 51,25V

and no. 2 has 47,76V
I would not recommend just connecting to wires together with hands because there will be a huge spark in the moment of contact

but in this case all is already wired together and I just have to activate the throughput via the bluetooth app of the bms. When you start them they automatically go into a safe mode and deactivate charging and discharging and you can change these settings manually.
Here you can see that round about 30 amps goe from pack 1 to pack 2, thats about 1.500 watts

akku 2 soaks the 30 amps up
30A are no problem, the bms are good for 60A current and 120A max, as well as the 60p akkupacks

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

 

[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.

 

[Stefanseiner]

ready connected and running

now there are 50 KWh of total capacity up and running

the next batterypacks with an estimated total of 20 KWh

I will try to complete this build within the next week

 

[Stefanseiner]

I went to the doctor because I felt ill.

Good news: ist's not the Covid-19 virus - but another kind of virus

The Doctor has no idea how to cure the symptoms maybe you do? Please help.

 

[OffGridInTheCity]

Looks like a 1s BMS might make things better for you - maybe put you to sleep if you get overloaded

 

[Alaa]

Great job

 

[Stefanseiner]

does anybody know a MPPT charge controller with battery voltage range 52 - 65V or floating voltage 65V?

I am getting my 16s100p system at the garage finished today and recognized that my JN-MPPT-Mini 30A charge controller is able to set the float voltage to a max of 100V (I set it to 65,0V) but it seems that the charge controller ignores this high setting because effective maximum charge voltage is 56,7V - which is shown at the display when running too.
So I have to find an MPPT with 65V charging voltage or reduce the battery system to a 14s which will cost me 2KWh of capacity

 

[Stefanseiner]

after some research I only found two charge controllers which will fit the 65V.
- MakeskyBlue v118 and v119 (maybe the clone from PowMr can do as well) -> round about 160USD for the 60A version
- EPever Tracer AN series -> round about 300USD for the 6415AN = 60A version

Last weekend I found on eBay a 6415AN as customer return with full warranty for 100USD and so I bought this (and just selled the two "old" charge controller for about 80USD each )

yesterday I installed the EPever. For this I had to do some modifications at the cables at the wall because the EPever is much bigger

now the batteries can for the first time be fully charged

to access all parameter of the EPever you'll need the additional MT50 Display (round about 18 USD).
And now the system is running in my preferred voltage range from 52,8V to 65V which is single cell voltage 3,30V to 4,05V

and I added a voltmeter with shunt to the system so I can see what's going on with the batteries without connecting to the bluetooth app first. It's at the exakt position where I look first when I leave my car when coming home.

Now the garage is ready and I can charge the car with the sun