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