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ON7RU's 18650 Modular 48V - 8KWh powerwall (Belgium)
Thanks for reading, with this write up I share the adventure that started over 1 year ago. In that timefram I tested a lot of cells and aquired the skills by building 2 1KWH PWs.
Since one month my 48V - 8kwh is up and running and I'm very pleased with the results.
I've added some referral links, this support will help me to create extra content and YT videos.

I'm charging my single 18650s with the well known TP4056. During the process several charge boards were made.
At the moment I can charge +40 batteries at the time and check capacity from 10 cells at once.


Capacity check is done with this litlle wonder, it's very consistent:


Sorting & building
When I started collecting batteries I hesitated between a 24V or 48V config, but quickly found out that 48V was the route to go. So 14 packs of 80 cells were made. The positive side of each cell is fused with a 3A glass fuse.
The first 2 PW had soldered connections, now I treated myself with a spotwelder, the well known SUNKO 709A. Very pleased with the performance and results.
At the back I welded 4P nickelstrip and added a copper busbar. For the next "shelf" I will no longer use the nickelstrip.

Sorting batteries to 80P packs

While working on the pack, I convinced my better half to install the solar panels in the garden where they are facing south.
Besides welding and soldering, I also had to work on my bricklaying skills, but most credits go to my brother who works in construction.
A frame was built with the help of my father in law. Should withstand T3 storms.

The frame is made for 12 panels. To charge the batteries I use the well known PCM60X. 4 strings of 3 280W panels are connected via a DIY combinerbox to the charger.
More info on the combinerbox in this dedicated thread: LINK HERE

PCM60X infotainment.

The EASUN 5KVA inverter generates upto 4KW. For now, I internally limited to 3KW via software. The power goes through a breaker box with earth leakage protection.

Manually disconnects solar and batteries from inverter.

To bring the 220V inside the house, I had to trench 25m. Close to the garage there was a large PVC tube for my hamradio coax cables. Luckely there
was enough room left to add the 220V and some control cables.

Once indoor I connected the power to an ATS, automatich transfer switch. This device switches automatically between the grid and the powerwall.

So when the batteries go low, the inverter switches off and it takes about 3 seconds to connect to the grid.
Indoor I have seperate circuits to our waterbed, washing machine, and several wall outlets. Typical daily usage is 4Kwh. 

Found some nifty devices to measure the used energy. 
They allow me to switch of power and check the energy usage wherever I'm connected to the internet.

The app shows current, daily and montly usage and you and acts as a switch too.

Balancing you ask? Ofcourse! A small package but great performer. Works like a charm.
As I want to add another shelf in the near future I bought the 2A model

All balance leads are equally long.

Great results

And now back to work, there's enough room to add a couple of shelfs.

Comments and questions are welcome and appreciated.

Frank, ON7RU
chuckp, hbpowerwall, ajw22 like this post
Very tidy, but that hedge needs to go.
Very Cool.   

What stuck out for me is that like you, I use automatic transfer switch(s) ( ) so my off-grid solar system will automatically supply power when the inverter comes on and grid automatically takes over when the inverter goes off.     

APC UPSs are used to smooth power to computer/tv and other electronics that need constant power - so the twice daily switch of power does not disrupt anything.

Use Pro/Tran "Manual Transfer Switch" at the main panel ( ) to have ability to easily (flick of switch) adjust how load is presented to the PV system.

Using cheap meters to monitor key areas of consumption - but working on automation for this.    

My first batch of panels are on the south roof but am in the process of putting panels over some recently installed rain harvest tanks - built a frame work of 2" galvanized steel with 24" (wide) / 42" (deep) concrete pads per IronRidge online design tool.    Looks similar to yours... Smile
cdeforrest likes this post
A few weeks ago, I gave a presentation about my installation, happy to share the slides with the community

In Q1 2020 I will add another shelf with 1120 batteries, try to make a movie with more detailed info.

In case of questions, don't hesitate to ask.

In your "Battery - proces[s]", you re-charge and re-test the cells that fail at ">4.10V". I'm guessing that's to give cells that require a "waking up cycle" a second chance? How often do those cells pass on the 2nd try?
Modular PowerShelf using 3D printed packs.  60kWh and growing.
Hey ajw22,

Most of these cells have 4.06 to 4.09. I noticed some TP4056 cut off a bit to early, so that why I added this second chance loop.
They "loop" 1 time. If they fail again it's straight to the bin.

Have no exact figures, but I think that +70% of the cells that pass the second test end up in the "spare batch" with capacity between 1500 - 1850mah.
Suppose the internal resistance increased, the TP4056 cuts off all makes sense.
ajw22 likes this post
Doubled capacity of my powerwall to 15kwh usable energy.

2x (14s 80p) generated over 200kwh each month for the past 2 months.

Details available on my website.

Let's update the cell counter  :-)
OffGridInTheCity and Rekim like this post
The inverter you use is fake it is not Voltronic , did you know it ?
Anyway is there any particular problem especially for the firmware ?
(05-05-2020, 09:07 AM)Engineer34 Wrote: The inverter you use is fake it is not Voltronic , did you know it ?
Anyway is there any particular problem especially for the firmware ?

No I didn't knew that. I was told inverters from MPPsolar, easun and others are engineerd (and built?) by voltronic.
Inverter has 8 months and +820kwh on the counter, never missed a beat. So far I'm a happy camper.
Rekim likes this post
MPP %90 Voltronic they don’t go fake producers but Easun might. Anyway fake ones almost catch the Voltronic quality
with even cheaper price. Just Voltronic is advanced on software and innovations.

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