SolarPowerWall (Germany)

iDIYot

New member
Joined
Jul 12, 2020
Messages
4
hi,
long time passive reader, now its time to say hello...
working with electronics and computers since 1982, build my first offgrid solar 1986.

some pictures of my project, 1/2 finished:
400w 72cell solar
epever xtra4415
smartbms 6s + esp8266 webserver/mqtt for smarthome integration
480cells (same type, same source, 95%)

cheers
iDIYot


image_sezvui.jpg

image_ulkthk.jpg

image_wpaler.jpg

image_ssflxx.jpg

image_wwnhcv.jpg

image_yakfjm.jpg

image_olitdc.jpg



safety first, packs are spotwelded, single fused, fr4 covered, 1.5mm steel housing

bms dinrail holder & cell cleaner/grinder
https://www.thingiverse.com/idiyot/designs

cheers
iDIYot
 
Very nice looking, but be aware that this design is not suitable for high current usage... perhaps sustained max of 10A~20A(*1) 20A~30A. All thecurrent has to pass through the areas marked in red, which at the narrowest point probably has only about 3.15mm^2 cross section (guessing 7mm wide x 0.15mm thick x 3 bridges). A copper wire soldered along the orange line would help a lot.

(*1) Just looked up the electrical resistivity of nickel (4x that of copper) andsteel (8x ~ 40x that of copper).
https://en.wikipedia.org/wiki/Elect...stivity_and_conductivity_of_various_materials


image_hnxeyf.jpg
 
2 busbars per area 6mm each are prepared for soldering, test current was less than 10a...

thanks
iDIYot
 
Most interesting way of connecting the cells.
Hope that type of connection provides sufficient current.
 
6s folded (u-form)
load 80-120w (home server & cctv+ir)
current should not be an issue...

iDIYot
 
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