100KWh DIY 18650 Powerwall in Germany

[Stefanseiner]

sorry, but the point of view of the picture above is not very good,

but at the following picture below you can see the gap between roof and modules better. It's bigger than the roof overhang and shadow comes only when sun turns over to the west side. The balcony is exact east sided

 

[Hedges]

Oh, I had thought it was facing South so depending on your latitude, some seasons it might clip all day long.

I would like a panel to have clear view of the sun with at least +/-45 degree angle, a 90 degree field of view or 6 hours centered on optimum angle. Daylight might last 12 hours, but most power production will be during the period when panel faces sun, drops off quickly at large angle (except during overcast.)

As located, when sun is directly overhead at Noon it isn't shaded, but shadow falls on it shortly after. Panels likely have three diode-bypassed sections of cells; does the shadow cover only one section so the other two can keep producing power (assuming suitable voltage and MPPT charger), or does the shadow take out all three sections?

More tilt of the panel would increases the numbers of hours it gets unshaded sun after the point when it is aimed straight at the sun. But it would reduce the number of hours from sunrise to when straight at sun. There would be some angle that maximized power captured, at least for a particular day of the year.

My guess is that a tilt so panel lined up with roof would be pretty good. Sun would be several hours past directly at panel before the upper roofline cast a shadow on it.

 

[Stefanseiner]

my MPP SOlar MPI 10k seems to be broken
Maybe someone can help? -> MPP Solar / Infinisolar MPI 10k hybrid inverter died - fuse goes off when synchronizing with grid

 

[dralthi]

after the capacity-tests I checked the inner resistance with the well known Vapcell YR1030. But it's annoying to chek them laying on the table, rolling around so I builded a little helper-thing




now I can handle 150 cells








Timelaps video

I test them one by one and the bad ones (70mOhm or more) are pushed out a little bit, so when finished all cells I can sort them out for trash or other purposes




of course I had some cells which need a new heatshrink




purple is not my favorite colour, but I killed the complete stack of green shrinks within one unfocused moment while pan the heatgun :dodgy:




finally!! it's time to start the test-build




I am using the not-so-good laptop cells with round about 2.300mAh.
Laptop cells? In German internet forum you mostly can read about builds with laptop cells and how easy this is to disasseble, while eBike-akkupacks aren't easy to open and process, so I've given them a try and collected some laptop batteries from recycling companies.

to be continued

Incredible amounts of work! Kudos.

I would just buy a used EV pack lol

 

[Stefanseiner]

me too after knowing hoch much this work is :-D

Oh wait, just building some more powerwalls with another 7.200 cells right now. I guess I am unteachable...

 

[byteharmony]

me too after knowing hoch much this work is :-D

Oh wait, just building some more powerwalls with another 7.200 cells right now. I guess I am unteachable...

I am considering a plan for about 1500 18650 cells for a Sol Ark 48V DIY powerwall phase 1. For Phase 2 I'm hoping to electrify a lawn tractor and add it's capacity when it's not mowing.

Phase 1:
I'm planning to use JK BMS and building packs of modular cells:
14s10p. Then using fuses to connect them in parallel to make:
14s120p

I was concerned if a cell went bad, could cause a significant problem. I see in this project fuse wire is being used for every cell. That certainly isn't being done in many power tools and toys. I wasn't thinking of doing that for my project but perhaps, for safety I should???

I'm building some small tests right now for APC ups systems to get more experience as I learn. Your project is amazing, thanks for all your work and documentation!


Brian

 

[donmarkon]

@Stefanseiner Amazing work!
Can you pm me where I can get cheap used cells in Germany? (packs like yours) I'm building 10kw power wall so it would help!

 

[banne]

sorry, but the point of view of the picture above is not very good,

but at the following picture below you can see the gap between roof and modules better. It's bigger than the roof overhang and shadow comes only when sun turns over to the west side. The balcony is exact east sided

This can't be serious right? Over 50cm outside of the roof?

Read the rest of the story, I admire the work and effort but man, what risk one can take to save some money on buying LFP cells instead. Really curious what your fire insurance thinks about there powerwalls

 

[k490]

That is taking DIY to the max. Hope all is well I see it's been a year since you updated the thread.