A DIY Power Wall ???

[Mike90250]

Fine wire is not a fuse, Better with a real fuse and holder (where do those bits of molten metal fall ?)

Matching used cells for Todays capacity is fine, What about in a month when they age some more ?

Used cells - where do they come from ? old battery packs? fleabay vendors? Are they all the SAME chemistry ? Used for 3 years, used for 6 years, nobody knows.

The final kicker - soldering the fine wire to the cell terminal. Guaranteed to ruin the seal and let the cell dry out. Factory packs are spot welded nickel wire

And yes, an outbuilding, nothing critical there to burn up.

[NEOH]

One of many DIY Power Walls being built ...

Is this "SAFE"? ...

http://diypowerwalls.com/t-Glubux-s-Powerwall

If it is not safe, then specifically WHY not?

Q1) He used a fine wire on each battery to individually "fuse" each and every battery - If sized correctly, is that enough? Or add real DC fuses?

Q2) He assembled with used batteries - Can that cause early failure? How?

Q3) It is installed in an separate, distant "out-building" - Why? Because it is a potential fire hazard?

Q4) Does the core temperature of each "parallel pack" need to be monitored?

Q5) Must each "parallel bank" be individually balanced?

Is there any way to make this SAFE?
If yes, then how exactly?