I got a NEW Powerwall then proceeded tare it down!

[hbpowerwall]

It doesn't often happen....

Someone: posts on Facebook - Who wants a Powerwall?
Pete: F$%^&*(!uck YEH, how much?
Someone: Free.....
Pete: what the F$%^&*(!uck

*insert noise of tire squeal & an aroma of urine from the shear excitement ... and two hours later

There is also a youtube video - that'll be released soon unless your a Patreon and in that case enjoy!



Install Manual - https://www.solahart.com.au/media/2...ns-solahartbatterysystems120022reva_small.pdf
Powerwall for sale - https://ebay.us/DO1HwD

 

[floydR]

How many kwh is Powerwall? I think there were at least three sizes of residential Tesla Powerwalls not sure what the latest size is

Later floyd

 

[hbpowerwall]

How many kwh is Powerwall?

Later floyd

From memory, it is 5.2 useable? This one unfortunately is a big fat ZERO!

 

[Sigmacom]

Was this the actual unit from that ebay listing you have linked above? Or a different one?

 

[AI LIFE]

Can you try to rebuild it with recycled cells it'll be awesome even if u don't have use to it it still looks cool

 

[Dietmar Rheeder-Kleist]

Pete, I watched your video on this Tesla power wall. I am however confused about why you only attempted to charge the entire 28V to only 1.5V at 0.5A.
I get that you wanted to see if it holds a charge, but you didn't apply this methodology even when you revived single 18650s? Also, 18650's have the low voltage of like 2V, so surely you should at least push the voltage to something that at least gets your BMS to recognise the different cells in the pack.
I mean I could be wrong, but when I worked through my 15000 odd 18650's that I recycled, there definitely was a "charge hump" that you had to get over to get the cells to revive them.
Anyway if I could make a special request: If its 28V, then its 7S. So 2.2v x 7 = 14.4volts minimum... also 500ma at least per series, so 7x 500ma = 3.5A at least.

So perhaps 14V at 3.5A for a few hours?

 

[OffGridInTheCity]

Pete, I watched your video on this Tesla power wall. I am however confused about why you only attempted to charge the entire 28V to only 1.5V at 0.5A.
I get that you wanted to see if it holds a charge, but you didn't apply this methodology even when you revived single 18650s? Also, 18650's have the low voltage of like 2V, so surely you should at least push the voltage to something that at least gets your BMS to recognise the different cells in the pack.
I mean I could be wrong, but when I worked through my 15000 odd 18650's that I recycled, there definitely was a "charge hump" that you had to get over to get the cells to revive them.
Anyway if I could make a special request: If its 28V, then its 7S. So 2.2v x 7 = 14.4volts minimum... also 500ma at least per series, so 7x 500ma = 3.5A at least.

So perhaps 14V at 3.5A for a few hours?

I was thinking the same thing. I get the 'gentle charge' part but not the the low level voltage. The 0v cells I've worked seem to do better once they get up to 2.7v or so. Then the issue ... do they get hot as the do regular 1a/cell charging and do they get hot at 4.2v as the bad ones try to self-discharge.

On the other hand, I do get that you're dealing with entire packs - not individual cells - and that even if the pack seems to charge up the worry is that individual cells within the pack are heaters / will form dendrites? And so unless one can test each individual cell - its bound to be risky to try to use the overall pack?

Which then begs the question - can the pack be disassembled (with reasonable effort) to individual cells? which could then be tested for good ones? I don't think I've ever seen a tesla battery taken apart for its individual cells...

 

[ajw22]

I for one have no issue at all with the procedure or the conclusion. He pushed 20Ah in, and it all "disappeared" completely within [inaudible]hours. From my limited experience, cells with any hope of recovery will level off at some non-zero voltage. The obvious explanation is that some/most/all cells have developed dendrites that are causing partial internal short-circuits.

Now, there is an (IMHO stupefyingly dangerous) idea that applying a high voltage/current to such cells can overheat and melt away the dendrite...

 

[Korishan]

I for one have no issue at all with the procedure or the conclusion. He pushed 20Ah in, and it all "disappeared" completely within [inaudible]hours. From my limited experience, cells with any hope of recovery will level off at some non-zero voltage. The obvious explanation is that some/most/all cells have developed dendrites that are causing partial internal short-circuits.

Now, there is an (IMHO stupefyingly dangerous) idea that applying a high voltage/current to such cells can overheat and melt away the dendrite...

With the size of the pack, if he had 5 self-dischargers, that might be enough to keep the pack from raising in voltage (just tossing numbers atm). So if he can overcome the self-dischargers drain and push the pack hard enough, those SD cells should show up on thermal. Disconnect them as they show up and see if the voltage raises and starts to stabilize.
Obviously this is done with great attention, outside in the yard or inside the container (if it's empty), and lots of camera angles (ya know, just in case, we wanna see the fireworks )