BYD packs — one year on — survey

[madsci1016]

Do all cells in the bank reach that voltage?
I would be really surprised to see that much degradation so quickly unless they were crap cells to begin with or they were used in extreme hot temps.

Yes, and usually a good amount of balancing energy is dissipated on a few cells.

Not sure you know the history of these, they were sold in late 2019/2020 already significantly degraded. 4Kwhr instead of 5.4ish they should be. They were retired from solar farms and had been built for extreme power in and out, easily 2-4C. But at the time for 4kwr they were a very attractive proposition in a time of expensive cells, china risk and group buys that ended up being scams. Now a days no one would buy something like this.

So these "Where are they now" tracking threads are those of us OGs that took the calculated risk and where we are sitting. They are a good example (education really) that degraded cells can't be helped, even with easy life they will continue to degrade. Also something we weren't really sure of at the time 5 years ago.

 

[42OhmsPA]

Yes, and usually a good amount of balancing energy is dissipated on a few cells.

Not sure you know the history of these, they were sold in late 2019/2020 already significantly degraded. 4Kwhr instead of 5.4ish they should be. They were retired from solar farms and had been built for extreme power in and out, easily 2-4C. But at the time for 4kwr they were a very attractive proposition in a time of expensive cells, china risk and group buys that ended up being scams. Now a days no one would buy something like this.

So these "Where are they now" tracking threads are those of us OGs that took the calculated risk and where we are sitting. They are a good example (education really) that degraded cells can't be helped, even with easy life they will continue to degrade. Also something we weren't really sure of at the time 5 years ago.

With the background that makes a lot more sense and would agree, unfortunately, there could be that much degradation.
I remember reading one or two of those group buy threads back when I was just a lurker.

Are you able to check IR on the cells?

Fortunately there are lots of "new" offerings out there at great prices.

 

[Quattrohead]

If you like the BMS and the case it sounds like these could be worth putting new cells in, might be able to do it for $750.

 

[madsci1016]

Fortunately there are lots of "new" offerings out there at great prices.

Yeah, debating on getting some EVE sells before tax credits end and tariffs begin, and putting these on marketplace priced to sell.

 

[iamrich]

Mine are still in use. I have no idea what the capacity is on either of them, but they power all my garage lighting and lawn tool battery charging, as well as a couple of exterior bulbs. My 250w Trina panels of degraded quite a bit, but still manage to top off the batteries every day. I charge to 27.4v daily, and once the sun goes away, they drop to 26.7v pretty quickly. Usually by morning, they are down to 26.3v.