[masklinn]

According to https://www.sciencedirect.com/science/article/abs/pii/S03787... the batteries Tiamat produces are 18650 format, 3.7V, 0.61Ah. The latter more or less matches the specs of the product. This would mean the product might have a single 34g battery with a specific energy of 68Wh/kg, and 135Wh/L. So low end of nimh. Which sounds somewhat reasonable, 10 (and around 20Wh/L) I don’t think you’d bother even going forwards with.

Sadly I can’t find any teardown of the product, it’s all just press reprints.

There’s a split view PDF (in the documents section), it doesn’t seem to show the battery but does not show a huge amount of space for it.

[aredox]

I got the same 68 Wh/kg from this report: https://www.greencarcongress.com/2023/10/20231030-tiamat.htm...

[foobarian]

Low end of Nimh doesn't sound very great, but - what if you could get 18650 cells for (making up a small number) $0.50 each? I think I would end up with a box full and just swap them as I use them. Even better if they retain charge well.

[aredox]

It has other great advantages over NiMH: fast charging, no memory effect, no self-discharge

[tzs]

NiMH self-discharge is low enough to not matter for most applications. 5th generation Panasonic Eneloop is 90% after 1 year of storage, 80% after 3 years, 75% after 5 years, and 70% after 10 years.

[orangepurple]

NiMH doesn't have noticable memory effect. NiCd does.

[foobarian]

Absolutely! However my baseline are my Li-ion 18650 cells which have those advantages as well, in addition to larger capacity. But I think I would be willing to give up the capacity if the price was much lower.

[seec]

Yeah, considering the tradeoffs it has to be much cheaper to be worthwhile. I would say 5-7 euros per cell retail to be worth considering. Otherwise why bother ?

[scythe]

This paper describes Tiamat's battery as Na3V2(PO4)2F3:

https://chemistry-europe.onlinelibrary.wiley.com/doi/pdf/10....