[electric_skids]

Just found a 2nd hand 24V 5.3kWh 233Ah tesla battery module for aud$2200. 444 Panasonic 18650 cells.
Being used it obviously wouldn't still hold this much.

But the same capacity from these 18650 cells, LG M29 2.85 Ah, after adjusting for only using 80% of capacity would be
$250 + $450 shipping. For roughly 100cells.

Pretty big price difference. I know a diy battery would still need BMS, cooling and a box. Is there something I am missing?
Tesla brand name tax? Panasonic, Sony, LG and Samsung all make great cells.

 

[reiderM]

Just found a 2nd hand 24V 5.3kWh 233Ah tesla battery module for aud$2200. 444 Panasonic 18650 cells.
Being used it obviously wouldn't still hold this much.

But the same capacity from these 18650 cells, LG M29 2.85 Ah, after adjusting for only using 80% of capacity would be
$250 + $450 shipping. For roughly 100cells.

Pretty big price difference. I know a diy battery would still need BMS, cooling and a box. Is there something I am missing?
Tesla brand name tax? Panasonic, Sony, LG and Samsung all make great cells.

Your math here is waaaay off. You're only taking into account the Ah rating of the pack and cells. As I'm sure you know, watt hours = volts x amp hours. So you're comparing 285 Ah of 3.2v cells to 233 Ah in a 24v module. You would need more than 600 of those 18650 cells to match the capacity of the 444 cells in the Tesla module.

So the Tesla module comes out to be fairly comparable in price to the other option. Tesla cells are the best you can get, minimal degradation and great Ah capacity per cell.

Both batteries would still need a BMS.​

 

[electric_skids]

Thanks for correcting my stupid @reiderM. I also found these websites which helped me understand it more.

Battery pack calculator : Capacity, C-rating, ampere, charge and discharge run-time calculator of a battery or pack of batteries (energy storage)

EV design – battery calculation – x-engineer.org

Tutorial on how to calculate the main parameters of an electric vehicle (EV) battery pack (energy, capacity, volume and mass)

x-engineer.org

Yep your right, with prices being similar, that would easily make the 24v tesla module the obvious choice.

I'm gonna go spend more time learning and searching before I start a conversion.