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I can't see how this works at scale personally. You'd at minimum need standards in cell construction so that you can plug them into some kind of rack. Battery p

I can't see how this works at scale personally. You'd at minimum need standards in cell construction so that you can plug them into some kind of rack. Battery packs as standard come in too many different formats, voltages and cell chemistries etc.

trainsarebetter 2y ago
Not really. Most pack are 96s Chemistry wise the only real major difference for charge profiles is lfp vs standard li-ion. Pretty much every pack spits cell data out over can, and contains hv contactors. Projects like https://github.com/dalathegreat/Battery-Emulator https://github.com/dalathegreat/Battery-Emulator Standardize different pack coms for HV solar inverters. The big hurdle here is insurance. It’s a regulatory nightmare, nobody wants to spend the money to provide the data that these packs are safe for grid tie. Even though they have the data for vehicle safety…
- VBprogrammer 2y ago
  Taking the Hyundai Ionic 5 as an example you have 3 capacities 58.2kwh, 72.6kwh and 77.4kwh with 114s2p, 180s2p, 192s2p. These have nominal voltages of 523v, 653v and 697v respectively. Even for the same car it's not trivial to use these all in the same system. It might even make most sense to couple them on the AC side but that would mean a lot of small expensive inverters.
  - pjc50 2y ago
    I'd assume the plan is not "use pack as is" but to split it into constituent 18650 cells and build a mega-pack. I'm not sure how reliable that would be..
    - VBprogrammer 2y ago
      Yeah, even that is tricky. Every different manufacturer has different packaging for the cells. The Nissan Leaf for example uses a pouch style cell rather than 18650 cells. Even if you stick to say Tesla batteries you have to undo the wire bonding and probably spot weld each battery back together, then balance and charge the pack ensuring you don't have any duff cells. It's a lot of work for reclaiming batteries on an industrial scale.
  - trainsarebetter 2y ago
    Hmm do you have any reference material stating they are in fact different series groups? that’s a odd way to do it, generally you just add more cells in each parallel group Regardless most hv solar inverters are 600v or 800v so all those packs would work fine

trainsarebetter 2y ago

Not really. Most pack are 96s Chemistry wise the only real major difference for charge profiles is lfp vs standard li-ion. Pretty much every pack spits cell data out over can, and contains hv contactors. Projects like https://github.com/dalathegreat/Battery-Emulator https://github.com/dalathegreat/Battery-Emulator Standardize different pack coms for HV solar inverters. The big hurdle here is insurance. It’s a regulatory nightmare, nobody wants to spend the money to provide the data that these packs are safe for grid tie. Even though they have the data for vehicle safety…

VBprogrammer 2y ago
Taking the Hyundai Ionic 5 as an example you have 3 capacities 58.2kwh, 72.6kwh and 77.4kwh with 114s2p, 180s2p, 192s2p. These have nominal voltages of 523v, 653v and 697v respectively. Even for the same car it's not trivial to use these all in the same system. It might even make most sense to couple them on the AC side but that would mean a lot of small expensive inverters.
- pjc50 2y ago
  I'd assume the plan is not "use pack as is" but to split it into constituent 18650 cells and build a mega-pack. I'm not sure how reliable that would be..
  - VBprogrammer 2y ago
    Yeah, even that is tricky. Every different manufacturer has different packaging for the cells. The Nissan Leaf for example uses a pouch style cell rather than 18650 cells. Even if you stick to say Tesla batteries you have to undo the wire bonding and probably spot weld each battery back together, then balance and charge the pack ensuring you don't have any duff cells. It's a lot of work for reclaiming batteries on an industrial scale.
- trainsarebetter 2y ago
  Hmm do you have any reference material stating they are in fact different series groups? that’s a odd way to do it, generally you just add more cells in each parallel group Regardless most hv solar inverters are 600v or 800v so all those packs would work fine