Rechargable Li-Ion inserts for 8 cell packs?

I got to thinking the other day, why not replace the tray and 8 AA cells in the ubiquitous HV external battery packs with a rechargeable Lithium Ion battery pack?

My first thought was to find AA sized Li-Ion cells and just put them into the tray.
That appears unrealistic because the AA Li-Ion cells output more than twice the voltage.

Wonder if anyone has fiddled around with rewiring a Pixel pack so rather than two circuits there would be 4, two in parallel to the contacts for each existing circuit.

Yingnou and Canon have single circuit so it might be easier to rewire a tray with appropriate number of cells.

I've also notice there are a few 1.5V AA Li-Ion cells, has anyone tried these?

dmward wrote in post #16372987
I got to thinking the other day, why not replace the tray and 8 AA cells in the ubiquitous HV external battery packs with a rechargeable Lithium Ion battery pack?

My first thought was to find AA sized Li-Ion cells and just put them into the tray.
That appears unrealistic because the AA Li-Ion cells output more than twice the voltage.

Wonder if anyone has fiddled around with rewiring a Pixel pack so rather than two circuits there would be 4, two in parallel to the contacts for each existing circuit.

Yongnou and Canon have single circuit so it might be easier to rewire a tray with appropriate number of cells.

I've also noticed there are a few 1.5V AA Li-Ion cells, has anyone tried these?

David: I had much the same thought-train when I first came across Li-Ion cells - along the lines of "Ooh, goody - now what can I do with these". Then I started to seriously doubt the wisdom of manufacturing a 3.7v cell exactly the same size as an ordinary 1.5v AA - there's serious scope there for someone to not read the labelling (or not understand it), pop one or more of these into a normal circuit and create a problem. Hopefully, this would just be the (expensive) 'bang' and a blown circuit but there's always the chance of a fire.

Yes, no doubt a Pixel TD-3xx could be rewired. Likewise the Canon CP-E4 or Yongnuo but to what advantage? Do you remember the NiCd cartridges for the Metz 45 series? 6 straight 1.2v NiCd in series to give 7.2v. Then there was also the AA cartridge for 6 in-series 1.5v - this cartridge had to have a little extra 'twiddle' built-in to drop the voltage down to the 7.2v which those flash units demanded. We'd have to do the same to our little HV packs. Then they wouldn't be usable with ordinary AAs. Plus the probable need (not investigated) for yet another charger because of the voltage difference in the cells.

An interesting intellectual exercise but one I abandoned as not offering me any great advantages but with a potential disadvantage in versatility. Then I got my first Godox PB960 (Cheetah L4500) and now my Pixel packs are seriously underworked anyway.

1.5v AA Li-ion? Nah, never bothered as the number of non-rechargeables I use is tiny anyway. The only place I can think I use them is in the keypads of my safes; not exactly the highest drain application! Or have you found some rechargeable Li-ion cells?

I did find some rechargeable 1.5v Lithium Ion AA cells. They were all being shipped from China, and it appeared they were from the manufacturer with high quantity requirements.

Li-Ion do require different chargers. That's why it would require rebuilding the trays. One reason for thinking about this is that I have some extra trays, left over from packs that had circuit failures. (Early version TD-381s)