I should do a write-up on battery pack failures, I've collected a small mountain of data on this, it might be useful to others.
Many thanks for the rear carrier information, this is something I will have to really deal with somehow, the frame gap on this bike is just too bloody small and I don't want to permanently alter the bike in case I want to sell it. I've done quite a bit of cycling with kids on the back so I'm used to having a lot of weight there (and one on the front too, total bike weight in excess of 130 Kg), but it's something that will have more effect the faster you go.
What's definitely out is an off-side pack or to have it split across the carrier bags, that's asking for trouble, both from a mechanical point of view and an electrical one (you'd be running quite a few wires between the two sides). At least a carrier one is going to be centered on the bike.
Cells are arriving tomorrow, for now I've decided on a 10x20 grid (so a few more cells ;) ), 21 x 41 cm plus some room in front to house the BMS. the box will be fairly low, about 90 mm altogether so that should help keep the COG low, the carrier is rather low on this bike so on the whole it might not be that bad. I'll be sure to be extra careful with wet roads and I categorically refuse to cycle when it's icy (I have a bunch of steel in one leg from a previous accident so falling again is really not an option).
At least my adapter works, so I won't need to butcher the bike wiring harness.
If you want to take this out-of-band: [email protected]
>I'm not quite sure what 'modern' means in this context but all of the batteries that I've seen so far (Samsung, LG, Sony) caution in their MSDS against deep discharge both from a functional risk as well as from a safety perspective and there are a number of pretty knowledgeable people online who are on the record with their reputations at stake cautioning against this
Basically by modern they mean higher capacity than the ones in the 2006 study that found dendrites at 0V - those were early 2000s era tech, shoddy 760mAh cells. They found that the higher the specific capacity, the higher the resistance to Cu becoming dissolved.
As far as constructor experience I do agree with you, it's preferable to avoid it. Though one factor is that people with extensive commercial experience will probably have had to work for very cheap, low capacity 1600mAh cells that are definitely more prone to this, and quite old arrays. I definitely recommend against it too, it just seems to me that it won't result in a fire anymore. I wouldn't take the risk though with a cell I know was discharged to 0 or beyond.