Dubious about using the pattern batteries, mainly due to having experience with the 3750 cells they use.
In the past i have come across some of these type cells, namely ULTRAFIRE brand - fire in the name being the clue !
Seen them swell, glow and explode.
I have split many "knackered" batteries packs, removed the individual cells, gave them away to the lads in our sea fishing club (we use the fenix cree headlamps mainly) and these use the same individual cells as dyson packs.
In the last couple of years i have failed to find a bad 3750 cell in a dyson battery pack, so i suspect in my case the control pcb has some form of logical charge counter. (old panasonic toughbooks) cf27 model batteries have similar design and again with them all the cells were ok. On the battery casing there is a ps2 type connector leading to a populated pcb, so i suspect the battery pack counter can be reset ?
The dyson cells in the past were samsung 2200Mah or 2.2 amps at a nominal 3.75v - i discharged mine fully / safely in a housing cradle i purchased from china - then recharged 2 cells in a nitecore standalone charger with no issues on charge or discharge.
Very good quality cells actually, myself i use even better panasonic cells.
Worries me when i see shops with battery recycling boxes full, with the potential to short circuit / catch fire ?
Future quotes from myself to customers will be for a genuine battery now i think, as for the head i will give the option for a pattern or original, i will run the pattern stu and claire are sending me on my own v6.
Filters i will have a look at prices etc, but prob go for original as i dont like call backs...