[BeamerNub]

I'll try and keep this as short as possible, but there's obviously a lot of stuff I need to put in. I was driving to work yesterday, pulled onto a car park where I lift share from and then I accidentally stalled (or the car stalled, whichever you want to call it). Car started up but felt very rough, and very underpowered. Couldn't really get over about 60mph in 6th and it sounded quite loud as well. Unfortunately, my cheap little bluetooth OBD2 Scanner which is normally my goto wasn't working.... so I turned back, parked the car up and we took my mates car to work.

I got back to the car last night and it wouldn't start. The battery didn't seem to have much go in it and although it turned the starter, it wasn't happy. Eventually, the battery stopped altogether and by the time the car was recovered home, there wasn't enough juice to power the window wipers..... or the car was turning off the submodules to do so.

Towed the car home, scanned it:

CURRENT FAULT
P0366 - Powertrain - Camshaft Position Sensor "B" Circuit Ranger/Performance (Bank 1)
PENDING FAULT
P100F - Powertrain
P1030 - Powertrain
P110D - Powertrain
P1631 - Powertrain
P1637 - Powertrain
P2103 - Powertrain - Throttle Actuator Control Motor Circuit High

Cleared these codes, and tried to jump start it off another vehicle, again no start. Scanned again

PENDING FAULT
P0339 - Powertrain - Crankshaft Position Sensor A Circuit Intermittent

It was absolutely torrential rain by this point, so I put it on the smart charger, waited till this morning, cleared it, cranked it, no start, scanned it again:

PENDING FAULT
P0122 - Powertrain - Throttle/Pedal Position Sensor/Switch A Circuit Low Input
P02222 - Powertrain - Throttle/Pedal Position Sensor/Switch B Circuit Low Input
P110D - Powertrain
*P110D - Powertrain

The second code was repeated for some reason....

The battery is charging to about 12.5V when the car is off, but the smart charger is telling me that isn't the full capacity and that it is struggling to get it there.

Anyway, I cleared one last time, cranked, no luck, scanned

PENDING FAULT
P0339 - Powertrain - Crankshaft Position Sensor A Circuit Intermittent

I've now disconnected the battery from the car and have it sat charging via the smart charger, so there are no parasitic drains from the vehicle itself. In the mean time, my old man is heading around with his new Passat which has a huge battery. If I try jumping off that battery, will it eliminate the possibility that it's a battery failure? This worked on a previous Peugeot I had with battery issues, but for some reason I half expect BM's to be a bit more intuitive?

Is there a way of ruling out the battery, so that I can move onto other reasons for this non start ?

Please please please help, otherwise I'll have to buy a banger while this sits on the drive to get me to work

EDIT: Additionally, I scanned with Carly to get some BMW specific codes. Really not sure there's anything there though, most of them seem to be due to low battery rather than like a specific engine fault.... I can post it if you want?