I decided to connect my 12v charger because I recently bought OBDeleven and didn't want to run the engine for hours whilst I played wth the App....

I've now done this multiple evenings and left it charging overnight (Ctek MXS 3.8 charger)

I noticed belt squeeling during every warmup since and I now think the alternator has been over loading itself

I realise I should have been using the negative teminal on the bulkhead to charge. I was wondering is there a way I can now reset the BMS without taking the terminals off, it's a new car and I didn't want to cause any extra issues by disconnecting.... it was bought in August (2.0 TDI)

Your error with the negative charging lead will not be the cause of the auxiliary belt squeal - get the belt tensioner and belt checked.

Edited 1 November, 20251 Nov by Warrior193
correction

9 hours ago, Warrior193 said:

Your error with the negative charging lead will not be the cause of the auxiliary belt squeal - get the belt tensioner and belt checked.

I'm happy with the belts thanks, I don't know why I said squeal, it's the tiniest chirp, I guess I could have looked up the alternator loading on OBDeleven but I've done all my own maintenance on my cars (Subaru's) since 1990 which is probably why I had an ear for it...

Can you confirm what car you have? There is no 4.5 TDI

Car is 2.0TDi purchased new (Mk 4.5) and about 4 months old (DXRB engine) and the most basic trim level, my original query was whether I can reset the BMS (without disconnecting the battery) because by charging it incorrectly multiple times, I've stuffed it up and given it false information...

---------------------------------------------------------------

03 Brakes

System description: ESC

Software number: 5WA614517DQ

Software version: 0331

Hardware number: 5WA********

Hardware version: H31

Serial number: 6144*******

ODX name: EV_Brake1***********NECE

ODX version: 006026

Long coding: 52185228A48B***************

Trouble codes:

U140000 - Function restriction due to insufficient voltage

Intermittent

17 hours ago, KinderBean said:

Car is 2.0TDi purchased new (Mk 4.5) and about 4 months old (DXRB engine) and the most basic trim level, my original query was whether I can reset the BMS (without disconnecting the battery) because by charging it incorrectly multiple times, I've stuffed it up and given it false information...

---------------------------------------------------------------

03 Brakes

System description: ESC

Software number: 5WA614517DQ

Software version: 0331

Hardware number: 5WA********

Hardware version: H31

Serial number: 6144*******

ODX name: EV_Brake1***********NECE

ODX version: 006026

Long coding: 52185228A48B***************

Trouble codes:

U140000 - Function restriction due to insufficient voltage

Intermittent

Sorry my bad I was assuming you meant RS which is why TDI confused me. Can’t you just ask the dealer to do it? To be honest I wouldn’t be messing around with a new car, leave that to when it’s out of warranty.

no worries, someone I know who works in auto said don't approach a dealer and say you've charged it, else it will blow away your warranty. I'm not looking for a new battery etc.... just to reset the BMS

you can only manipulate with BMS changing battery parameters, but its to be done only when change battery.

or disconnect battery for few minutes, you cant disconnect on baterry terminal but can on terminal in fusebox.

Edited 4 November, 20254 Nov by imart143