Battery power whilst updating firmware (NOT VW but Audi)

[Ayjay]

A bit of a silly electrical question but I'm an idiot when it comes to this sort of thing. I've got the 2022 SD cards on the way to update the firmware and maps in my Audi Q5 stereo/sat nav system (aka Audi MMI 3G+). I'm happy that it's should be a straightforward enough job to do but I'm concerned about the starter battery in this weather. Apparently, the whole operation can take up to 2 hours and the ignition needs to be on the whole time but I don't want the battery to run down midway through the update and risk bricking the system. As I see it, my options are to start the engine and just leave it running for the whole time OR plug in my Ctek MX5 charger and just leave that feeding juice into the battery without the engine running but with the ignition on. I prefer the latter if it would work but any advice much appreciated.

 

[Dav-Tec]

We usually hook the vehicle up to a stabilised 12v power supply but the issue you will have is do you know the input power of your charger? If the input is greater than the drain you will be fine.

 

[Dellmassive]

yes - you need to use the Mains charger for this. . . .

just connect up the CTEK MX5 and leave it running until the process is complete.


it will help if you switch all the extras stuff off while doing the procedure. . .


ie lights, seats, etc etc

 

[Dellmassive]

We usually hook the vehicle up to a stabilised 12v power supply but the issue you will have is do you know the input power of your charger? If the input is greater than the drain you will be fine.

a very good point, thats worth noting.

the CTEK MX5 is a 5A charger. . .


so the MIN size recomended me thinks.

MXS 5.0 UK

56-975

www.ctek.com

Technical data​

Input220–240 VAC, 50–60 Hz, 0.6 A
Output14.4/14.7/15.8 V, 5.0 A
Battery capacity1.2–160 Ah
Charging categoryAC charging
Back current drain*Corresponding to less than 1 Ah/month
Battery voltage12 V
Battery chemistryLead acid
Ambient operating temperature-20 ˚C to +50 ˚C
Start voltage2.0 V
Ripple**Less than 4 %
Battery types12 V:; WET; MF; Ca/Ca; AGM; GEL
Degree of protectionIP65
Warranty5 years

 

[Dav-Tec]

Last time I clamped one with just the absolute bare minimum on it was around 12A draw. Our charger is 30A so all good but just conscious with the radio on too the could be quite a deficit

 

[Ayjay]

@Dav-Tec @Dellmassive. Cheers guys - I expected one of you to pop up with sound advice but maybe not that quickly! So the choices seem to be switch absolutely everything off in the car, plug in the Ctek MX5 and cross fingers or leave the engine running for the whole time. Is there any advantage or, indeed, danger in doing both?

 

[Dav-Tec]

If you loose.power to the vehicle you can brick the unit. Then you have to send it to some one like me for repair... If It can be repaired...

I'd just keep the engine on and watch Netflix on your phone. Usually done within an hour or less

 

[Dellmassive]

good advice above.

 

[Ayjay]

Cheer again chaps - l will take your advice.