S550 battery drain

[Joe5oh]

Hey guys I recently bought a 2018 mustang Gt PP1 10 SPD FBO and absolutely love it. For some odd reason the car keeps dying over night it’s happened about 6-7 times within two months and needs to be jumped. I purchased a new battery about a month ago and the problem hasn’t stopped. There’s clearly some electrical issue drawing power when it’s off has anyone had this issue?

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[80FoxCoupe]

Is the car all stock? Any added electrical equipment?

 

[Cobra Jet]

Hey guys I recently bought a 2018 mustang Gt PP1 10 SPD FBO and absolutely love it. For some odd reason the car keeps dying over night it’s happened about 6-7 times within two months and needs to be jumped. I purchased a new battery about a month ago and the problem hasn’t stopped. There’s clearly some electrical issue drawing power when it’s off has anyone had this issue?

Read this thread - specifically the update in Post #14 .... see if that may be your issue too.

https://www.mustang6g.com/forums/threads/misfire-on-startup-constantly-dead-battery.184938/

 

[SheepDog]

Hey guys I recently bought a 2018 mustang Gt PP1 10 SPD FBO and absolutely love it. For some odd reason the car keeps dying over night it’s happened about 6-7 times within two months and needs to be jumped. I purchased a new battery about a month ago and the problem hasn’t stopped. There’s clearly some electrical issue drawing power when it’s off has anyone had this issue?

The only way to be sure is to perform a parasitic draw test. Anything from a dome light being left on, to door latch issues, to an aftermarket Amp can cause this.. Any accessories like hard wired radar detector, stereo amplifier, additional lighting etc?

 

[Joe5oh]

Thanks for the response. I Have not added anything aftermarket electrical that would draw from the battery. I did notice when I purchased the car the signal light bulbs along side the fog lights aswell were unplugged which was interesting.. I performed a BMS on it today as ford advised hopefully that will resolve it but I doubt it.

 

[Pucklord]

Do a battery rest I think you can find the steps on YouTube also check the light inside the armrest make sure it's turned off I had similar issue with it before and I fix it. I wrote a thread about it.

 

[Skye]

The lights being disconnected are concerning and could be a tell, yes.

Any history of the car? Number of previous owners? Locations? Service?

Thanks.

 

[djcodeman]

might be the FOB proximity sensor pinging the electrical system

 

[Joe5oh]

Is the car all stock? Any added electrical equipment?

might be the FOB proximity sensor pinging the electrical system

You think there may be a chance it’s locking and unlocking the vehicle and draining the battery? Do you think just pulling the batteries from the fob and using the spare may fix that issue?

 

[djcodeman]

You think there may be a chance it’s locking and unlocking the vehicle and draining the battery? Do you think just pulling the batteries from the fob and using the spare may fix that issue?

Worth a shot... the proximity sensor is just always searching to see if the fob is close...

 

[SheepDog]

If a new battery that is fully charged is going completely dead overnight, you have a fairly substantial draw. Was the car ever in a wreck?

 

[KingKona]

Has the new battery had a nice, long (hour +) drive to fully charge?

 

[Joe5oh]

If a new battery that is fully charged is going completely dead overnight, you have a fairly substantial draw. Was the car ever in a wreck?

 

[Joe5oh]

No the car has a clean car fax and I’ve even delved into its visits to ford and work that was done and nothing indicates there was an issue up all the way up from 2018 to Jan 2022 I’m unable to see anything after that though. I did the BMS reset and changed the fob. Cars running fine hopefully this eliminates the problem. If it happens again I’ll have to just do a parasitic draw test and take out each fuse one by one which I’ve been trying to avoid due to being so time consuming.

 

[Joe5oh]

No the car has a clean car fax and I’ve even delved into its visits to ford and work that was done and nothing indicates there was an issue up all the way up from 2018 to Jan 2022 I’m unable to see anything after that though. I did the BMS reset and changed the fob the car also ALWAYS stays at 14-14.5V while running and then randomly just dies. Cars running fine for now hopefully this eliminates the problem. If it happens again I’ll have to just do a parasitic draw test and take out each fuse one by one which I’ve been trying to avoid due to being so time consuming.

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