Mustang 5.0 Jump Start - Problem Solved

The day before our Euro road trip I went to take the Mustang out and I could open the doors and turn on the ignition as usual but the engine wouldn’t crank as the battery was low voltage. I had driven just 4 days previously so it was a bit of a surprise. Fortunately the first-year service had extended the Ford Assistance cover for another year and the nice man from the AA soon had us running again.

The AA man also measured the ignition-off battery drain which was a couple of Amps which is a bit of mystery as the dashcam was disconnected by now and one possible culprit could be the tracker.

Being about to depart for our Euro trip I was a little nervous of a repeat episode so I decided to invest in a jump starter. I do leave the Mustang standing for extended periods and often much longer than 4 days so I had looked at these devices previously and there is a choice of big bulky lead acid and newer small and sleek Li-ion but none are recommended for engine up to 5000cc.

I decided on the Streetwize 14000 MAH Power Bank and Jump Starter from Argos £89.99 as this device specification is rated significantly higher than alternative devices and at least it should be easy to return.

It is stated that this unit is suitable for petrol engine up to 3000cc and diesel engine up to 2500cc

The significant specs are
Capacity 14,000 mAh
Start Current: 300 Amps
Peak Current: 400 Amps

Unfortunately it is not possible to simulate the conditions to fully test a jump start so I had to wait for a real emergency which occurred today…

I had left the Mustang standing for 6 days and went to open the trunk using the fob but these was no response. I tried to open the driver’s door and again no response. It was a totally flat battery this time. After a few minutes experimentation I managed to slide the little cover off the door handle and used the emergency key to open the door. The start button triggered some odd indicator lights behaviour and nothing else. Unfortunately the jump starter was stored in the trunk and inside the spare wheel well so I got the back seats down and managed to retrieve the storage box containing the jump starter. Next the hood was popped open and the battery cover removed. The jump leads were attached (red to red, black to black). As soon as the jump leads were connected to the jump starter the alarm triggered so I got inside and pressed the start button. The first start attempt produced some starter activity but the cranking stopped. The second start attempt worked straight away and the engine roared into life.

Before use 4 out of 5 battery charge indicator lights were lit and after use 4 out of 5 lights were still lit so I expect the jump starter would have worked for another attempt.

So there is proof. The Streetwize 14000 MAH Power Bank and Jump Starter from Argos £89.99 does start a Mustang 5.0 V8 from a totally flat battery. I never leave home without one.

It also charges iPhones

Something definitely not right with your battery mate. Mine can stand for 3 weeks and start with no issues.
I had a lot of issues with my transit doing the same. If you left the rear doors open for anymore than 10 mins the battery would die. Worth having it tested and replaced. Not sure if warranty would cover it or not?

With the ignition off something is drawing a couple of amps but what could it be?

I do have a tracker fitted but I don't know where it is located or what it looks like. When I was hardwiring the dashcam I did find a soldered splice already made into the wiring loom near the internal fuse box. I might trace that back and see of it is for the tracker.

Yep, something is drawing current for sure. I just left mine laid up for a month and it started no problem, cranking at the usual speed surprisingly.
ive had cars with trackers before with no issues, worth checking the boot light isn't staying on.

2 amps is a lot

A simplistic calculation says that on a 60 amp hour battery a 1 amp draw will last for 60 hours, so in theory your 2 amp draw will kill your battery after 30 hours...

In reality it will be flat much sooner, because once the voltage gets lower the car won't start..

Enoch said:

2 amps is a lot

Click to expand...

The AA measured the current using an induction loop so it may not be an accurate 2 Amps but it the load is enough to flatten the battery after a few days.

I have previously left the Mustang standing for several weeks with no issue so it is a recent development.

Another possibility is the dashcam parking mode not cutting out at low voltage. The dashcam was connected on both previous flat battery incidents so it is disconnected now and I will see what happens in a few days.

I had a completely flat battery last November (or thereabouts) after sitting for maybe 2 weeks, but it has never repeated - even after sitting for over 3 weeks at one point.

So maybe "something played up" and is now "playing nicely"... It doesn't instill a huge degree of confidence but mine has been fine for around 9 months now...

not sure but are you able to assess the battery amp draw and remove the fuses one by one to see which system is drawing?

It is stated that this unit is suitable for petrol engine up to 3000cc and diesel engine up to 2500cc

The significant specs are
Capacity 14,000 mAh
Start Current: 300 Amps
Peak Current: 400 Amps

Unfortunately it is not possible to simulate the conditions to fully test a jump start so I had to wait for a real emergency which occurred today…

I had left trter activity but the cranking stopped. The second start attempt worked straight away and the engine roared into life.

Before use 4 out of 5 battery charge indicator lights were lit and after use 4 out of 5 lights were still lit so I expect the jump starter would have worked for another attempt


It's possible to try it you disconnect the battery and clamp pack in place ,this is how I tried mine on a Dodge Ram 5.7ltr, mine is rated upto 6000cc petrol

Symone said:

It is stated that this unit is suitable for petrol engine up to 3000cc and diesel engine up to 2500cc

The significant specs are
Capacity 14,000 mAh
Start Current: 300 Amps
Peak Current: 400 Amps

Unfortunately it is not possible to simulate the conditions to fully test a jump start so I had to wait for a real emergency which occurred today…

I had left trter activity but the cranking stopped. The second start attempt worked straight away and the engine roared into life.

Before use 4 out of 5 battery charge indicator lights were lit and after use 4 out of 5 lights were still lit so I expect the jump starter would have worked for another attempt


It's possible to try it you disconnect the battery and clamp pack in place ,this is how I tried mine on a Dodge Ram 5.7ltr, mine is rated upto 6000cc petrol

Click to expand...

I'm not sure what you mean. I couldn't test it in advance of getting a flat battery but when the battery was flat to the point that central locking didn't work the jump start did start the engine.

Mystery Solved

Previously the battery on the Mustang seemed to be going flat after a few days standing parked up but today the Mustang has been standing for exactly 1 week without running so it was a good time to test if the battery was holding out.

The first sign of good news to come was that the central locking working OK, I quickly checked the battery voltage which was 11.2 Volts and is consistent with previous successful starts and then I hit the brake and pushed the start button and the engine started first time.

One possibility for causing the battery drain was the Thinkware F750 Dashcam. The F750 has a parking mode which for me usually only lasts a few hours before the battery low voltage causes it to shut down and for previous flat battery situations the F750 had been left active when parked. This time when I parked up I had disconnected the F750 and this time the engine started no problem.

Retrieving and examining the contents of the Thinkware F750 memory card I noticed that some of the continuous recording was dated prior to my previous flat battery. This continuous recording was night-time and very early morning when the car was parked up so the F750 should have been in parking mode and not continuously recording.

One feature of the F750 is to display the battery voltage in the video and over the last few hours continuous recording the battery voltage dropped from 10.6 Volts on the oldest video down to just 5.9 Volts when I assume the voltage was too low to sustain life and my Mustang was effectively dead.

So it seems that for some reason the Thinkware F750 had stayed in continuous recording mode when it should have been in parking mode and should have shutdown then the voltage dropped.

I have checked the Thinkware F750 settings and parking mode is enabled and the Battery voltage setting for stop recording is at the lowest 11.6 Volts but this setting has not caused any issues over the previous 18 months of ownership.

So it appears that the Thinkware F750 Dashcam is the culprit for the flat battery. I will connect it back up next time I'm out in the Mustang and monitor parking mode - and cue me dashing out every few minutes to see it has shut off yet.

One thing worth thinking about is that shortly before my Mustang flat battery episodes began I had used the Thinkware F750 Dashcam PC Viewer application to view some video and had been offered a firmware upgrade which I allowed to install. Possibly there was an issue with that firmware version and interestingly I was just offered another firmware upgrade as I was investigating this problem.

Just one small mystery now remains which is what was drawing the "couple of Amps" as measured by the AA man as the Thinkware F750 had been disconnected while trying to troubleshoot the battery problem. Possibly for the Mustang there is a current drain for a period after ignition off but possibly it doesn’t continue for a long time.

Actual said:

Mystery Solved

Previously the battery on the Mustang seemed to be going flat after a few days standing parked up but today the Mustang has been standing for exactly 1 week without running so it was a good time to test if the battery was holding out.

The first sign of good news to come was that the central locking working OK, I quickly checked the battery voltage which was 11.2 Volts and is consistent with previous successful starts and then I hit the brake and pushed the start button and the engine started first time.

One possibility for causing the battery drain was the Thinkware F750 Dashcam. The F750 has a parking mode which for me usually only lasts a few hours before the battery low voltage causes it to shut down and for previous flat battery situations the F750 had been left active when parked. This time when I parked up I had disconnected the F750 and this time the engine started no problem.

Retrieving and examining the contents of the Thinkware F750 memory card I noticed that some of the continuous recording was dated prior to my previous flat battery. This continuous recording was night-time and very early morning when the car was parked up so the F750 should have been in parking mode and not continuously recording.

One feature of the F750 is to display the battery voltage in the video and over the last few hours continuous recording the battery voltage dropped from 10.6 Volts on the oldest video down to just 5.9 Volts when I assume the voltage was too low to sustain life and my Mustang was effectively dead.

So it seems that for some reason the Thinkware F750 had stayed in continuous recording mode when it should have been in parking mode and should have shutdown then the voltage dropped.

I have checked the Thinkware F750 settings and parking mode is enabled and the Battery voltage setting for stop recording is at the lowest 11.6 Volts but this setting has not caused any issues over the previous 18 months of ownership.

So it appears that the Thinkware F750 Dashcam is the culprit for the flat battery. I will connect it back up next time I'm out in the Mustang and monitor parking mode - and cue me dashing out every few minutes to see it has shut off yet.

One thing worth thinking about is that shortly before my Mustang flat battery episodes began I had used the Thinkware F750 Dashcam PC Viewer application to view some video and had been offered a firmware upgrade which I allowed to install. Possibly there was an issue with that firmware version and interestingly I was just offered another firmware upgrade as I was investigating this problem.

Just one small mystery now remains which is what was drawing the "couple of Amps" as measured by the AA man as the Thinkware F750 had been disconnected while trying to troubleshoot the battery problem. Possibly for the Mustang there is a current drain for a period after ignition off but possibly it doesn’t continue for a long time.

Click to expand...

I have a F750, i have it set for 48 Hours in parking mode, it usually runs for around 24 to 30 hours, and the battery voltage when i get into the car, after 5 days sometimes, will always be around 10.06
Never had any issues, and that is running front and rear dashcams
Mind you I never hardwired it, the company who imported the car and done my lights did.
And |I done the firmware upgrade last week and no issues since
I think you should look at your tracker, is that signal not on 24/7 ?