Serious Meltdown

[HobNoxious]

My Mobius Type A/B (I can't remember which) committed suicide by melting, on a cool spring day in the UK - maybe 12 deg C outside, 20deg with the aircon on inside. It had a super-capacitor instead of battery and was permanently powered on in order to make use of the motion sensor as a parking mode. Not unusual usage I'm sure and I didn't expect this to happen...

 

[arcticfire]

Do you know which component failed? The small black chip looks suspect.

 

[nir]

i already saw that meltdowns but not with the capacitor! only with the li-po battery that expands.

 

[HobNoxious]

i already saw that meltdowns but not with the capacitor! only with the li-po battery that expands.

Yes, my LiPo did that about a year ago which is when I changed to the s/cap.

 

[HobNoxious]

Do you know which component failed? The small black chip looks suspect.

I think that's the processor - and yes it looks like it fried for sure - but was it the cause? Looking at the case - wherever there was circuit board underneath, that was where it buckled; so, the whole motherboard got VERY hot. Only the bit behind the lens and ribbon cable didn't warp with the heat.

 

[2000rpm]

Have you managed to salvage the memory card to see when it last recorded anything?

 

[HobNoxious]

Have you managed to salvage the memory card to see when it last recorded anything?

Yes, it came out ok, surprisingly. It was a little melted at the rear edge but came free with a little bit of pushing and picking at with a small screwdriver. The card reads fine on my PC.
There are many gaps in the recording - it seems to have been shutting down randomly and then starting up again after 10-20 minutes - probably after it cooled down a bit.
It was recording off and on during my last trip home, and then stopped completely overnight. My battery was flat the next morning. I think I was lucky it didn't catch fire!

 

[Rajagra]

Looks like you have the rare Salvador Dali edition.

 

[2000rpm]

.....It was recording off and on during my last trip home, and then stopped completely overnight. My battery was flat the next morning. I think I was lucky it didn't catch fire!

So the cam pulled too much power (incorrect/malfunctioning fuse?) - it shouldn't drain your car battery overnight (maybe after four or five days).

What is the cam's power supply arrangement?

 

[Deleted member 46308]

That is some serious heat for sure!

 

[HobNoxious]

So the cam pulled too much power (incorrect/malfunctioning fuse?) - it shouldn't drain your car battery overnight (maybe after four or five days).

What is the cam's power supply arrangement?

Ford Mondeo Mk3 via centre console power outlet / cigarette lighter
Aukey Quick Charge 2.0 54W 4 Ports USB Car Charger Adapter
4m long USB cable routed through centre console and around window frame.

It was in use with a Samsung Note 2 phone and a bluetooth audio receiver - all powered from the USB adapter.
I have been using this setup for over a year now.

The battery drain was due to the shorting out of the camera - presumably it was drawing enough current to generate the heat but not enough to blow the fuse.
The car power socket fuse is undamaged.

 

[2000rpm]

Ford Mondeo Mk3 via centre console power outlet / cigarette lighter
Aukey Quick Charge 2.0 54W 4 Ports USB Car Charger Adapter
4m long USB cable routed through centre console and around window frame.

It was in use with a Samsung Note 2 phone and a bluetooth audio receiver - all powered from the USB adapter.
I have been using this setup for over a year now.

The battery drain was due to the shorting out of the camera - presumably it was drawing enough current to generate the heat but not enough to blow the fuse.
The car power socket fuse is undamaged.

For the car battery to be drained overnight the cam must have pulled ten times its normal amount of power.

I'm wondering whether the power supply has a single fuse which only blows when the adapter's maximum total output of all ports is exceeded (>54 Watts). The cam probably only needed 2 Watts but maybe the adapter allowed it to pull as much as 54 Watts.

I think I would put this meltdown down to a combination of cam malfunction in the first instance, made worse by a power supply that didn't blow a fuse once the power draw exceeded 5-8 Watts which is where a typical dashcam power cable fuse would blow.

 

[reverend]

Bloody hell - I wonder what sort of temperatures that reached to do that to the case?!

I'm tagging @Isoprop - not sure if it's worth sending that back to the manufacturer for fault diagnosis as that looks FUBAR and I think they'd like to inspect this one.

 

[jokiin]

Bloody hell - I wonder what sort of temperatures that reached to do that to the case?!

I'm tagging @Isoprop - not sure if it's worth sending that back to the manufacturer for fault diagnosis as that looks FUBAR and I think they'd like to inspect this one.

from the pics I'd say it's just one of those one in a million type component failures that are unlikely to be repeated, just very lucky it wasn't being used with a battery, I'm sure he wouldn't have got off so lightly if that kind of heat was generated next to a LiPo battery

 

[Rocketvapor]

Yup, one of those one in a million type of failures.
The components on the board side shown look like DC/DC converter parts. Just how many voltages does the Mobius use internally?

The super high powered one size fits all USB 5 v adapter could also be the culprit. A light load (when the Mobius is not actually recording) might not load the USB supply properly, or it could have failed to regulate.
I would check the voltage output to make sure it is working properly.
While these high powered USB supplies are nice and convenient they don't often follow the USB specs for current limiting. More is better, right?

 

[Rocketvapor]

Looking at the specs for your charger is seems to be very smart.
In addition to supplying 5 volts it is smart enough to figure what the battery in your device is and change the output to 9v or even 12 volts if the charger thinks that is what your device wants. Hopefully it never gets stupid or that charging a super cap confuses it.
That would be bad.
Maybe your charger just had a brain fart and tried to charge a 9v device.
Ouch.
Excessive voltage input might be the root cause and would be consistent with the DC/DC converter components in the Mobius overheating.
You might want to contact Aukey and post the pictures to them.

 

[CDNinHH]

5-8 Watts which is where a typical dashcam power cable fuse would blow.

Watts?

Remember your basics.....volts x amps = watts. So 12v x 2 amp fuse =24 watts

I think many people are using a 5a fuse in their fuse taps.....so 12 x 5 = 60 watts. You know how much heat a 60 watt incandescent light bulb can generate....

 

[Rocketvapor]

The USB outputs are often limited by the capacity of the internal DC/DC converter (as long as it is working properly). For a normal dashcam converter you may have a 2 amp fuse to cover dead shorts and to handle inrush current but the little converter in it wouldn't be able to output more than 5V@2A. It's like putting a 20 gal petrol tank on a MoPed. She not go no faster. Now, this 'Smart Charger' likely has a 5 amp input fuse. It would need to live through a startup with a few devices charging at the same time. Each output will be limited to less current.
The specs seem to be:

Specifications:
Input: DC 12-24V 5A Max
Output: 5V/2A, 9V/2A, 12V/1.5A

When putting 5 volts out, it is no different than any other charger.
WHAT IF; charging a supercap didn't force it to 5 volts out. A supercap could easily be used in a 12 volt device if the voltage rating was high enough. What the 5/9/12 volt charger sees is a super cap and a Mobius drawing current at the same time.
I'm sure the Mobius has circuitry to prevent overcharging the Li-ion battery but what would happen to the rest of the circuitry if you put 12 volts straight to it? Even if the charger put out 12 volts for a while then shut down. Would it start up again then shut down, start up, shut down?
What current would the Mobius draw if you put 12 volts straight to it?

I would contact the vendor/manufacturer of the charger and pass the blame off to them.

Just a heads up to those running things from a 'Cigarette Lighter' socket in an American car.
It is likely that the fuse is 15 AMPS for that circuit. The socket, not normally used for lighters will power a small compressor for airing up a flat. Most compressors draw at least 10 amps.
Next time you plug that little USB adapter in there, give it the respect it deserves

 

[Rocketvapor]

I'll post some info that might be helpful with this type of meltdown. (found on internet)
With batteries being swapped out for bigger batteries, or replaced with capacitors the revision level of the Mobius might matter.
Overvoltage protection at the Mobius power connector:

Circuit Board Revision: A new V3 circuit board has been released with an over-voltage protection IC added at the USB plug which will immediately disconnect external power if the applied voltage is between 5.6V and 28V (nominal). This will protect the camera from virtually all of the situations where greater than standard 5V USB power (e.g. 12+ V from a 3S lipo flight pack or FPV TX buss) has been accidentally connected to the camera. This protection IC is ahead of all other camera circuitry, so there will be no indication from the camera when this circuit cuts power. There simply will be no power from the external source. If the camera was already operating on it's internal battery when an over-voltage external supply is connected, it will continue recording on it's internal battery with no help or re-charging available from the external source. NOTE: This IC protection does NOT provide any reverse polarity protection, so it is still imperative that ANY external power connection is not reversed. Doing so will damage the circuitry, as will external power that exceeds 28V. The V3 circuit board will otherwise perform like the V2 board.

It seems the overcharge overdischarge protection for the Mobius is located on the battery. Using a battery without this protection circuit, or maybe a capacitor (?) on an earlier camera without the overvoltage protection circuit could damage the unit if more than 5.5v (upper USB spec) is applied. Other than the name brand Super Cap, do they all have some kind of protection circuit?
I also suspect that using an earlier, unprotected model (without the overvoltage chip) and removing the battery/protection circuit and replacing it with a capacitor could confuse a smart multi-voltage charger. How in the heck would it know to only apply 5V?


It looks like the camera that melted in this thread was a 2013 model.

Do you know the revision level?

It might be a good idea for someone more familiar with the older models to review what I've posted in the past few posts to see if I am totally off course. I don't own one of these and can only apply what I consider to be engineering judgement in forming these opinions. I know there is a Super Cap thread here but Lord, it's over 600 posts long

Hob;
the processor is on the other side of the board.

 

[2000rpm]

Watts?

Remember your basics.....volts x amps = watts. So 12v x 2 amp fuse =24 watts

I think many people are using a 5a fuse in their fuse taps.....so 12 x 5 = 60 watts. You know how much heat a 60 watt incandescent light bulb can generate....

What I meant was that in a regular dashcam power supply unit (and those of phones, satnavs etc), the fuse is usually 1-2A and the power supply output of the charger should be around 5V.
So my assumption was that somewhere between 5-10W going to the cam is where the power supply should blow its fuse, since a normally functioning genuine dashcam adapter should not draw more than 2A and should not output more than 5.25V.

In this instance, there was no fused charger between the cam and the 12v * 4.5A quadruple socket because the USB cable was plugged straight into the multi-socket adapter.