Burned my fingers

Discussion in 'SJ7 Star' started by RBEmerson, Feb 20, 2018.

  1. RBEmerson

    RBEmerson Humbled by events

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    After using my SJ7 as a dash camera for about five hours, I tried to power it down. No luck - it was "pull the battery" crashed. I opened the case, tilted the camera onto the back, and picked it up with my thumb and forefinger. Three hours later my thumb and finger tip are still red and sensitive. These are the symptoms of first degree burns.

    The camera is now retired from service at the start of a month-long road trip. I am not amused.
     
  2. nianeko2

    nianeko2 Member

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    Unfortunate! Did you used "Waterproof Motorcycle Charger Case"?
     
  3. RBEmerson

    RBEmerson Humbled by events

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    Thank you.

    I used the case as a test of how the camera would work during the prime motorcycle season. I expected the camera to get hot, but this was way beyond what I anticipated.

    In addition to the physical risk, there's also the risk of catastrophic battery failure Overheating is a common failure mode.

    At this point the camera will be used for time-lapse work and that's it.

    It was fun while it lasted, but I'm done with the camera.
     
  4. nianeko2

    nianeko2 Member

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    Now you are in summer, and used under hot circumstance?
     
  5. RBEmerson

    RBEmerson Humbled by events

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    Right now we're in northern Florida and the daytime temperatures are only about 24-26C ("mid-70's"). The problem is lots of sunshine and the camera was "looking" through the windshield. I can't measure the temperature near the case, but assume it's at least 5-10 C hotter (probably more). Since the camera can reach 57 C (135 F) in free air while running at 1080@60 fps, reaching 65-70 C / 150-160 F is likely. My fingers can attest to that .
     
  6. nianeko2

    nianeko2 Member

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    I enjoy your beautiful YouTube videos every time.
     
  7. RBEmerson

    RBEmerson Humbled by events

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    Thanks! Those videos were shot with the same camera.

    Last July the motorcycle case wasn't available so I had to use the frame mount. I consider myself lucky that dirt or moisture didn't get inside the camera. Obviously the case acts like a greenhouse taking heat in, but letting it get out.

    I told SJCam about the earlier heating results. The response was "if it's hot, don't use it." Advice accepted...
     
  8. nianeko2

    nianeko2 Member

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    So this case can only use at North or South Pole.:)
     
  9. RBEmerson

    RBEmerson Humbled by events

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    Let's put it this way, if the penguins and polar bears are wearing sweaters to stay warm, it's probably OK. [/wink]
     
  10. RBEmerson

    RBEmerson Humbled by events

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    Following up...

    I've spent some time shooting with my GoPro Hero 5 Black. The "30 minutes shooting 1080@60" test that had the SJ7 well into the "hot" range (135F / 57C) brought to the H5B to "somewhat warm" (no IR thermometer gun handy). Overall, this camera is significantly cooler, even with a "rubberized" exterior versus the SJ7's metal frame.
     
  11. Delta Echo

    Delta Echo New Member

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    I read some of the heating complaints when reading reviews (before buying my SJ7), but since my primary intended use is snowmobiling, I wasn't overly concerned with it. But it makes me wonder about how long the camera will last...

    I am also going to try it for some kayaking and mountain biking this summer, so I hope it lasts until winter. How long is that warranty? o_O
     
  12. RBEmerson

    RBEmerson Humbled by events

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    The short answer is "it depends on the ambient air temperature". Snowmobiling shouldn't be a problem. Kayaking and bikes in moderate conditions and no protracted baking in the sun may work.

    Life span? My guess is it's going to be disappointingly short. Particularly for the batteries. They swell after protracted heating and that presents the possibility of catastrophic failure as swelling forces parts together, creating an internal short and... poof!
     
  13. Delta Echo

    Delta Echo New Member

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    So what is GoPro doing differently to combat the heat buildup?
     
  14. RBEmerson

    RBEmerson Humbled by events

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    I don't know. The case is coated with some sort of non-skid material (not bare metal), which reduces dissipation. About all I can think of is tuned firmware that pushes the electronics less than the SJ7, and components with lower operating temperatures.

    However, all of this comes at a price. Compared to the SJ7, the imagery sux. Too much strobing when, for example, there are shadow stripes or tar stripes on the road. Grass, etc. on the side of the road is less distinct. I'll get a side by side demo up in a few days.

    Bottom line: if the SJ7 didn't cook itself to death, it would be a distinct winner over the Hero 5.

    @Everybody - Please don't use this thread and post to start a debate about GoPro products. Wait for my new thread, or start one.
     
  15. HR-Mike

    HR-Mike New Member

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    My personal thoughts ...

    Let's start with the comparison of GoPro 5 Blk Vs. SJ7 STAR on chipset level.
    Ambarella A9SE Vs. A12S75 ... and if we use them at the same resolution eg. 1080 @ 60 SJ generates the same or even less heat in the same circumstances (newer chipset).
    But, what if the heat of a SJ case comes from the fact that actually it has a better solution of component cooling. What if it constructed to completely transfers the heat to the aluminum housing - which is actually an excellent cooler?

    Excessive heating of the case may not be as bad as it looks.
    Simply, the more heat out of the case gives the less heat inside of the case, which eventually leads to the longer life span of its components.
     
  16. RBEmerson

    RBEmerson Humbled by events

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    Simply put, the Ambarella chip runs hotter than the A12S75, right? Each camera has its existing heat sink. Each camera's case must (laws of thermodynamics) reach thermal equilibrium. The camera with the hotter heat source (video chip) is going to be hotter because it's going to take time to reach equalibrium. There's no way around that. There's no option for the SJ7 to dump more heat and reach equilibrium with the air around it faster than is already the situation.

    The aluminum frame people have gotten excited about doesn't have a good fit with the SJ7 - the frame's larger than the SJ7. Unless there's an aluminum spacer around the SJ7, the frame is going to be slower to reach equilibrium. There's no way around that. Additionally, the frame does nothing towards waterproofing the SJ7. It won't fit inside the waterproof cases. In short, without re-engineering the frame, it's not going to do a good job of cooling the SJ7, and it leaves the SJ7 as open to damage from rain, melting snow, dust from trails, etc., etc. Bad idea.

    The SJ7 case isn't going to be changed. The only hope is getting the Ambarella chip running at a lower temperature. Changes in firmware might, or might not, help here. Anything else is wishful thinking. Adding some heat transfer through the case will probably help lower the SJ7's temperature in a case, but unless the case's heat sink area is at least as great as the SJ7's aluminum case, the SJ7 will still be hotter than without a case. |That's why I burned my fingers.

    Or... it is what it is, and it's not going to change any time soon, if at all.
     

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