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Mid-air BT-300 system shut down 'USB CHARGER ERROR' - HELP!

I have just come back from Thailand, April is the hottest and has the highest humidity. My glasses never shut down once flying a P4Pv2 and Mavic 2. The r/c got hot but never shut down once. In the past I would definitely have bought a fan/cooling system, I don't need one now. The BT glasses work in very hot and humid conditions now. Software improvements have solved my issues.
 
My pleasure David,

I re-ran my experiment using an external power supply this time and discovered that a 30 ohm resistor in series with 5VDC Vcc will indeed reduce the charge current. What threw me for loop yesterday was I expected the LED's on the Moverio's to stop flashing but still communicate. When I lowered the Vcc to a point where the LED's did stop flashing the BT-300's USB port would shut down and disconnect from the controller. My mistake was the LED's will flash whenever the BT-300 detects a voltage above ~ 3.5 VDC on the Vcc line. It is simply telling you there voltage present on the connector. The nominal Vcc coming from my controller with a full charge was 5.14 VDC. At this voltage (full charge) the charge current was ~450 mA. At 450 mA my BT-300's began to heat up. Not hot, but getting warm. After several iterations I finally settled on a 30 ohm resistor and a charge current of 22 mA. With a higher value resistor I could even get the charge current down to 0.0 mA but I wanted to be sure the BT-300's always have enough voltage so as not to connect. I let the system run for almost an hour and the BT-300 remained cool to the touch. I know this is a work-around solution but its the best we can do without rooting. Hopefully Epson will develop a software fix SOON.

This is a simple thing to do. Take which ever cable and cut a 2 inch slit in the outside jacket being careful not to cut into the wires inside. If there is a braided shield try to spread it so you can gain access to the foil shield. Remove the foil shield and discard. There should be 4 wires inside the cable. A red, a black, a white and a green. I would use a volt meter and verify the Vcc is the red wire and the black is the ground. Just make a voltage measurement between the black and red and you should read 5 VDC. This is just to verify whomever made the cable followed standard color code. It is possible they did not. Then simply cut the red wire and insert the resistor. One red wire to one side of the resistor and the other red wire to other side of the resistor. Use heat-shrink to insulate your connections making sure the neither side of the resistor can come in contact with the braided shield.

I can do a picture if you like, just no time tonight.

I have half a notion to make a simple connector with the resistor already installed and offer it for sale. There are lots of android users complaining about their phones getting hot due to charging.
Brilliant idea, do you take paypal, LOL. Nice work sir.
 
What a true pro - many thanks for your tenacity.
 
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After some tinkering tonight I might have solved the problem. Just make sure you turn on drone first and controller second. Make sure the BT-300 is already connected to the controller via USB and then turn it on and make sure you already set it to load DJI4 by default every time you turn it on. Make sure you follow this procedure every time you put a new battery in the drone. So far so good.
 
After some tinkering tonight I might have solved the problem. Just make sure you turn on drone first and controller second. Make sure the BT-300 is already connected to the controller via USB and then turn it on and make sure you already set it to load DJI4 by default every time you turn it on. Make sure you follow this procedure every time you put a new battery in the drone. So far so good.
May I ask what firmware version your BT-300 smartglasses are on (ie. v1.5). And what version DJI GO4 app you have loaded on your BT-300 Android controller (ie. v4.3.24).

Thank you!
 
I have had the same problem. I am going to try this procedure. Has anyone tried using the side port instead of the USB port to connect the Epson to the controller.
 
I have had the same problem. I am going to try this procedure. Has anyone tried using the side port instead of the USB port to connect the Epson to the controller.
There are 3 things I did that cured my overheating problems:
1. Use a better microUSB cable such as the Anker Powerline.
2. Disable video caching in GO4 app.
3. Set resolution to Normal (not HD) in BT300 Android controller.
 
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There are 3 things I did that cured my overheating problems:
1. Use a better microUSB cable such as the Anker Powerline.
2. Disable video caching in GO4 app.
3. Set resolution to Normal (not HD) in BT300 Android controller.

I agree those are all good things to do as well. I never altered the resolution settings and still have them in HD since I haven’t had any problems recently. Does reducing resolution reduce any lag or has it only been effective in reducing heat in your case?

I also changed my micro USB cord to this angled one which works and fits so perfect. https://www.amazon.com/dp/B01LX0IF95/ref=cm_sw_r_cp_api_i_a.5cFbK7NF4ZP
 
I agree with the above points, also.
The problem of overheating is two fold. High temperatures and high humidity. I found if one element was not there it is not a problem.
So keep it out of the sun on warm days. If you can turn your back to the sun and or get a shade, they are not expensive. Practice a quick switch to a phone or tablet if the Bt's r/c overheats and bombs out. It happened to me a lot in Thailand when the temp and humidity was high. If you fly for long periods rest the r/c and use a phone to let it cool down. I have been a bit of an idiot and taken a cooler pack to transport the r/c and between batteries.
I bought my recent ones so in autumn and winter so no issues as yet in Australia.
 
Does reducing resolution reduce any lag or has it only been effective in reducing heat in your case?
Reducing resolution reduces lag because your Moverios don’t need to display as many pixels in NORMAL versus HD. But it goes without saying that if the BT300’s processor is being overworked, the result is more heat generated.
 
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Reducing resolution reduces lag because your Moverios don’t need to display as many pixels in NORMAL versus HD. But it goes without saying that if the BT300’s processor is being overworked, the result is more heat generated.
I haven’t had any major lag issues in HD so far. However I have kept most of my flights within the 1500ft range. I might give the reduced resolution idea a shot if lag starts to become more of an issue the further I venture out.
 
Did some more research. To add to all the suggestions above, you can go into the BT300's Android controller under SETTINGS > APPLICATIONS and STOP any running applications that are using up memory such as Moverio Store, Web Browser, etc. I stopped everything except Android Keyboard. At that point I had 1.3GB of FREE Memory!
 
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