Hi Dave (I assume),
Welcome to our "Thread of Disappointment" with the Epson
BT-300. I have been tied up with a consulting job for the last several weeks and not been around. I see that Davo101 has about had it with the heat issue. Its sad but he is correct. You cannot trust the BT's and Murphy says the glasses will crap out on you at the worst possible time. I hope Davo still has time left on his return so he can get his money back. And as Davo mentioned Epson is of no help what so ever. They will not even acknowledge us on this thread or my several emails. Very sad! I guess this is why DJI no longer is recommending or supporting the glasses. When I asked for help on the DJI site I was told by DJI to only use DJI approved equipment. I guess they may have split the sheets. Great idea but not quite ready for prime time.
The other day I was out flying and monitoring the temperature of the BT's. Outside air temp was 35C (95F) BT's 28C (82F) After 20 minutes of flying the BT's temperature increased to 53C (127F) way too HOT!!!!!. The BT spec claims operation up to 35C. I was not using a fan or any type of cooling what so ever. The BT's did not shut down but is was showing an OVERHEAT and the battery had stopped charging. At this point if I were to change batteries on the bird and restart everything I would have got the charger error and the BT's would have shut down.
Perhaps if there was a way to disconnect the internal battery on the BT's and run them from an external source we could reduce some of the internal heat. When operating with DJI GO and there is approximately 1200mA of current required. The DJI controller is limited to 450mA so the BT's battery must supply the rest. Approximately 800mA from the battery coupled with the heat generated by the CPU produces a lot of heat.
I was playing with a Peltier device. Basically it is a solid state cooling device. I have used them in medical equipment designs in the past. They can get cold enough to freeze water. Only major problem is take a lot of power to operate. The side with the heatsink and fan gets hot while the other side gets cold. The peltier is the white thingy between the 2 heatsinks. A fan is required the cool the heatsink. I was using a 12 volt peltier but running it on only 3.7 VDC. At that voltage it still draws
3.5 Amperes.
Anyway here is what I tried.
It does work and keeps the temperature around 32-35C but one would have to carry a large battery to power the peltier device and I for one do not want to carry any more weight with me when I fly. The cold side plate in contact with the BT's gets down to approximately 18-19C but the thermal transfer between the BT's rear plastic case and its internal components is, at best, poor.
If I can find some time I would like to design on a all aluminum back cover for the BTs with peaks and valleys to contact all the heat generating components and provide a proper heatsink to the outside world.
The long solution remains with Epson and until it has been corrected I will only fly the BT's for no longer than 15-20 minutes. After that its back to a standard phone display. Perhaps a DJI
Crystalsky is in order.
About using the other connector on the
MA, If there is no 5 volts present the BT's will not see the data. I tried limiting the current using a resistor but still allowing the BT's to detect and process the data for video. It did help but not enough. The best possible solution for you at this point would be to add a small fan as I and several have done. It will help, but again, it is band-aid and to a total solution.
~Bill
