I have a Brain2 HD on one of my helicopter that is equiped with an Opti Guard. I forgot turn the Opti Guard off when I completed my last flight and its battery died.
When I went to power up the heli for another flight, the Brain2 would not work. No LEDs would come on for at least 10 seconds after power was applied, and then the RED LED comes on solid.
I took it home and plugged in to my PC and it immediatley said the firmware was out of date. I know for a fact it did have the latest firmware.
I allowed the PC apps to re-flash the gyro and now it seems to be working again, although I am pretty sure some of the recent parameter settings I made had reverted to an older setup.
The logs do show many 4.3V under voltage events, but no other entries that would sugegst a firmware corruption.
Can someone shed some light on what may have hapened and should I be concerened about using this gyro in the furture?
Thanks
Shawn
I'd say you were very, very, very lucky.
As you may know, when a Lipo discharges completely, it overheats and is damaged. Often irreparably.
Sometimes internal chemicals generate gas and the Lipo swells. If the casing swells, the internal chemicals in contact with the air may catch fire.
The same risks are incurred when recharging a Lipo that has fallen below the minimum safety rating of 3.3V without following proper procedures.
When a Lipo is completely discharged, you should try to recharge it very slowly with a battery charger and not on board the model, keeping it constantly under control.
It should then be verified that the Lipo has not been damaged by full discharge but that it works otherwise instead of being a backup power system it could only be a load connected to the BEC that would only discharge the main battery faster and could reduce the power supply voltage of the model.
Powering the model with the battery completely discharged, the BEC had to deliver a charging current higher than the maximum deliverable and then the output voltage of the BEC collapsed and then slowly climbed while the Lipo recharges. You write that the Brain only turned on after ten seconds (but I think it took more than 10 seconds). During these ten seconds (or more) the microprocessor was powered at an unregulated voltage lower than the normal operating voltage and the internal circuits of the processor will not be correctly initialized causing malfunctions of the ram that will be dirty. For this reason, the boot software will have considered the firmware invalid and has waited for a new valid firmware to be rewritten (red led on steady).
The Brain parameters should NOT have changed because they are written in a different and protected ROM memory area.
If you now find that the values are not configured correctly, then they were not configured correctly even before.
This whole process is normal, and it is expected and after rewriting the firmware in the unit everything is back to working properly as before.
The cause of everything that has happened is not the Brain2, but the fully discharged backup battery connected to the power supply of the BEC like a very, very high load.
If you still leave your model powered and forget about it, I suggest you disconnect the battery and charge it externally with a battery charger before powering up the model again.
I also suggest that you check that the current battery is not damaged and should be replaced.
It was not just a raw lipo cell. This was an opti-guard. A backup power system that engages in case the ESC BEC fails. It has its own protection to shut down before its LIPO gets too discharged. There was no risk of this lipo catching fire. In fact it did shut down when the 450mah pack hit 3.3V/cell. But before it did this it could not maintain the required output voltage and was delivering less than 4.3V to the gyro.
In any case, when the model would not power up, I unplugged the opti gaurd, left the model sitting there unpowered for at least 5 minutes and then plugged in the main flight pack so the gyro was again powered at 8V. It did not power up and took a long time for the red light to come on.
It was also unplugged from power for 12 hours before I plugged it into the USB port which again it took a while before windows detected it.
So I really do not think your explination of corrupt RAM is the issue.
Its probably more likeley that while operating at low voltage the logging system in the Gyro was periodically writting to non-volatile memory and caused corruption.
... So I really do not think your explination of corrupt RAM is the issue.
Its probably more likeley that while operating at low voltage the logging system in the Gyro was periodically writting to non-volatile memory and caused corruption.
It's not like we're going to contradict your beliefs.
If you know better than we do how the unit's firmware works you will also know for sure how the anti-copy routines work and how it is read and checked that the content of the ROM is valid and has not been cloned. You'll also know that the firmware is loaded into the processor's internal ROM while the logs, and events are written to an external memory.
At this point, however, if you already know everything, you should tell us why you wrote to us, explaining what you need to know from us, and how we can help you.
Wow, what a way to talk to your customers. I guess I will never be buying your products again!
If the unit has been purchased within a few days you can request a refund and/or replacement with another brand.
…. There was no risk of this lipo catching fire.
Really sure?
Only some days ago:
https://www.helifreak.com/showthread.php?t=837341