Hi there, my goggles shuts down at 7.8v what could be the issue?

Have you tried a different battery.

Nope, not yet. Could it be the battery?

The minimum voltage that the HDO2's are specified as requiring is 7V, but the likelihood is that they won't run all the way down to that voltage before shutting off, and there is probably an element of miscalibration with the volt meter in the goggles. So when the volt meter is showing 7.8V, the real voltage might actually be lower than that. The audible low battery alarm on the HDO2's is configured to sound when the voltage drops below 8.8V, so that should give you plenty of warning to swap over the battery ASAP. I would recommend using a 3S battery on the FatShark HDO2 goggles rather than a 2S battery to avoid getting into a low voltage situation.

I‘ve tested the liion with the multimeter.
But question: 2s max voltage is 8.4v or am i wrong!? So why are thy puting an alarm at 8.8v ?
Will try a 3s lipo instead.
Thx ?

Sorry, that 8.8V was a mistake. I clearly need some glasses. The audible alarm goes off at 6.8V, but that makes no sense with the minimum input voltage specification for the FatShark HDO2 goggles being 7V. Maybe it can run lower than 7V but if that was the case then I'm not sure why the manual would explicitly state 7V as the minimum input voltage.

If you have a variable voltage PSU which is calibrated then the easiest way to find out is to set it to 8.4V and hook it up to the goggles. Then slowly dial the voltage down until the audible low voltage alarm on the goggles goes off, and then lower still until the goggles eventually power off. You will then know at what voltage readings in the goggles those two threshold values actually are in real life.

I have a pair of FatShark HDO (V1) goggles which have the same input voltage range and audible voltage warning value as the HDO2 goggles. If you want me to do the PSU test on them that I mentioned in the previous paragraph then just let me know and I will gladly do that.

Thx for the help, i have to get an psu… what kind would you suggest?

I just tested the voltage warning beeper and power off voltages on my FatShark HDO (V1's) using a PSU where I slowly wound down the output voltage on it:

• At 7V the warning beeper starts sounding.
  
• At 5.7V the screens power off completely and go black.
  
• I am unable to power the screens back on unless the voltage is set to at least 6V.
  

I would expect the beeper warning and power off voltages to be the same or very similar on the FatShark HDO2 goggles, but there is no way of really knowing unless you or someone else were to perform the same tests on a pair of those.

A number of people in the FPV community seem to use the ToolkitRC P200 Mini Desktop Power Supply which costs just under 100 Euros. I've never used one of those so I can't give any personal opinions as to how good it actually is. I use a YIHUA 3005D PSU as per shown in one of my photos below.

I just don’t get it… ?‍♂️ yesterday the psu arrived and i tested everything:
At 7.2v it starts beeping and at 5v the fan stops ? but the goggles never shut down completely with the psu.

Now i tried to change batteries, tried the batts from my dji v2, works perfectly fine for about 20min and it shuts down randomly, after restarting i get another 10min or so.

Checked the battery v 8.12…

No idea whats wrong.

Changed the cable and tried two different „male“ plugs on the goggles.

Quite frustrating ?

Run a second 2S pack in parallel and see if the time increases. Could be something overheating or maybe a component is slowly dying.

Well just made an 3s lipo from a sagging 4s. Will try tomorrow on 3s…

(26-Nov-2023, 11:32 PM)Pathfinder075 Wrote: Run a second 2S pack in parallel and see if the time increases. Could be something overheating or maybe a component is slowly dying.

If that would be the case, new goggles? :/ or do fatshark repairs them for an accurate money?

According to Snow, Fatshark seem to have a "tough shit" type of attitude to after sales repairs and replacements. So YMMV.

I honestly don't know beyond that. But yes, it could be time for new goggles, or you need to work out some way of keeping the voltage above 7.8V by paralleling loads of batteries or using say 18650 or 21700 packs in parallel to achieve the same.

Right now they haven't failed, so you might still get some mileage out of them, but how long is anyone's guess.

My Fatshark HDO2's came with a li-ion battery holder and I am using 2 Panasonic NCR18650B 3400mAh batteries. I put them on the charger when I get to about 25% charge left. I have never run them down to where any beeping starts so I can't comment on that.

Your shut off are too random. I wonder if there is issue with your barrel connector. Maybe a cold solder or something similar. It might be very repairable.