Scale Soaring UK

Ok here is a sorry tale. I like to do quite long flights so recently flew my Grunau Baby for nearly an hour. Towards the end I had that horrible feeling we have all had where the model is suddenly not following instructions. To look on the bright side, the crash was on land, not sea so could have been worse. Post crash analysis shows a flat battery do here are the questions:
It was a Panasonic Enyloop 4.8v nmhi. After the crash it showed 4.1v but a mate with a decent battery checker put that on and it showed zero capacity. First question is what is the telemetry on the tx showing? I assumed (ha!) That 5 bars was good 4 ok but I'd have to worry at 1 or 2 bars. I am now wondering if 1 bar = 1 volt? So 5 is good, 4 is disaster? Can I actually get the voltage displayed
Second question is about electricity, my understanding of which is limited. I know v x a = watts which is the power. Analogous to a water pipe, volts is pressure and amps the capacity or charge, so a big wire (pipe) has less resistance and potentially more power. So... if capacity of battery is zero how do I still have 4 volts?
Finally, is it possible to get a battery checker to avoid this again? Any recommendations?? Any advice gladly received.

Nigel,
I doubt those bars mean anything much, but you can show the actual Rx battery voltage very simply and set warnings.

modelgliding@aol.com

get in touch and I can sort you out.

BC

There is a process to calibrate the Taranis / battery telemetry.

https://www.youtube.com/watch?v=JTTqfgbWLPE

mjcp wrote: ↑17 Aug 2021, 13:29 There is a process to calibrate the Taranis / battery telemetry.

https://www.youtube.com/watch?v=JTTqfgbWLPE

That's not too much help, as it is the Tx battery that he is setting, plus he has not measured the voltage under load.



BC

Personally I would not rely on the telemetry to save your model. Start with a good battery supply system. I highly recommend NiMh technology...............
for TV remote controls. I do not recomend them for RC models. They have a high internal resistance and potentially they will let you down when you most need them. I do recommend LiFe and LiIon technologies, as well as using dual batteries. Carrying lead in the nose of your glider? How much current does it supply to your radio? So take out a chunk of church roof and repalce with a second battery!Remember to use diodes between the batteries. Now you have a suitable battery supply system for your model with battery redundancy. There is lots of how to information on this forum. When you have done that, figure out how to get a battery alarm on your Taranis.
John

Nigel sorry to hear of damage to your gorgeous Grunau.
Hopefully it will taste the St Agnes air again soon.
I vote for the Lithium battery suggestion as it seems easier to determine the available capacity remaining and the balancing nose weight may as well work for a living!
Malcolm

The FRSKY rx will work at 3.3v, I went down to 3.9v for ‘one last flight’ today but the servos do get slow which might be what was happening to yours? As I landed the load came off as I stopped using the sticks and popped up to 4.1v .

M