Curious Cow

I got my Mavic Air up this afternoon, between showers.  I had intended to capture the lowering clouds and moody light, but this Highland cow caught my eye.  She lives and eats in the field next to our house so was quite close to my when I noticed that she was peering up at the sky, presumably interested in the buzzing of the drone.  It was quite a sweet attitude, and I know that you can't really see her craning her neck to see upwards, but she was.

I was also interested to see that the Li-on battery in my drone had not depleted over about five days.  It's an "intelligent" battery which "knows" that it should not hold a full charge for very long and has what seems to be a planned drain of that charge; but it was at almost 100%.

Lithium batteries are interesting, as I learned when I was teaching the use of night vision goggles at the Centre of Aviation Medicine (RAF).  Many NVGs use lithium batteries because they hold their charge for a long time and don't reduce their output in use until they suddenly drop off – important for the reliability of NVGs. But they are prone to burst into flames, if abused, and the anode develops a thin film ("sublimation") which seems to reduce any tendency for the battery to lose charge when stored.  But this means that the device using the battery will not work immediately when power is switched on – it can take several seconds to start working.