Fox flasher MkII – high power 2 LED solar powered beacon – update 6/2019

Fox flasher MkII – high power 2 LED solar powered beacon described a LED driver for an animal deterrent using a Chinese 8051 architecture microcontroller, the STC15F104E.

FF100This article documents its failure  in June 2019 after five years service. 

With the passage of time, the new PV array surface has degraded but on test, the PV array short circuit current is 90% of rating so it will be retained for a while yet. There is no doubt that inexpensive Chinese PV arrays do not survive direct exposure to weather, and it is doubtful that paying more money buys quality… Chinese Quality is a bit of an oxymoron.

The original 1000mAh 1S LiPo battery has failed almost 2000 shallow discharge / charge cycles, now giving less than 200mAh capacity so it will be replaced. Cell resistance @ 1kHz was 140mΩ, way too high (expected up to perhaps 50mΩ).

Above, a new protected battery was made from a 2500mAh LiIon cell and a 1S protection board and tails with JST RCY connector. This Turnigy cell cost around $5 as test showed is delivered its rated capacity.

The battery was served with heatshrink sleeve.

More damage to the ABS jiffy box as a result of ice expansion was repaired by plastic welding the affected screw well on the cover. These are clearly not a good option in climates where rain or condensation may freeze.