PoE hat from pi-supply.com died – again

The previous repair lasted for almost 9 month. Today the Power over Ethernet (PoE) hat from pi-supply.com that is powering my ADSB receiver died again when a thunderstorm was passing overhead. Like last time, no direct lightning but according to weather monitoring we got several >150kA flashes within 3km distance. As a result, again, the DC-DC converter Silvertel AG9805-M on PoE ceased to work. This time no short on the inputs, but no output voltage. Even having some more spares add hand I decided to replace this converter by a TDK CCG15-48-05S. This one has a higher input voltage tolerance, up to 75V and hopefully a better surge protection. Let’s see how long this last.


Rohde&Schwarz FSH6 modified for Li-Io battery

Finally I modified my Rohde&Schwarz FSH6 spectrum analyzer to run from a Li-Io battery instead NiMH. Dying batteries are an annoying problem of the old R&S FSH3/6 series by design. The device has no real power switch but goes in standby on power off. Drawing a standby current of about 1.2mA in combination with the memory and self-discharge effect in NiMH batteries let them die sooner or later.

To solve that I decided to install a Li-Io battery with protection board. Apart from a better Li-Io life cycle these batteries double the capacity with a lower cell count. Original 6S1P 3200mAh NiMH replaced by 2S2P 7000mAh Li-Io type 18650 cells. 2S2P means two cells in parallel with another two cells in series.

Li-Io battery pack installed in FSH6. Connected by original wiring.

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