Yaesu: Yaesu old NiCd Battery Packs FNB- circuits

Edelweiss

Author of: Scanning the UK Airbands with the Beast
Joined
Jun 8, 2019
Messages
137
Location
England
Hi, has anybody here knowledge about the circuits for FNB-31/ 33, 35 or 8 or FNB-4X series battery packs?
I am sure there is nothing too special in there just wondering what the BAT SEL on the radio really does
Is it is an internal thermistor to prevent overcharge with the external charger? Some battery packs also seem to feature fuses etc.

Some battery packs seem to have three pins, others four so it must be for external charge sensing or so, but e.g. BAT SEL on the 3X series is routed inside the hand held radio and must be evaluated there.
Thanks

Mike
 
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