I usually use my K2 with external power from a 12V AGM battery but would
like to be able to charge the KBT2 battery from the same charger I use
for the AGM battery (a Battery Tender 3-stage). I remember reading that
Wayne N6KR put an aux 12V out into one of the spare transverter holes,
and saw Don's note about replacing the diode/resistor with a fuse for to
the KBT2 for use with a multi-stage charger.
I'm thinking of replacing the SPST switch with a DPDT switch and putting
a second coaxial DC power jack in one of the spare transverter holes.
One pole of the DPDT would be used just like the current SPST, to
connect and disconnect the internal battery. The other pole (and its
opposite throw) would connect the battery through a fuse to the second,
charge-only jack without going through the diode and resistor, and
without going to the K2 DC in. This keeps both jacks from seeing power
at the same time, and prevents you from accidently running the rig off
the multi-stage charger jack.
Ideally I'd like an ON-OFF-ON switch, so there would be a middle OFF
position that removes power from the everywhere (including the charging
jack), but I can't find one that fits in the space. I notice that
ITT/Canon makes a DPDT switch V80212SS05Q in the exact same form factor
as their V70113SS05Q SPST part currently used. See [1] Mouser and [2]
DigiKey for the DPDT ON-ON versions.
Has anybody else done something like this, or found an ON-OFF-ON switch
that fits in the KBT2 switch location, or have any better ideas on how
to provide the flexibility of charging either with a 14V wall wart
through the diode/resistor or a multi-stage charger, and still providing
safety?
[1] http://www.mouser.com/catalog/620/1038.pdf
[2] http://dkc3.digikey.com/PDF/T043/1128-1129.pdf
Thanks,
Leigh WA5ZNU
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