[Elecraft] RE: Secondary Power Connector Suggestion, etc.

[John Clifford]

I wanted to do the same thing for my K2, because I also wanted to be able to
hook up a solar panel/charge controller/spare batteries.

You do not want to run a charge controller thru your main power jack... the
polarity protection diode will prevent the charger from monitoring the
battery's charge level and thus it will never turn off and will overcharge
your battery and kill it.  The idea of adding an electrical 'T-fitting'
between the main power supply and your solar controller is also not a good
one, for many reasons (you may harm your power supply if it is off and the
solar controller is powered, other devices on the same buss may not like the
varying voltages and on/off cycles produced by a PWM charge controller,
etc.).

I went ahead and added a separate 'battery' power jack with identical specs
to the main Elecraft power jack to one of the transverter holes (I figure
that if I do use a transverter with the K2, I'll use an external one such as
a Ten-Tec that will be accessed thru one of the antenna connectors).  I
haven't fused it... but I will go back and do that this weekend!  I
recommend that you fuse your connection so if a short occurs you won't ruin
your K2 when the internal battery explodes/melts.

Since I already purchased an Alinco DM-330MV 35a power supply for my Omni VI
and KPA100, I use my RS 3a power supply (modified to 14.5v) as a battery
charging power supply.  I hook it up thru my charge controller to the
battery power jack every couple of months if I haven't used the battery, and
it takes maybe 15 minutes to 'top it off'.

I can also use the same setup to charge several 12v/7AH cells I have (for
spare power and I also use them with a booklight I have for reading in bed
at night), and to charge two 12v/40AH gel cells I purchased as backup power
for my shack.

The reverse polarity protection diode that is inline in the main K2 power
jack prevents charging current from traveling back up to my DM-330MV so I
don't have to worry about hurting it.

I will eventually have two power busses in my shack... one powered by the
DM-330MV thru my MFJ 1116 DC power strip that is my primary power source for
my equipment, and one off of a second 'battery buss' that will have the two
40AH gel cells on it, charged, as well as the K2's battery and my other 12v
stuff that I don't want powered down when the main supply is turned off (my
R8A, Libretto CT100, etc.).  I will use a cheap lamp timer to turn the RS
charger on every night for an hour or so to keep things topped off.  I will
also have a cable made up with a diode that runs the 12v to the main buss in
order to allow for battery backup in case the power goes down while I am
operating.  I eventually plan to install a solar panel that will replace the
RS 3A supply as the charging source for the battery buss.

I am debating dropping the 'banana plug' connector convention required by
the MFJ strip and converting completely to Anderson PowerPoles... yet
another good idea that will require more money!  BTW, has anyone toyed
with/actually converted the K2 from its current axial power connector to a
Powerpole connector (by actually replacing the PCB jack with a PowerPole
jack and modifying the back of the case accordingly)?  I know the KPA100 has
a PowerPole jack, and the K2 will be powered from that source if the KPA100
is installed... but what do you think about replacing the connector on the
K2 itself?

 - jgc

John Clifford KD7KGX

Heathkit HW-9 WARC/HFT-9/HM-9
Elecraft K2 #1678 /KSB2/KIO2/KBT2/KAT2/KNB2/KAF2
                  ...waiting _eagerly_ for KPA2!
Ten-Tec Omni VI/Opt1

email: kd7kgx@arrl.net