[Elecraft] Help for K3 Battery Operation

[John]

Sir,

Having had an opportunity to operate my K3 on battery several Field Days ago
I made the following discoveries:

1)      Unless there have been changes made to the K3 line, the transceiver
turns itself off when the supply voltage drops below a nominal 11.5 VDC.

Now you may think this is a rare occurrence; in reality, with any battery,
voltage dips occur due to hefty current surges (typically 20 Amps) on SSB.
I used/and still use a 110 AHr GMS Deep Cycle battery.

The resultant voltage drops were a complete disaster

2)      There is a solution which I now use for K3 operation on battery.  TE
Systems sells voltage boosters which will maintain a constant 13.6 VDC
regardless of the transceiver's current draw.

However, the battery should be fully charged to start and I use a 75 watt
solar panel in parallel with the battery to mitigate current surges during
daylight operation.

3)      Night operation using the TE device is limited to battery voltage
which should not be allow to go below 10.5 VDC else you'll ruin the battery.
TE sElls a meter bridge measuring both input (battery) and output (device)
voltages for their units to facilitate night time ops.

Lots of luck,

73,

John Kountz, WO1S/6, T6EE