[Elecraft] battery backup, etc. for QRO K2?

[Leigh L. Klotz, Jr.]

I think optimizing for the KBT2 is an unnecessary constraint on your new 
QRO power system.  The charging system for the KBT2 with the resistor is 
an expedient and inexpensive solution, but it isn't optimal itself.

I'd recommend putting a separate connector on as Don suggests, fused 
directly to the battery, and then using your Battery Tender Jr to charge 
it up every now and then.   

The rest of the time, use your regular power; for example, I use a 41AH 
AGM and a Battery Tender (not Jr) for my K2 and 35W HFpacker amp right now.

For 100W SSB, the Gamma Research HPS1a is the tiniest supply you can 
imagine, though reports are you need to go down to 80W for CW.  It's 
small enough to take with you on a trip as well, which isn't something 
you can say about other supplies, even conventional switching supplies.  
(It's smaller than a KX1...)

When my K3 arrives I'll be using the HPS1a at first, but eventually 
upgrading my 40AH AGM battery to something bigger, probably an Optima 
Yellow Top.  I got a 5A solar panel on closeout recently and plan to use 
that to keep it charged during power outages, but use a Battery Tender 
the rest of the time.

Leigh/WA5ZNU