[Elecraft] KBT3?

[Leigh L. Klotz, Jr WA5ZNU]

The LiFePo4 packs that are showing up on the market these days are more 
than adequate for running the K3 and its KPA3 at 100W.
Although the connections to the supply might be more easily done in the 
space occupied by the KPA3, the use case is much better for a K3+KPA3 
with a LiFePO4 pack.  Perhaps a bracket that is used in place of the 
KRX3 would be more useful, if perhaps more engineering work.

The 0.9A draw of the K3 in RX would deplete a 2.4AH LiFePO4 pack in a 
couple of hours of just RX, and the TX current draw of the QRP K3 
doesn't require the power density of LiFePO4 either.  So, a QRP K3 would 
do better with a more energy dense pack.  But the KPA3 does need the 
high power density provided by LiFePO4 packs.

There's also the safety issue: Li+  and LiPoly packs are much less safe 
than LiFePO4, and I suspect that if they're widely used in ham gear, 
some day there will be a catastrophic rig accident.  The LiFePO4 
chemistry is much safer, especially with regard to over- and 
under-charging and physical damage.

Leigh/WA5ZNU

Wayne N6KR wrote:
> ...OTOH, we could offer an internal Li-ion battery for the K3 that 
> would be interchangeable with the KPA3 module. We could get about 7 AH 
> in there, I bet. Built-in fast charger, charge monitoring at the front 
> panel, separate fuse.... hmmmm.... nice for QRP picnic-table outings.
>
> A fuel cell would be even more fun.
>
> 73,
> Wayne
> N6KR
>
> ---