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
---
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