[Elecraft] Li-ion battery pack for KBT2, K2

[Leigh L. Klotz, Jr WA5ZNU]

Johnny,
Some have done this, but the Li+ cells are prone to catch fire, so it's 
risky.  SLA is well understood and less risky.
They can catch fire when over charged, of course, but also when 
over-discharged.

Some people are reporting the A123-manufactured Lithium Nano-Phosphate 
cells are safer than the Li+ and LiPoly.
They don't catch fire when over-discharged, for example. 

Unfortunately, they don't quite fit in the K2 battery case, at least now 
in a way I can figure.  There are also non-A123 brand LiFePO4 cells 
which you should be able to get in HK easily.  These are 3.4v and a 
better fit (4*3.4=13.6, max 14.4v) for 12v radio electronics than the 
~16VDC full charge of Li+.  They are thought to be safer than the Li+ 
cells, but the no-name brands don't necessarily have the same testing as 
A123 brand, so again it's more of a risk than SLA, though less of a risk 
than Li+.

LiFePO4/A123 have excellent power density, and can source 60 amps 
easily, so they must be fused close to the pack.
They don't have as good energy density as the Li+ technology, but with 
the K2 that's less of an issue since its RX draw is so low.

Leigh/WA5ZNU
> Hello Group,
>
> Rechargable Li-ion 3.7v cells are now very cheap ($4 for a 1,500maH cell) and easily available in Hong Kong.   I am thinking to use them to replace the Lead Acid cell of the KBT2.  This will make the K2 less heavy and give more battery power for longer operation time.  K2 will then be more suitable for field day.
>
> Are there any articles in this forum covering this issue before? Or, where can I find the necessary information for such an installation?
>
> Thanks and 73,
>
> Johnny Siu VR2XMC
>
>