[Elecraft] KX3/P3 external power source

[Fred Jensen]

LiPoly or LiFePO4 are both good, the LiFe seems to be a somewhat more 
stable and forgiving chemistry.  I use a4S1P LiFePO4 with my K2.  It has 
a very flat discharge curveuntil the end and then it drops rapidly, the 
K2 shuts down and the battery is protected from complete discharge.  I 
can get about 93% of the energy before the K2 shuts down.  You really 
want a cell balancing charger, but it sounds like you may already have one.

LiPoly's are lighter of course, but I had one catch fire while I was on 
my KX1 so I'm a bit wary of them.  The LiFe is not that much heavier.

Beware of "hot deals" on Li batteries. I bought an allegedly 9 Ah Li-ion 
batterywhich came from you know where.  It had a linear discharge curve 
with a slope of about 1 and the K2 shut down after I'd used around 1.4 
Ah of the stored energy. All the rest was inaccessible by my K2.

73,

Fred ("Skip") K6DGW
Sparks NV USA
Washoe County DM09dn

On 6/7/2017 10:29 AM, Matthew MacRoberts wrote:
> I need to work up a reliable external power source for my KX3 and P3. I also have RC aircraft and cars… So a LiPo or LiFe battery is an easy solution for me.
>
> The battery would offer substantial weight savings and I already have the chargers and other equipment necessary to build the connections.
>
> Is there anything that I need to be aware of? Would a 4S 14.8V 5200mAh 50C be workable?
>
> What other advice would you have?
>