[Elecraft] [K2] LiFePO4 replacement for internal SLA battery in K2

[Bill W4ZV]

inventor61 . wrote
> I had strongly considered the LiPo type secondary-cell power packaging
> option and rejected it.
> 
> Energy density in that chemistry/package is amazing of course.  But that
> equation is also true of a bomb.  I have no problem with the LiPo in my
> iPad, Galaxy S5 phone, and laptop, so, it's not a blind bias.
> 
> It doesn't take too much YouTube searching to find dramatic examples of
> LiPo powered RC vehicles and the like bursting into flames.
> 
> There's a good reason that *all* these lithium cells are considered hazmat
> now, not just the lithium thionyl chloride ones ... on failure, those burn
> and emit nerve gas; they are Class 9 hazmat!  They are also not
> rechargeable anyway.
> 
> Because this particular power pack would be fully enclosed in the
> metal-cased K2, and would be in the 9 ampere-hour range in this desired
> form factor ... if such a LiPo pack decided to self-immolate, the rig
> would
> not only be destroyed but I'd have a real secondary incendiary hazard on
> my
> hands.
> 
> The charging, power regulation and protective circuitry, etc., needed to
> use the LiPo chemistry/packaging inside a K2 took that consideration off
> the table for me.  YMMV.

I understand and agree for your use case of mounting the battery internally
in the K2.  My "fail safe" is to never use an internal battery and thus
avoid issues of fire, leakage, etc.  I always charge and mount my LiPOs
externally.  It's certainly possible to abuse LiPOs and cause them to catch
on fire, but as you stated, there are plenty of devices that successfully
use them internally...significantly more than LiFePO4s when you consider the
volumes of cell phones, tablets, PCs, models, drones, etc. that use LiPOs.

Just an FYI for anyone interested, the "11.1V 4500mAh 3S 30C Lipo" listed on
a popular auction site for $24.36 is actually available for $20 if you use
"Make Offer" (I just bought one).  Of course you also need a balancing
charger (available for around $20) to properly charge and store LiPOs.  You
cannot beat the energy density (mAH per ounce) of a LiPO but they DO REQUIRE
proper care.

73,  Bill  W4ZV





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