In article ,
John Bartley I solved my XP problems w/ Service Pack Linux wrote:
I'd like to have a 12v battery pack, using throwaway batteries, for
extended field ops with my Yaesu VX-5R HT. I want to be able to
operate without having a genny on hand, and throway cells of a
standardized type allow me to say to Logistics "Uh, go gimme a raft of
them thar D cells", simplifying my life in the process.
Anyone done this with either four pairs of D cells or a pair of 6v
lantern batteries?
Going with 12 volts is probably a waste of money and weight, in this
particular application. My recollection is that the VX-5 only needs
about 8 volts to reach full transmit power (but needs around 9 - 9.5 in
order to be able to charge its internal lithium battery). If you
power it from 12 volts I believe it simply regulates the voltage down
to what it really needs, and this is probably going to result in extra
heat buildup.
You might try 3 pairs of D cells, for around 9 volts nominal - 25%
less weight and I believe you'll probably get good power out. Drop
your transmit power to 1 watt, stick on a spaghetti-noodle antenna
instead of the stock base-loaded rubber duck, and you'll probably at
least triple your battery run-time with no loss of transmit range (and
distinctly-improved receive sensitivity as well). Use a roll-up
J-pole hung up in a tree for even better power conservation.
In a real pinch, use the Yaesu 3-AA-cell battery pack, load it with
alkalines, and you'll still be able to get out 100 milliwatts or so...
enough for some short-range ops.
IIRC, IEC-type D-cells are normally designed to deliver 200mA, whereas
the lantern batteries are designed to deliver 300 mA. Is that correct?
If I recall correctly, this sort of current level is probably what
they're rated for, in terms of mAh. They can deliver a good deal more
current than this, but at the cost of decreased total energy delivery
capability.
--
Dave Platt AE6EO
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