[Elecraft] [KX3] Boost Buck 13.8 V Regulator

[Dr. Werner Furlan]

Mark, 

this is exactly what I do. The LiFePO4 has a little more weight, but the cells are robust 
and have the correct voltage and probably can do more charge/discharge cycles. 
I think the trouble with a voltage regulator is not worth the very little gain in weight. 
Regarding the Eneloops in the KX3 I do not know if they take over the supply if the external 
power supply drops under 10V, but usually there is a switch in the plug which switches off the 
internal battery. I'll have to check this out. 

73! de Werner OE9FWV


On 13 May 2013 at 5:55, Mark Goldberg wrote:

> How about using a 4S LiFePO4 battery? From fully charged to 15% charge
> I get from about 14 V to 12 V in RX and very little sag on transmit.
> Pretty much the ideal battery for this radio in my opinion. They are
> rated to go down to 10V or so, but since you don't get that much more
> and you can permanently damage the batteries if you go too low, I stop
> at 12V. The KX3 will run full power throughout this range, too. I use
> real A123 brand cells with a balancing charger. These do not have
> quite as much energy density as LiPo;, but you do not need anything
> else. I also keep Eneloops in the KX3. I have not tested it but I
> think it will switch over if the external battery goes below their
> voltage, somewhere about 10 V. If someone could confirm that, it would
> be great. Those NIMH Eneloops run below 11V for most of the discharge
> cycle, so only 5 W on those but they hold a charge a long time so they
> can be used in a pinch.
> 
> 73
> 
> Mark
> 
> 


-- 
Es ist schwieriger, eine vorgefasste Meinung zu zertr³mmern, als ein Atom.
 Albert Einstein (1879 - 1955), Physiker


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