[Elecraft] Fwd: Re: KX3 power supply "brick"
Dominic Baines
dominic.baines at ntlworld.com
Wed Feb 11 14:03:50 EST 2015
Sent again....
On 11/02/15 08:24, Dominic Baines wrote:
> Lynn,
>
> When travelling I often use a power brick with my KX3. When mains is
> available it is a convenient way to power one. There are quite a few
> to choose from and I did test the voltage output. The near 12V one's
> often vary in output voltage from about 11.8V right up to 14V, mine
> will deliver 14.4V @3 amps no problem. I think it was from some bit of
> portable test kit, rally purchase, but some of the Dell, Acer and HP
> mini laptops used voltages about this level I believe. The other
> alternatives that are relatively easy to obtain are 12V DC lighting
> supplies or CCTV camera supplies. Needless to say they are switch mode
> so can be regarded as the devil spawn by some... but a simple common
> mode choke on the mains in and the DC out usually gets rid of most
> issues (not seen any myself). I added a big 6amp silicon diode (and a
> fuse) in line so it dropped the output voltage to 13.8V nicely). KX3
> reports 13.7V. Nice thing is it 'looks' like a laptop power supply so
> airport security et al are less bothered than something homebrew in an
> ABS/ dicast/Hammond box. Usefully the one I have also has a 5V USB
> output for recharging a mobile phone, ipod etc. It also doubles up as
> the power supply for my acer one laptop.
>
> They tend to be plastic glued/welded shut so you cannot do much about
> what is inside but if you are brave you could rehouse and try and work
> out lifting the output voltage, or trimming it back if too high. A
> lack of any circuit diagram or knowledge about these things and lethal
> main voltages being present precludes me from recommending that course
> of action.
>
> I do not have the battery recharger in either of mine and tend to run
> without internal batteries anyway but you will need >13.8V to get that
> to work, but you could also use a separate 12V to 8AA recharger too I
> believe.
>
> 72
>
> Dom
> M1KTA
> #1082 and #2334
>
> On 10/02/15 22:57, Lynn W. Taylor, WB6UUT wrote:
>> I don't disagree with any of the theory.
>>
>> I was hoping for some responses based on actual experience.
>>
>> -------- Forwarded Message --------
>> Subject: Re: [Elecraft] KX3 power supply "brick"
>> Date: Tue, 10 Feb 2015 17:10:55 -0500
>> From: Nr4c <nr4c at widomaker.com>
>> To: Lynn W. Taylor, WB6UUT <KX3 at ColdRocksHotBrooms.com>
>>
>>
>>
>> You'll need at least 13.8 volts to charge the batteries.
>>
>> Sent from my iPhone
>> ...nr4c. bill
>>
>>
>>> On Feb 10, 2015, at 3:57 PM, Lynn W. Taylor, WB6UUT
>>> <KX3 at ColdRocksHotBrooms.com> wrote:
>>>
>>> I just looked at four bricks floating around my office, and two of
>>> them are 12v. The other two are 18v and 19v.
>>>
>>> The smallest one I have is 2a, which would probably charge the
>>> internal KX3 batteries. The bigger one might be okay for transmitting.
>>>
>>> That's why I specified "12v brick" in my post. There are many
>>> different bricks out there.
>>>
>>> 73 -- Lynn
>>>
>>>> On 2/10/2015 12:34 PM, Walter Underwood wrote:
>>>> Most laptop bricks are 16V or higher, too much voltage for the KX3.
>>>>
>>>> wunder
>>>> K6WRU
>>>> CM87wj
>>>> http://observer.wunderwood.org/
>>>>
>>>>
>>>
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>>
>>
>>
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