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KX3 and Solar Panel

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Lee Stephens

KX3 and Solar Panel

Ok....so while at Dayton I purchased a 20W foldable solar panel with
an Anderson Power Pole connector. Today was the first day I got to
test it out at the park and as advertised it needed absolutely no time
to start sending electrons to the radio....no warm up time needed.
The operating voltage is advertised at 15.4 volts. When I powered on
the KX3 it was on 10 seconds or so and gave me a warning that the
input was >16 volts and the KX3 then shut down to protect itself.
Ok...so it has 4 rows of panels....I folded one under and bam....it
gave me a >16 vots of input and shut down again....so I covered up
another row and it wouldn't come on....I covered up one of the squares
and had a nice 13 volts input and it operated fine. Sending at 10
watts and the reports on the other end on 17 meters were, "You sound
like you always do"...which locally means good...but still lost in the
dog piles of a DX.

So...this thing is putting out more power than it is supposed
to...which is a good surprise...and watching the KX3 screen the
voltage seemed stable throughout SSB at 10 watts...I'd like to test
that out on JT65 but I left the laptop at home and I didn't have any
memories set for a long CQ on RTTY and didn't have the CW key either
for input.

So, anyone have a suggestion on an inline voltage regulator...say just
Anderson Power Poles on both ends and a potentiometer to let me dial
down to the desired input voltage? It would be nice to have a digital
screen but not necessary since I should be able to read the voltages
on the KX3 screen. The lighter the weight the better. The whole
point of the light weight fold-able solar panel was for back packing
to a summit and staying there for a while and leaving the batteries
behind.

Thanks for any help and suggestions

Lee Stephens
KK4JSJ
KX3 #3462

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Lee Stephens

Re: KX3 and Solar Panel

Thanks John,

That satisfies my need on several levels.

1. I can set the output voltage and then lock the set screw so it
doesn't move if bumped.
2. It weighs 1.6 ounces
3. I can make up whatever length leads I want with APP connectors
4. The output voltage isn't going to waver unless the input voltage
drops below the desired output...say clouds roll up and it goes from
16 vdc to 13 vdc and I have it to ~13 vdc.
5. They are in Akron, OH and the shipping time to Northern Kentucky
wouldn't be very long and they say they are in stock.

Again, Thanks John,

73,

Lee Stephens
KK4JSJ
KX3 #3462

On Monday 05/27/2013 at 6:34 pm, Dr John H Farmer wrote:

>
>
> Hi Lee,
>
> The open circuit voltage on these panels is often higher than is
> acceptable to the radio's input regulator.
>
> I use one of these:
>
> http://www.dimensionengineering.com/products/anyvolt3
>
>
> They're tiny and weigh nothing. I have leads with APP connections
> attached to it.
>
>
> 73,
>
>
> John
> VK7JB

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Barry K3NDM

Re: KX3 and Solar Panel

In reply to this post by Lee Stephens

Lee,
I think I'd use a small, ~8Ah. The solar panel will charge the battery, and the battery will keep the voltage closer to what you need. The best part is that you'll be able to operate after dark.

73,
Barry
K3NDM

----- Original Message -----
From: "Lee Stephens" <[hidden email]>
To: [hidden email]
Sent: Monday, May 27, 2013 6:26:37 PM
Subject: [Elecraft] KX3 and Solar Panel

Ok....so while at Dayton I purchased a 20W foldable solar panel with
an Anderson Power Pole connector. Today was the first day I got to
test it out at the park and as advertised it needed absolutely no time
to start sending electrons to the radio....no warm up time needed.
The operating voltage is advertised at 15.4 volts. When I powered on
the KX3 it was on 10 seconds or so and gave me a warning that the
input was >16 volts and the KX3 then shut down to protect itself.
Ok...so it has 4 rows of panels....I folded one under and bam....it
gave me a >16 vots of input and shut down again....so I covered up
another row and it wouldn't come on....I covered up one of the squares
and had a nice 13 volts input and it operated fine. Sending at 10
watts and the reports on the other end on 17 meters were, "You sound
like you always do"...which locally means good...but still lost in the
dog piles of a DX.

So...this thing is putting out more power than it is supposed
to...which is a good surprise...and watching the KX3 screen the
voltage seemed stable throughout SSB at 10 watts...I'd like to test
that out on JT65 but I left the laptop at home and I didn't have any
memories set for a long CQ on RTTY and didn't have the CW key either
for input.

So, anyone have a suggestion on an inline voltage regulator...say just
Anderson Power Poles on both ends and a potentiometer to let me dial
down to the desired input voltage? It would be nice to have a digital
screen but not necessary since I should be able to read the voltages
on the KX3 screen. The lighter the weight the better. The whole
point of the light weight fold-able solar panel was for back packing
to a summit and staying there for a while and leaving the batteries
behind.

Thanks for any help and suggestions

Lee Stephens
KK4JSJ
KX3 #3462

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Greg Troxel

Re: KX3 and Solar Panel

In reply to this post by Lee Stephens

A 20W panel that is labeled as for a "12V" system will typically have a
Voc (open circuit) of 22ish V, and a Vmp (maximum power voltage) of 18V.

Generally, one should not hook up a bare panel to a load, and the usual
recommendation is charge controller and battery. I wonder about a
large cap instead of a battery, enough to make the controller stable.

I have a 20W (HQRP) panel and use a Genasun GV-5 MPPT charge controller and
then charge about 100Ah of batteries. I have not tried the controller
with no batteries.

The anyvolt3 is an interesting concept for this application. MPPT
controllers try different voltage/current combinations to find the one
that's in-range for the DC-DC converter and results in maximal power.
I have found that to be around 17.5-18V whenever I get more than 200 mA
From the system (sometimes I see 1.6A). The anyvolt3 is expecting a
voltage source, it seems, and the datasheet seems to imply that. A
panel is not a voltage source. So I really wonder what would happen.
Has anyone put a high-speed scope on the input when hooked up to a
panel?
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Millerhill

Re: KX3 and Solar Panel

In reply to this post by Lee Stephens

Check this out.

I got one and it works great.

http://acmeqrp.com

73
Steve
W1SFR

On May 27, 2013, at 6:50 PM, Lee Stephens wrote:

>
> Thanks John,
>
> That satisfies my need on several levels.
>
> 1. I can set the output voltage and then lock the set screw so it doesn't move if bumped.
> 2. It weighs 1.6 ounces
> 3. I can make up whatever length leads I want with APP connectors
> 4. The output voltage isn't going to waver unless the input voltage drops below the desired output...say clouds roll up and it goes from 16 vdc to 13 vdc and I have it to ~13 vdc.
> 5. They are in Akron, OH and the shipping time to Northern Kentucky wouldn't be very long and they say they are in stock.
>
> Again, Thanks John,
>
> 73,
>
> Lee Stephens
> KK4JSJ
> KX3 #3462
>
>
>
> On Monday 05/27/2013 at 6:34 pm, Dr John H Farmer wrote:
>>
>>
>> Hi Lee,
>>
>> The open circuit voltage on these panels is often higher than is acceptable to the radio's input regulator.
>>
>> I use one of these:
>>
>> http://www.dimensionengineering.com/products/anyvolt3
>>
>>
>> They're tiny and weigh nothing. I have leads with APP connections attached to it.
>>
>>
>> 73,
>>
>>
>> John
>> VK7JB
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html