slightly OT: need reference for solar charging system for 18AH battery

[Allan Taylor]

I know someone who checks this reflector is heavily involved in solar
charging for small (QRP) station use. I have
a fresh 18 Ah battery that I wish to take along to power the K2 on a
white water raft trip (Salmon River, Middle Fork).
This has proven an impetus to finally inquire about a solar charging
system. Can someone point me to this
person (or others) to get me off dead center??

--
73     Allan    K7GT
______________________________________________________________
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

[Jim Wiley-2]

So, what do you want to know?  
 

To answer your questions, whatever they may be,  some preliminary
information is needed.


How much operating time do you plan on doing each day (what is the duty
cycle)?  


Will you be in any one place long enough to have a solar panel
stationary (for best charging)?


Will you be attempting to charge the batteries (or operate) while in
motion?


Where is the Salmon river (what state)?


Is the river "out in the open" or running down a steep-walled canyon?


Do you have,  or have access to,  a solar battery charge controller?


Do you already have, or have access to,  one or more solar panels, and
if so, what is their rating?


If not, what is your budget to purchase panels?


I am assuming the battery in question is a sealed gel-cell, using
lead-acid chemistry.  Is this correct?  If so, remember that the maximum
charge rate for best battery life is about 3 amperes ( a charge rate no
more than 1/6 of the ampere-hour capacity is the rule of thumb for
gel-cells).  Using that as a benchmark,  it will take approximately 7
hours for a full recharge - the other rule of thumb is that you will
have to "return" about 120% of what you take out to recharge the system.


Is any source of power (other than solar cells) available - for example,
from the charging circuit of the boat (if it has one) or from "shore
power" when you are stationary for an evening?   Are you bringing along
a small generator for lights, entertainment systems,  or food
preservation (a refrigerator)?


How long (in days) is the excursion scheduled to last?


Do you have, or have access to, a small wind turbine generator (to
charge batteries at night)?


What time of year do you plan on doing this (the amount of solar energy
available varies with the seasons)?


Do you plan on using the K2 on CW or SSB, and at what power level?


Be aware that a fully charged 18 Ah battery will  run the K2 for a
significant amount of time with no additional charging. Others on this
list may have more information, but I would expect to get 20 or more
hours of actual operation if you are on the air a lot (contest style
operating), and substantially more hours if you are doing casual
contacts?  20 hours is 4 hours a day for 5 days  quite a long time,
actually, when you consider that most of your daylight hours are likely
to be involved with the actual navigation of the river, and not pulled
out to shore.  If it were my choice, and I were considering a rather
"radio heavy" schedule, I might opt instead for a 2nd fully charged
battery and not worry about recharging until you get back home.  .A
second battery will be substantially less expensive than buying a solar
panel that is capable of any serious amount of recharging in the short
intervals that are likely to be available, and quite possible less
intrusive from a  physical size and "carry weight" point of view as
well.  


Once you have developed the answers to these questions, then it becomes
possible to offer some ideas for your project.


- Jim, KL7CC


  .

Allan Taylor wrote:
> I know someone who checks this reflector is heavily involved in solar
> charging for small (QRP) station use. I have
> a fresh 18 Ah battery that I wish to take along to power the K2 on a
> white water raft trip (Salmon River, Middle Fork).
> This has proven an impetus to finally inquire about a solar charging
> system. Can someone point me to this
> person (or others) to get me off dead center??
>
>  
______________________________________________________________
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

[Brian - K9WIS]

There are several good articles for solar chargers and solar charge controllers in the QST archives that you can access from the ARRL web page. (If your a member)

Brian K9WIS

--- On Thu, 7/9/09, Allan Taylor <[hidden email]> wrote:

> From: Allan Taylor <[hidden email]>
> Subject: [Elecraft] slightly OT: need reference for solar charging system for 18AH battery
> To: "Elecraft" <[hidden email]>
> Date: Thursday, July 9, 2009, 8:43 PM
> I know someone who checks this
> reflector is heavily involved in solar
> charging for small (QRP) station use. I have
> a fresh 18 Ah battery that I wish to take along to power
> the K2 on a
> white water raft trip (Salmon River, Middle Fork).
> This has proven an impetus to finally inquire about a solar
> charging
> system. Can someone point me to this
> person (or others) to get me off dead center??
>
> --
> 73     Allan    K7GT
> ______________________________________________________________
> 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
>

     
______________________________________________________________
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

[Julius Fazekas n2wn]

Hi Allan,

There are several options. Check the QST archives for some of them.

This kit, from an article in QST, is pretty popular:
http://www.theheathkitshop.com/page24/page24.html

Also check an article bt AA4PB entitled "An Automatic Sealed-Lead-Acid Battery Charger" from 2001.

If you're using the internal KBAT2, you should only need a simple blocking diode circuit from the panel (that's making several assumptions on my part) to keep it charged.

Someone on here, a 5lander, also had a kit for solar panels a few years back.

Happy rafting!

73,
Julius

Allan Taylor wrote

I know someone who checks this reflector is heavily involved in solar
charging for small (QRP) station use. I have
a fresh 18 Ah battery that I wish to take along to power the K2 on a
white water raft trip (Salmon River, Middle Fork).
This has proven an impetus to finally inquire about a solar charging
system. Can someone point me to this
person (or others) to get me off dead center??

--
73     Allan    K7GT
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[e-mail]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html