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Help! What's wrong with my 12v Solar Charger?

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tonedef

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Oct 5, 2008, 8:21:25 PM10/5/08
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I'm trying to put together a solar charger by connecting a 12v, 1A PV
panel to a female car power supply. The soldering is all correct, and
with the correct polarity. My multimeter reads +12v at the female
power outlet, but when I plug things in, no charging occurs. What
could be going on here? Thank you for any insight. :) Could I provide
any more info to help out?

Mauried

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Oct 6, 2008, 2:09:55 AM10/6/08
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On Sun, 5 Oct 2008 17:21:25 -0700 (PDT), tonedef <asar...@gmail.com>
wrote:

Car batteries need around 13 - 14 volts to charge them.
A 12V solar panel wont do much at all.

tonedef

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Oct 6, 2008, 12:12:18 PM10/6/08
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On Oct 6, 2:09 am, maur...@tpg.com.au (Mauried) wrote:
> On Sun, 5 Oct 2008 17:21:25 -0700 (PDT), tonedef <asark...@gmail.com>

In full sunlight, the charger does supply 14v, but I'm not using it to
charge a car battery; I want to use it to charge portable electronic
devices that use car adapters.

Eeyore

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Oct 7, 2008, 6:32:27 AM10/7/08
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tonedef wrote:

Simple. You need more than 12V to charge a 12V battery.

Graham


Eeyore

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Oct 7, 2008, 6:34:12 AM10/7/08
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Mauried wrote:

The 'resting voltage' of a 12V battery should actually be around 12.6V.

His solar panel could conceivably be DISCHARGING the battery .

Graham


Eeyore

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Oct 7, 2008, 6:35:08 AM10/7/08
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tonedef wrote:

You're need to learn some more. Stuff like this is not for DIYers.

Graham


sno

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Oct 7, 2008, 7:34:03 AM10/7/08
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Rather than trying to reinvent the wheel...here is a link to some
inexpensive chargers....

http://www.treehugger.com/files/2006/01/get_free_power.php

hope helps..have fun.....sno

Russ in San Diego

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Oct 7, 2008, 10:34:45 AM10/7/08
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On Oct 7, 3:35 am, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:

> You're need to learn some more. Stuff like this is not for DIYers.
>
> Graham

Why the heck would you want to discourage someone from learning things
for themselves??? You do NOT need to have a college degree to work
with this stuff. You DO need to learn more electrical and electronics
theory, though.

Tonedef, if your goal is simply to charge a few devices with a solar
panel, then you would probably be better off purchasing one.

If your goal is to learn something about electronics and using solar
power, then by all means, go ahead. Apparently, you shouldn't expect
much encouragement here, though. Go start googling for information on
building a solar charger. Go to the library and get some books out on
basic electronics and electrical theory.

The problem is probably that your devices are drawing more power than
your panel generates. What is the rating of your panel in watts, and
how much power do your devices draw? In general, you're better off
running a panel into a battery, and then connecting your appliance
chargers to the battery. The battery can accumulate a charge and can
dispense higher power levels (but only for a short time). In other
words, your charger can accumulate, say for 5 hours at 5 watts,
yielding 25 watt hours. It can then dispense at 10 watts for 2.5
hours (less, actually, since there are losses in the battery). You
would also want to eventually add a charger circuit to your project,
to avoid overcharging the battery.

It's not rocket science, but you do need to do some research and
experimentation.

Gordon

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Oct 7, 2008, 6:18:12 PM10/7/08
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tonedef <asar...@gmail.com> wrote in news:132a0866-33bc-4f8b-a855-
dbcce7...@q5g2000hsa.googlegroups.com:

What kind of voltage reading do you get with somthing plugged
in? It is possible that you are trying to draw too much
from the panal.

yoyo

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Oct 7, 2008, 10:31:37 PM10/7/08
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On Mon, 06 Oct 2008 09:12:18 -0700, tonedef wrote:
> In full sunlight, the charger does supply 14v, but I'm not using it to
> charge a car battery; I want to use it to charge portable electronic
> devices that use car adapters.

Do you have any other specs on the panel such as wattage or current? How
about the dimensions of the panel in order to guess its power?

What is the wattage/amps draw of the devices you are charging?

--
/home/gelmjw/sigs.txt

Eeyore

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Oct 8, 2008, 4:43:03 AM10/8/08
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Russ in San Diego wrote:

> Eeyore wrote:
>
> > You're need to learn some more. Stuff like this is not for DIYers.
> >
> > Graham
>
> Why the heck would you want to discourage someone from learning things
> for themselves???

READ MY LIPS (or words)

"You're (going to) need to learn some more" - [correction added]

I believe the word LEARN was in there.

Now what's YOUR problem ?

Graham

Eeyore

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Oct 8, 2008, 4:44:48 AM10/8/08
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Russ in San Diego wrote:

> Apparently, you shouldn't expect much encouragement here, though.

Eh ? I did a 100% worked example.

And NO I WON'T encourage people to use PV solar for inappropriate tasks.

Graham

spaco

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Oct 12, 2008, 7:00:03 PM10/12/08
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Since you make the point that your "soldering is correct", I'll assume
that you are new to electronic stuff.
First: Are you reading the 12 volts with an analog multimeter or a
digital multimeter? An analog meter may not be sensitive enough to tell
you whether you are getting 12.0 volts or 12.5 volts.
You will need something like at least 12.7 volts to send current
into a car battery.
Second: I assume that you are reading the +12 volts at the center
terminal of the socket with the red multimeter lead. This should be
correct for most negative ground cars.
Are you reading the 12 volts with the battery connected? If so,
disconnect the battery and read the "raw" voltage right from the solar
panel. If it is a panel designed to CHARGE a 12 volts battery, then its
open circuit voltage, in BRIGHT SUN should be at least 15 or 15 volts
and maybe as much as 20 volts. If this is NOT the case, then you have
the wrong solar panel for the job.

How do you know that no charging is occurring? It could be that the
battery is already fully discharged or defective and that your small
panel's output is only slowly doing anything.


Pete Stanaitis
------------------------------------

Eeyore

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Oct 14, 2008, 7:23:10 PM10/14/08
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spaco wrote:

> Since you make the point that your "soldering is correct", I'll assume
> that you are new to electronic stuff.
> First: Are you reading the 12 volts with an analog multimeter or a
> digital multimeter? An analog meter may not be sensitive enough to tell
> you whether you are getting 12.0 volts or 12.5 volts.

Pure nonsense.

Ignore everything else this IDIOT has said.

spaco

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Oct 14, 2008, 10:45:29 PM10/14/08
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Dear Eeyore:
I am surprised that you thought it necessary to comment as you did.
What was wrong with my post that set you off?
Please be specific so I won't make the same mistakes again. I am a
little new to PV, but I've been around electronics and batteries for
over 60 years.
I have seen many inexpensive analog multimeters that have only about
one meter needle distance on the scale between one "volt" and the next.
Add to that a possible inaccuracy problem in the divider resistors,
and the problem I detail can easily occur, especially to someone who may
be in the learning mode.

If the OP IS experienced in this field, and was affronted by my advice,
he/she should contact me off list to discuss the issue farther.

Pete Stanaitis
-------------------

Eeyore

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Oct 15, 2008, 9:51:27 AM10/15/08
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spaco wrote:

> Dear Eeyore:
> I am surprised that you thought it necessary to comment as you did.

Your nonsensical comment about analogue meters ! How do think they developed
stuff like radar without DMMs ?

Graham

David Williams

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Oct 15, 2008, 4:29:37 PM10/15/08
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-> > digital multimeter? An analog meter may not be sensitive enough to tell
-> > you whether you are getting 12.0 volts or 12.5 volts.

-> Pure nonsense.

It may be true if he's got the meter switched to a 0 - 200 volt range.

Older instruments tend to need more intelligence to use properly.

dow

spaco

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Oct 17, 2008, 12:29:49 AM10/17/08
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Well, Eeeyore, they didn't use $2.95 HF multimeters to develop radar. I
was around then. We had very expensive analog meters with mirrored
scales and complete calibration departments to make sure things were as
accurate as possible for the day.
An Oscilloscope was more useful than a voltmeter anyway.
But, even back then, most of us in the electronics business were
using vacuum tube voltmeters so as to read inputs with a high impedance
device so as not to negatively affect the source. As far as rf
amplifiers go, we weren't looking at parts of volt very often since the
early stuff was vacuum tubes. B+ voltages of hundreds and thousands of
volts if I recall. I have a 1960's Westinghouse induction heater here
that has 10,000 volts on the plates.
As early as the mid 1950's we had "digital" readouts at one place I
worked. Those meters (Beckman was one of the big names, IIRC) cost
several hundred (1950) dollars each.
We need more info from the OP if we are to more accuratly diagnose
his/her problem. That's why I proferred the thoughts that I did.

Pete Stanaitis
-------------------------

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