Testing Solar Chargers ?

[Aggie Dad]

This is a post I saved from last October but, haven't got around to trying it yet. Hope it helps!

Solar panel test
The only real way to test a solar panel is to see how much current (amps) it is putting in the battery. The little digital multimeters from Harbor Freight work well for this. Set the meter to the 200 milliamp scale. Connect the meter as shown below. Most of the feeder solar panels (6"x6") put out between 2 and 10 milliamps depending on which way they are facing, cloud conditions, etc. Larger panels will put out more current. I have one from Northern Tool that puts out around 200 milliamps. Once you complete the test MAKE SURE you switch the meter back to the volts scale. Trying to measure volts with the meter set to current will fry your meter. Don't ask how I know this.

[Aggie Dad]

Solar panel test
The only real way to test a solar panel is to see how much current (amps) it is putting in the battery. The little digital multimeters from Harbor Freight work well for this. Set the meter to the 200 milliamp scale. Connect the meter as shown below. Most of the feeder solar panels (6"x6") put out between 2 and 10 milliamps depending on which way they are facing, cloud conditions, etc. Larger panels will put out more current. I have one from Northern Tool that puts out around 200 milliamps. Once you complete the test MAKE SURE you switch the meter back to the volts scale. Trying to measure volts with the meter set to current will fry your meter. Don't ask how I know this.

[Aggie Dad]

Sorry but can't get image to copy

[LWD]

Connect your multimeter to the solar panel outputs to test it. You don't want a battery connected to it.

LWD

[Mike D]

Connect your multimeter to the solar panel outputs to test it. You don't want a battery connected to it.

LWD

Solar panel test
The only real way to test a solar panel is to see how much current (amps) it is putting in the battery. The little digital multimeters from Harbor Freight work well for this. Set the meter to the 200 milliamp scale. Connect the meter as shown below. Most of the feeder solar panels (6"x6") put out between 2 and 10 milliamps depending on which way they are facing, cloud conditions, etc. Larger panels will put out more current. I have one from Northern Tool that puts out around 200 milliamps. Once you complete the test MAKE SURE you switch the meter back to the volts scale. Trying to measure volts with the meter set to current will fry your meter. Don't ask how I know this.

Both of these methods only tests for voltage, not current and is not the correct way to test whether the panel is charging properly.

On a DC voltage circuit you have to place the meter in series between the charging source and the load to test for current.

Connect the panel to the regulator and battery.
Ensure that the multimeter is set at 10A, at least to start with. You can change the setting later if required.
Disconnect the positive cable between the battery and the regulator
Measure the operating current by connecting the +ve from the multimeter to the positive cable from the regulator, and the -ve from the meter to the positive battery terminal.
This measures the current that the panel (and charge controller) are passed to the battery. If you connect the meter the wrong way round then you will get a negative current showing.
Remember, if the battery is full it may not be accepting current, resulting in a low reading.

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[SabreKiller]

This...

I've never thought to test the amperage output. However, I have found voltage output to be a good proxy for whether they work or not. If full, direct sunlight a 6v panel should be putting out about 9 volts while a 12 volt panel should be putting out about 15v. Even in indirect sunlight those numbers should be about 7 and 13 volts. If you aren't getting those numbers, chunk the panel and get a new one.

LWD

I do this first when I have a battery that won't keep a charge.

[splitbeam145]

As stated above you have to be putting out enough current to charge the battery. Voltage output is irrelevant.

You need a battery that is a bit drained and then put your meter in series with the + lead of your panel to the + terminal of your battery to test current output.


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x2

[kmitchl]

As stated by others, the only way to evaluate a solar panel is the measure the current (ma) output to the battery. I only wish I could convince several members on our lease of this.

What I find is the feeder solar panels usually only put out a few ma which is sufficient to keep the battery at full charge.

[quarterback]

The real question (to me anyway) is what amperage is sufficient to keep a battery charged? I understand that it depends on usage, age of battery, etc.

Here's another question related to this thread: What brand/style battery works best for a 6 volt feeder in everyone's opinion?

[Mike D]

The real question (to me anyway) is what amperage is sufficient to keep a battery charged? I understand that it depends on usage, age of battery, etc.

Here's another question related to this thread: What brand/style battery works best for a 6 volt feeder in everyone's opinion?

That depends on how much current you are using. Generally just for a feeder that throws twice a day 60-100ma should
be more than sufficient.

I don't know that any one brand is better than the other.


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[sotol]

Aha!!! I have been having trouble with a feeder forever. I kept checking like I was told and the solar panel was well over 12 volts. I checked the amps on it today and it showed a whopping 1 ma. Tried a new solar panel and it maxed out at 82 ma.
I am saving the old one for a training tool at the lease. lol.

One question for you who know stuff. Where do you get your spade lug connectors. The ones I. Get at home depot or Auto Zone are not consistent. Some are sloppy loose and some are a struggle to put on or take off.

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[hog_down]

I use the yellow male connectors from any auto parts store

[ranchdog]

Yep, here is my same results testing my Solar panel. Voltage, very little amps. I have pictures in this thread that may help someone else trouble shoot these issues

http://discussions.texasbowhunter.com/forums/showthread.php?t=158031

Ranchdog

[kmitchl]

The real question (to me anyway) is what amperage is sufficient to keep a battery charged? I understand that it depends on usage, age of battery, etc.

Here's another question related to this thread: What brand/style battery works best for a 6 volt feeder in everyone's opinion?

To keep the battery fully charged you need to replace the charge that you use plus have a little margin for days the sun does not shine. This is calculated by amp-hours. Charging a battery at 1 amp for one hour puts about 1 amp-hour charge into the battery. Likewise discharging at 1 amp for one hour removes 1 amp-hour of charge from the battery. The larger 12 volt feeder batteries hold 7 or 8 amp-hours of charge.

I doesn't take a lot of amps from a solar panel to keep a battery topped off. Spinning for 10 seconds twice a day at a current of 3 amps would require

Spin time = 10 *2/60/60 = .0055 hours/day
Spin time * Amps per spin = 3*.0055 = 0.0166 amp hours = 16.6 ma-hours.

So a solar panel charging at about 2 ma for 8-9 hours would be enough to keep the battery topped off. This neglects the current required to operate the clock, however, this is usually very small in comparison to that required to run the spinner motor.

[ranchdog]

The pic below and is how you test a solar panel and what a Good solar panel test like (amperage not voltage)

First make sure your meter measures DC mA (Direct Current milli Amperes) usually they go up to 400 ma on one switch setting and 1.0 A on another setting. So make sure your on the correct mA setting on your meter. In this photo the meter is set on mA (max for my meter is 200 mA). A solar panel like we use on our feeders usually max out around 60-70mA but check your panel.

So hook the meter up in Series (inline as shown below) You will need a good battery, not a completely dead one that won't take a charge. So you can see that the solar panel is putting out 69.2 mA. The voltage was 18 Volts I measured but don't show here but will below on the bad one. But as you will see in the next set of pictures / description what a bad solar panel looks like.


Now what a bad solar panel looks like.

In the picture below I simply measure the voltage and I get 17.69 volts. So you would think it is working. HOWERVER, in the second picture where I measure the current notice that it is not putting out but 0.6 mA. It is bad and will not charge your battery. It should be putting out around 60-70 mA.


Here is the 0.6 mA. This is not working and is a bad solar panel. Throw it in the trash. You should be getting around 60 mA in FULL SUN. On a cloudy day it might drop down or if your battery is really charged. This test was done at the same time as the good solar panel in the above posting less the 1 minute apart so the sun was basically the same intensity.


Good Luck, Ranchdog