How do we test our solar panels??

[Robo]

Open invitation for our resident solar experts to explain in layman terms--
How to test our 4x4, trailer & caravan etc solar panels.
What's equipment needed?.
How to go about it safely for you, your panel & equipment.
Testing the voltage range?.
Testing for amps out put?.
What to look for to decide something is wrong with the panel.:o

[the evil twin]

You will need a multimeter (Volts and Amps)
Your panel should have a little sticker or plate on it otherwise Google is your friend
That should tell you the "Open Circuit" voltage and "Short Circuit Current"

Place the panel so it is in full Sun (duh) and as close as you can get it to 90 degrees to the Sun position
With nothing connected to the Panel;
Set the Multimeter to DC Voltage and measure the output voltage
Set the Multimeter to DC Amps and measure the output current (ensure your meter has a high enough scale)

The results should match the panel specs on a new Panel BUT panel cells deterioate so depending on age you may be down a bit
Rule of thumb... On a good panel it shouldn't drop more than 1% per year IE a 5 year old panel should be 95% or better
Shitty Panels can be a tad worse
Shitty Chinese panels can be a lot worse

[Cuppa]

http://www.selectsolar.co.uk/cat/171/testing-your-solar-panel-regulator

Never harms to say the same thing using different words.

[Robo]

This is the scenario on a new flexible mono 100w panel.
Measuring directly with meter.
Getting good voltage sunny day 21+ volts.
But a low 1/4 of 1 amp directly to meter, yes only point 23 of a amp.

But Connect a battery inline and it jumps to over 4+ amps.
please explain.
ignore the pics 19 volts it started to cloud over, but you can get the idea.
63323.
63324

[BillsGU]

Not sure exactly what you are doing - but - if you connect a multimeter measuring amps directly across a power source (battery, generator or solar panel) you will have a HUGE short circuit. If your power source has some sort of regulation or protection it will basically shut down and show either zero current or a very small amount of current, or you will blow the fuse in your multimeter and then it will either give you zero or sometimes spurious readings (depending on the type of meter).

If you place a battery in series with the panel and the ammeter your current reading will depend on the charge state of the battery.

[Cuppa]

An easy to follow youtube video. Note the panel being shaded whilst connections made.


https://www.youtube.com/watch?v=Hey1QZkYFSQ

Robo, your diagram doesn’t show a regulator between battery & panel?

[Robo]

Yep correct no reg in the solar panel "supplier's testing diagram".
However it did work giving 4.5 amps via a small 7 ah battery I had sitting on a shelf.
yes to hi for that battery but it was only for 2 sec's.

I didn't test via my reg, it's fixed in van with 150w panel hooked to it and its 100ah battery is full.
If the load connected to it is full, then output would be little with reg and test is sorta void?.
I'll try it, need to disconnect other panel first.
That's why I posed the question here for everyone else to see etc, and confirm I was going about it correctly.
It would seem the suppliers test confirms panel is working , yes??.

humm, Cuppa the above link didn't use a regulator to test for amps only a meter.

[threedogs]

Pretty sure ET suggested you need a load or resistance to be able to register AHs.
connect the battery first too, I think your values are fine

[Robo]

Pretty sure ET suggested you need a load or resistance to be able to register AHs.
connect the battery first too, I think your values are fine
Nar not that I noticed.
Place the panel so it is in full Sun (duh) and as close as you can get it to 90 degrees to the Sun position
With nothing connected to the Panel;
Set the Multimeter to DC Voltage and measure the output voltage
Set the Multimeter to DC Amps and measure the output current (ensure your meter has a high enough scale).

All good, we're All here to help one another. keep it coming.

[Bob]

This is my setup which allows monitoring of Volts & Amps from Panel

http://www.redarc.com.au/products/product/20a-solar-regulator/
with
http://www.batterybusiness.com.au/store/product_detail/redarc-srp0240-rm-remote-monitor-for-srp0120-srp0240

Pic of installation

http://www.nissanpatrol.com.au/forums/images/imported/2015/09/300.jpg

[Robo]

Thanks Bob.
I didn't want to just hook it up and hope for the best, being an ebay panel, & not wanting to damage vans solar equipment.
It's sort of a 2 fold thread.
I was trying to make sure I hadn't received a suspect panel, especially being a novice to solar.
and 2, another way for others to learn along the way.
cheers.

I love free camping and don't love things go wrong.
Especially with 3 women looking at ya the wrong way!!.

[the evil twin]

Thanks Bob.
I didn't want to just hook it up and hope for the best, being an ebay panel, & not wanting to damage vans solar equipment.
It's sort of a 2 fold thread.
I was trying to make sure I hadn't received a suspect panel, especially being a novice to solar.
and 2, another way for others to learn along the way.
cheers.

I love free camping and don't love things go wrong.
Especially with 3 women looking at ya the wrong way!!.

Test it the way I suggested (which is same as Vid and other links).

You can't properly test them with anything in circuit like Batteries or Regs
You have to use the Panel and only the Panel.

You have to short the Panel to see the max current.
The panel (on its own) cannot put out any more current than it's short circuit value no matter what you do
The only thing you can damage is the fuse in the Multimeter on the Amps scale if you use too low a scale.
Anything else in circuit will affect the performance and readings and may indeed let the smoke out

[Bob]

I would do what ET suggests as his knowledge is far superior to mine on this subject

[the evil twin]

I would do what ET suggests as his knowledge is far superior to mine on this subject

Sure goes against the grain to deliberately short things out eh... :driving2:
Every time I do it accidently I need the fire extinguisher :furious:

You are 100% right about not doing it with a battery or other source in circuit.

[Cuppa]

I wasn’t trying to suggest that you should conduct the test with via a regulator, I was just wondering if that is what you had done & had ommitted to mention it.

If you have done as per the video & ET (& ensured the panel was shaded when making the connection ) I have no idea why your short cicuit amps would be so low unless the connection was bad or a problem with the multimeter.

[the evil twin]

Related info but possibly deserves a thread of its own...
Copied from threads on other Forums but source is from Bainbridge regarding low (poor) performance of DC DC chargers, MPPT regs and Panel Outputs.

The D250 S dual will work with a panel as low as 50 watts as we have tried it in the workshop - but as it has an MPPT inside it, the losses can be quite high with such a small panel against a PWM solar charger. PWM means - Pulse Width Modulated; and MPPT means - Maximum Power Point Tracking.

Also, with higher temperatures in Australia an MPPT on low panel outputs is not as efficient. The D250S Dual was originally designed in Sweden where it’s very much colder.

Ideally if you can go up to panel size of 300 watts it would be much better on the D250 S. The open circuit voltage on your panels needs to be no higher than 22 volts DC whatever panel wattage you use on a D250s dual.

At such low power levels, using a PWM charger will be more efficient, as you have already found out. On the other hand an MPPT charger is better than a PWM unit, when it comes to using cheaper quality panels and also obtaining the maximum POWER ( not CURRENT ) for your battery.

The following link will explain why an MPPT ( as used in the D250S dual ) is operating differently to a cheaper PWM solar charger at low power levels >

http://solarcraft.net/articles/comparin ... ntrollers/

Regards;
Kimbal Summers
Warranty Technician
Bainbridge Technologies

[Robo]

I tested it with a multi meter and struck very low amps.
Ok I'll look it up, Yep I was doing it correctly.
Well I need to confirm it, a couple of ways to get it swapped over or something.
On this site I know there's a few experts and proceed to get answers/confirmation.
@ the same time I hit the seller up for a potential DOA panel, in return get his test procedure which shows the panel is working almost to its rated capacity wtf.
Also seller tells me AS the panel is putting out 18-22 v there will be nothing wrong with it!

meters ages---analogue is + 20yrs old & digital is 6 mths old.
arhhhhhh.
didn't have time to touch it today, sunny again tomorrow, try again.

[the evil twin]

This is the scenario on a new flexible mono 100w panel.
Measuring directly with meter.
Getting good voltage sunny day 21+ volts.
But a low 1/4 of 1 amp directly to meter, yes only point 23 of a amp.

But Connect a battery inline and it jumps to over 4+ amps.
please explain.
ignore the pics 19 volts it started to cloud over, but you can get the idea.
63323.
63324

In the pictures... the Voltmeter is reading 18 Volts so there is no short circuit which is why the Ammeter reading is so low.
Unfortunately the pics don't show how they are connected

Did you try them one at a time?

[Robo]

In the pictures... the Voltmeter is reading 18 Volts so there is no short circuit which is why the Ammeter reading is so low.
Unfortunately the pics don't show how they are connected

Did you try them one at a time?

Yes volts then amps 1 at a time, with digital m, & struck issue.
owning 2 meters thought I'd give it a go, and was still getting same readings.
(don't think I used analogue by its self).
meter side by side picture was both connected at same time to respective posts.
being independent meters that should work!
being that each measuring different things the panel is supposed to be doing at the same time.
both connected same time was really done for the pic for seller and he never asked how or why etc.

Soon as I clear the noggen I'll be outside again, 20 yrs night shift bit slow to get going first few days of holidays.

[Cuppa]

I remain confused about the .23A but believe if the panel was putting out the expected amps when connected to the battery then it must be ok.

[Maxhead]

I'm confused why the analog meter is not set to 25v DC range and we're saying its reading 18/19V....must be missing something

[Robo]

Now I'm awake, remember analog meter only measures to 250 ml amp, that's why I didn't use it, and why I own the other.

AND guess what? Now it's reading/operating correctly, actually getting 6.07 amps( if I aim it at the sun), which is juust over the rated amps.
Ida know what happened, I know I tested it correctly before.
(May be a spike upset meter?)
Conducted this test before and achieved correct result first time, but this one threw me a curve ball.
Another pic showing good result.
All's well that ends well.
Thanks for the input gents.
Merry Christmas.63375 63376

[the evil twin]

I remain confused about the .23A but believe if the panel was putting out the expected amps when connected to the battery then it must be ok.

Yes, agree


I'm confused why the analog meter is not set to 25v DC range and we're saying its reading 18/19V....must be missing something

The Micronta (which is a decent bit of kit actually) is set to 25 VDC.
They are a tad different in that you read the scale selection against the dot on the face at 12 O'clock not the knob position like the Flukes etc.
Not intuitive these days I know but makes sense to us pre-decimal currency technicians as a lot of gear was like that when we calibrated the Ark


Now I'm awake, remember analog meter only measures to 250 ml amp, that's why I didn't use it, and why I own the other.

AND guess what? Now it's reading/operating correctly, actually getting 6.07 amps( if I aim it at the sun), which is juust over the rated amps.
Ida know what happened, I know I tested it correctly before.
(May be a spike upset meter?)


I thought it would be the E.T. factor also known as finger trouble (cause it happens to me all the freakin' time)

Your theoretical Isc max is 5.96 Amps, 5.81 is a very good result in the paddock.

[Maxhead]

The Micronta (which is a decent bit of kit actually) is set to 25 VDC.
They are a tad different in that you read the scale selection against the dot on the face at 12 O'clock not the knob position like the Flukes etc.
Not intuitive these days I know but makes sense to us pre-decimal currency technicians as a lot of gear was like that when we calibrated the Ark





Yes, makes sense now. I have used a few old school meters but obviously not from around the ark era ...LOL Could have been something to do with the heat and beers too. :)
Thanks for that

[threedogs]

These are handy

http://www.ebay.com.au/itm/Digital-LCD-Watt-Meter-Battery-Balance-Ammeter-Amp-Analyzer-60V-100A-DC-RC-Volt-/171874051824?hash=item28047de6f0:g:K-0AAOSwLVZVuJGt

[the evil twin]

These are handy

http://www.ebay.com.au/itm/Digital-LCD-Watt-Meter-Battery-Balance-Ammeter-Amp-Analyzer-60V-100A-DC-RC-Volt-/171874051824?hash=item28047de6f0:g:K-0AAOSwLVZVuJGt

Sure are, suprisingly accurate as well
I've used about 10 of them here and there over the last 5 years or so and only had one shit itself and one other that swallowed a bit too much current for too long.

Only things that give me the irrits are they have no mounting points (I either glue or velcro them) and very short fly leads which makes terminating them with anything other than plugs a bit of a PIA.
Anderson Power Pole style are the go for a nice compact solution.