12v solar on roof of 4wd

Hey guys, I'm sorry if this isn't posted in the correct spot but it's the first time I have been on here and I'm trying to figure out the site on the iPad.
Got a question for the 12 guru's. I have just put a 130w panel on the roof of my Navara and have it hooked up to my ArkPak which has a 120ah AGM battery that is in the canopy, I have used 5mm (15a dual core) wire (auto elec told me to use it) and it is approx 3.5 to 4mtrs long. I know we haven't had the brightest sun in melbourne lately but the most I can get out of the panel when full sun has been on it is 19w but most of the time is about 12w, I know I'm not going to get the full 130w pumping into it but I thought I would be getting more that 12 to 19w into it. It has a PWM controller but was told I should get a MPPT controller?
Any help would be appreciated
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Reply By: steved58 - Sunday, May 22, 2016 at 18:17

Sunday, May 22, 2016 at 18:17
I would guess the battery is nearly full discharge it a bit or put a reasonable load on the battery then see how the panel goes
Cheers steve
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Follow Up By: Magoo3338 - Sunday, May 22, 2016 at 18:38

Sunday, May 22, 2016 at 18:38
Nah it's sitting at about 75%. I have my cfx50 connected to it all the time
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Reply By: Life Member - Fred B (ex-NT) - Sunday, May 22, 2016 at 18:23

Sunday, May 22, 2016 at 18:23
Where is your regulator? On the panel or close to the battery. The closer to the battery the better.
regards
Fred B
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Follow Up By: Magoo3338 - Sunday, May 22, 2016 at 18:37

Sunday, May 22, 2016 at 18:37
Yeah it's about 400mm of wire between the controller and the battery.
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Reply By: Frank P (NSW) - Sunday, May 22, 2016 at 18:36

Sunday, May 22, 2016 at 18:36
Melbourne is well south and at this time of year has a low sun.Melbourne autumn weather is often sunny and glorious to be outdoors in, but often very hazy, which can have a big effect on PV output. Horizontal panels on the roof of your vehicle at low latitudes in late autumn with possibly hazy sun - you have everything working against you.

Having said that, I would have thought you'd get a bit more than 12 to 19 watts.

If you can move your panel, try getting it pointing directly to the sun - shadow directly behind the panel and the shortest possible shadow length - and see if that makes a difference.

Cheers

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Follow Up By: Magoo3338 - Sunday, May 22, 2016 at 18:39

Sunday, May 22, 2016 at 18:39
Yeah I know exactly what ya mean, but I also thought it would be pulling in a little more that what it is as well
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Reply By: Robin Miller - Sunday, May 22, 2016 at 18:53

Sunday, May 22, 2016 at 18:53
Something is clearly wrong so it should be fixed well before considering the small improvement MPPT provides.

I will assue here that you don't have much test gear otherwise I say to put a good load on your panel and measure current , so here is a simple way to test it.

First if the whole panel is in sun (not shaded) then you should be getting a minimum of 60+ watts out of it from 11 till 2pm.
Thats out of panel with no regulator connected.

To check this get a dirt cheap car headlight globe (70-120w) , disconnect panel from the rest and put globe across the panels output wires , it should glow brightly and with luck blow the globe (hence cheap is good).

The above tells you the panels ok , I'd have to know more about any test gear , and or how the regulator is connected to go further.

P.S. I save my headlights globes if just high or low beam fails for just these sorts of reasons.


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Follow Up By: Magoo3338 - Sunday, May 22, 2016 at 19:06

Sunday, May 22, 2016 at 19:06
I out a multi meter on it today when in he sun and it was putting out 12.9v. I didn't test it before the regulator though
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Follow Up By: Robin Miller - Sunday, May 22, 2016 at 19:18

Sunday, May 22, 2016 at 19:18
Ok Magoo , when you get a chance measure just the panel, 12.9 indicates
your system is at least working a bit, and maybe also be working correctly.

But its the panel itself that we need to know is good.

Robin Miller

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Follow Up By: Magoo3338 - Sunday, May 22, 2016 at 19:27

Sunday, May 22, 2016 at 19:27
Yeah no worries. I'll check it out tomorrow if the bloody sin comes out hahaha
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Follow Up By: Magoo3338 - Monday, May 23, 2016 at 19:06

Monday, May 23, 2016 at 19:06
Yeah panel is all good, 21.6 volts. Then checked it after the reg and it had 14v
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Follow Up By: Robin Miller - Monday, May 23, 2016 at 21:26

Monday, May 23, 2016 at 21:26
Where did you find the sun - I reckon we had about 3 seconds worth at knox city.

While 21 volts is fine , its the under load test thats going to count - and I think there will be even less sun to-morrow !
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Follow Up By: Magoo3338 - Tuesday, May 24, 2016 at 08:18

Tuesday, May 24, 2016 at 08:18
Haha I'm in melton and it was sunny for the whole day. I'll have to wait until the weekend now as I'm at work when the sun is out
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Reply By: Member - Scrubby (VIC) - Sunday, May 22, 2016 at 18:57

Sunday, May 22, 2016 at 18:57
I am no expert on solar but your figures sound more like Volts, not Watts, 19 volts unregulated will give you something like 7amps output ( I think).
How did you arrive at the 12 to19 w figures ?

Someone please correct me if I am wrong.

Scrubby.

I don`t know where i`m going but i`m enjoying the journey.

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Follow Up By: Magoo3338 - Sunday, May 22, 2016 at 19:04

Sunday, May 22, 2016 at 19:04
Nah it's in watts, arkpak tells you how much is coming in and going out when under load
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Reply By: Magoo3338 - Monday, May 23, 2016 at 17:02

Monday, May 23, 2016 at 17:02
So I have tested the panel directly and it's working fine. Was putting out 21.6v and it is putting out 14v after the regulator into the battery but it still only produced 28watts when i tilted it towards the sun at midday? Maybe my reg is buggered?
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Reply By: Mick O - Monday, May 23, 2016 at 17:55

Monday, May 23, 2016 at 17:55
Magoo something is amiss here and I think it's in the way you are reading the outputs from your panel.

On a 125 Watt panel, the specifications are thus;

Mono-Crystalline 125W
Max Power Voltage 17.8V
Max Power Current 7.02A
Open Circuit Voltage 21.9V
Short Circuit Current 7.58A
Module Efficiency 17.3%


The output from the panel is measured in Volts and amps, not watts. The maximum ampage (electrical current) output by the panel is a bit over seven amps at 18Volts or a little higher if you run the panel as open circuit (no controller on the panel).

Your output of 19 VOLTS is pretty much spot on. Your ampage (The electrical current output from the panel) should be between 5 and 7 amps. It's not Watts and that's what is causing you the confusion.

Generally, when you're talking about watts (W) in the context of electrical power, you're talking about instantaneous power generated or consumed by a given device: How much power is being generated or used at a given moment? your 130 att panel will produce 130 watts of power each hour in PEAK sunlight and in optimal conditions. Normally it's lower than this because of the angle of the sun, the panels and other factors.

Watts = amps x volts so in the case of the panel above 17.8 x 7 = 125 (ish)


Have a read of this article it's excellent for demystifying solar;

Electricity for camping

Cheers
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trip would doubtless be attended with much hardship.''
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Follow Up By: Magoo3338 - Monday, May 23, 2016 at 19:05

Monday, May 23, 2016 at 19:05
Appreciate ya input but I'm defiantly talking watts. My arkpak tells you how much nett watts are coming in(when charging) and going out(when under load. I have had it sit in direct sunlight all day and it was a very clear day in melbourne today and my battery sat at the same % of charge all day. I would expect with a 130w panel for it to at least charge it from 80% charge on a clear day quiet easily I checked the panel today (with a multi meter) for its voltage before the regulator and it was producing 21.6v and at the battery (connected to the regulator) it has 14v, I can't figure out why it's charging so slow
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Follow Up By: Peter - Monday, May 23, 2016 at 19:31

Monday, May 23, 2016 at 19:31
Where have you got solar connected.
According to manual terminals 7 and 11, isolator switch turned on.
this will bypass smart charge pcb.
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Follow Up By: Magoo3338 - Monday, May 23, 2016 at 20:00

Monday, May 23, 2016 at 20:00
I have it connected to the terminals on the left hand side of it
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Follow Up By: Peter - Monday, May 23, 2016 at 20:20

Monday, May 23, 2016 at 20:20
So According to manuals at http://arkcorp.com.au//Content/manuals/ArkPak%20AP730%20manual%20120315.pdf
Solar panels should be connected to main big terminals (Done)

Pack switched on at isolator.

The front meter is then disabled from reading current from solar panels coming in.

A test would be open box and connect solar direct to battery.
Also when charging batteries the closer they are to fully charged the less current they will absorb.

Best advice is to get multimeter If it has a current setting at least 10 a and put in series on positive charge lead of solar panel this will definitely tell how much charge is going in.
Another is to using a multimeter on Volt setting after a day of charging leave over night with nothing connected the Voltage should read 12.8 v This is generally what fully charged batteries settle to.
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Follow Up By: Magoo3338 - Tuesday, May 24, 2016 at 08:20

Tuesday, May 24, 2016 at 08:20
Sweet, when I get a chance I'll try that out
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Reply By: Peter C61 - Tuesday, May 24, 2016 at 13:17

Tuesday, May 24, 2016 at 13:17
Is the panel rated 130w at 12V or 240v? It will tell you on the back. If it is rated at 240v than it will only produce 6.5W at 12v. Don't waist your money on a MPPT controller as they are only a benefit for large systems. There are articles on the net that explain why.
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Follow Up By: Magoo3338 - Tuesday, May 24, 2016 at 13:34

Tuesday, May 24, 2016 at 13:34
Nah it's 12v
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Reply By: HKB Electronics - Tuesday, May 24, 2016 at 20:30

Tuesday, May 24, 2016 at 20:30
To test the panel, remove the regulator, face the panel at bright sunshine, using an amp meter that can handle the current to a short circuit current test across the panels terminals, ie place the red probe on the positive terminal and the black on the negative terminal at see what it reads, you should get the same as shown on the panels label for short circuit current or there abouts.

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