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Solar panel charging problem.
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usermikejkay
Posted: 20 May 2020 8:52 PM
Subject: Solar panel charging problem.
 


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Bit of a disaster this afternoon. Went out to the M.H. which has not been used for three weeks to find that the habitation battery was dead. And I mean dead, 9.9v on the Votronic monitor.
I immediately plugged in the EHU on and the Votronic showed a charge which eventually increased to 18.8 amps.
I have two 80w solar panels which were fitted by Travelworld when I bought the van four years ago and they have worked flawlessly ever since. Without the EHU the monitor shows no charge at all.
I have had a quick check but can't find a blown fuse or any obvious reason why this should have happened.
Does anybody have any ideas as to where I should start looking/

Edited by mikejkay 2020-05-20 9:08 PM
usercolin
Posted: 20 May 2020 10:14 PM
Subject: RE: Solar panel charging problem.
 


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First job would be check the voltage going into the charge controller, then whats coming out.
userPaul-
Posted: 21 May 2020 8:10 AM
Subject: RE: Solar panel charging problem.
 


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I would go round and check all connections from top to bottom, its recommended by some solar controller manufacturers to do it yearly, and as said you should check the power as you go.

Edited by Paul- 2020-05-21 8:11 AM
userStuartO
Posted: 21 May 2020 10:06 AM
Subject: RE: Solar panel charging problem.
 


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My solar panels stopped working a few years ago and I took it to the dealer (Solar Solutions) who had supplied and fitted them about six years earlier. They had to take the panels down from the roof to gain access to the diodes, which they replaced and then refitted the panels. Back to full function, bill was £120 which seemed good value.
usermikefitz
Posted: 21 May 2020 11:50 AM
Subject: RE: Solar panel charging problem.
 
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I suspect the panels, if the flexible type, have failed. To confirm this disconnect the panels from the controller and measure the open circuit voltage, then if you are confident using your multimeter, measure the short circuit current. Assuming the panels are wired in parallel you should see, with some sunshine, around 20 volts and a current of over 4 amps.
If the readings are showing healthy panels, check the voltage on the controller input to confirm there is a connection to the batteries, reconnected the the panels and test the controller output voltage to confirm the controller is functioning correctly.
Assuming there are no failed connections or fuses, then if the batteries are not charging it must be failed panels or failed controller.
There are known issues with early versions of Voltronic controllers causing failures so this maybe the promlem.

Mike
usermikejkay
Posted: 21 May 2020 3:02 PM
Subject: RE: Solar panel charging problem.
 


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Well, the good news is that the battery seems to have survived. I left on charge yesterday evening and at 0200 today I disconnected the EHU, The Votronic showed 99% cgarge and the lights ansd step were working. Today, at about 1400, the meter was still showing 99%

The panels are, unfortunately, flexible and are stuck to the roof. I didn't want flexible panels but Travel World claimed that there was insufficent room to fit150w of rigid panels. Now I am going to have to pay the price,

This afternoon I am going to check the solar panel output. Not an easy job as the van is usually parked about 300mm away from a fence and the Solar Charge Regulator is well tucked away. I am not a contortionist
userPaul-
Posted: 21 May 2020 4:11 PM
Subject: RE: Solar panel charging problem.
 


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Flexible don't seem to have a very long shelf life at the best of time, some go opaque with reduced output within a few years.

I hope its not the case with yours.
usermikejkay
Posted: 21 May 2020 6:49 PM
Subject: RE: Solar panel charging problem.
 


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I thought that I'd cracked it. I pulled the leads from the panels out of the LR1218 regulator and got 0 volts . Then I noticed that the earth lead was floppy and when I stripped off the heat shrink insulation I found that the wire was disconnected from the spade terminal. Ah ha I though! Then I measured the voltage across the leads and got only 9.8v. . I must have pulled the spade terminal off myself when removing it.

Anyway, I then crimped on a new spade terminal, nice and tight so at least that's fixed. Travel World when fitting the regulator nfor some reason omitted any fuses despite the fact that in-line fuses come as part of the fitting kit. All other fuses are OK. The odd thing is that the Votronic display flicks between showing no charge and showing 0.1 or 0.2 amps. Odd, as the habitation battery is now showing 12.7 volts

Checked on the roof and can see nothing amiss. The cables run from the panels to the roof gland in what looks like household conduit. No sign of any knocks or abrasion. Looks like general failure of the panels themselves.

Any body have any ideas? If it is the solar panels that have failed it has happened pretty abruptly.

Could have been worse. I was due to cross over to the Hook of Holland next monday. At least I've got plenty of time to fix this.
usermikejkay
Posted: 21 May 2020 6:51 PM
Subject: RE: Solar panel charging problem.
 


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Paul- - 2020-05-21 4:11 PM

Flexible don't seem to have a very long shelf life .
Just over four years. I'm not very happy.
usercolin
Posted: 21 May 2020 6:57 PM
Subject: RE: Solar panel charging problem.
 


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For future reference, if you can get the meter onto the contacts you don't need to remove leads to check voltage. I just put the meter across the screws.
usermikejkay
Posted: 21 May 2020 11:37 PM
Subject: RE: Solar panel charging problem.
 


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colin - 2020-05-21 6:57 PM

For future reference, if you can get the meter onto the contacts you don't need to remove leads to check voltage. I just put the meter across the screws.


I found that when I measured the voltage with the solar panel plugged into the controller I was getting 12.7 volts which I presumed was the battery voltage
userDerek Uzzell
Posted: 22 May 2020 8:34 AM
Subject: RE: Solar panel charging problem.
 


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mikejkay - 2020-05-21 6:51 PM

Paul- - 2020-05-21 4:11 PM

Flexible don't seem to have a very long shelf life .
Just over four years. I'm not very happy.


This critical USA YouTube review may be of interest

https://www.youtube.com/watch?v=onMZ_dRSFUs
userCharles
Posted: 22 May 2020 9:10 AM
Subject: RE: Solar panel charging problem.
 
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Derek Uzzell - 2020-05-22 8:34 AM

mikejkay - 2020-05-21 6:51 PM

Paul- - 2020-05-21 4:11 PM

Flexible don't seem to have a very long shelf life .
Just over four years. I'm not very happy.


This critical USA YouTube review may be of interest

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


Iteresting how he mentioned at the end about even the new ETFE ones are junk too. I remember someone on one of the forums was going to buy the new type that 'don't suffer from premature failure' and he was determined they'd be fine, was a couple of years ago now so wonder how they're doing.
usercolin
Posted: 22 May 2020 11:55 AM
Subject: RE: Solar panel charging problem.
 


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mikejkay - 2020-05-21 11:37 PM

colin - 2020-05-21 6:57 PM

For future reference, if you can get the meter onto the contacts you don't need to remove leads to check voltage. I just put the meter across the screws.


I found that when I measured the voltage with the solar panel plugged into the controller I was getting 12.7 volts which I presumed was the battery voltage


With every charge controller I've had, if you measure the voltage on the input side it will show the panel output, if the input side is showing battery voltage(confirm by doing it with panel covered or at night, the charge controller is odd or knackered.
usermikejkay
Posted: 22 May 2020 2:14 PM
Subject: RE: Solar panel charging problem.
 


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Surely, if I am getting 9.8v across the disconnected panel wires that indicates a problem "upstream"? Most likely failed panels.
One other thing occurred to me. I have two 80w panels wired in parallel. If one has failed could the imbalance be causing the problem. I will be trying to test each panel independently but I'm having trouble getting access to the wiring
usermikejkay
Posted: 22 May 2020 2:28 PM
Subject: RE: Solar panel charging problem.
 


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This critical USA YouTube review may be of interest

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

I wish I'd seen that four years ago
usercolin
Posted: 22 May 2020 2:39 PM
Subject: RE: Solar panel charging problem.
 


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mikejkay - 2020-05-22 2:14 PM

Surely, if I am getting 9.8v across the disconnected panel wires that indicates a problem "upstream"? Most likely failed panels.
One other thing occurred to me. I have two 80w panels wired in parallel. If one has failed could the imbalance be causing the problem. I will be trying to test each panel independently but I'm having trouble getting access to the wiring


If you are sure you measured across the input terminals and with panels connected you got 12.7 , and across wires disconnected you got 9.8 if so something else is amiss, all charge controllers I've known have blocking diode to stop battery feeding back to panels. Are you sure nothing is shading panels intermittently or at different times of day, as with some panels even a small amount of shaded area can have a big effect.

Edited by colin 2020-05-22 2:40 PM
usermikejkay
Posted: 22 May 2020 5:43 PM
Subject: RE: Solar panel charging problem.
 


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UPDATE - This afternoon it was overcast and I got 10.1v across the disconnected wires leading to the solar panels.

I attached a 50w 4 ohm WW resistor across the disconnected SP output and got a current reading of 3.06 amps using a clamp meter. The voltage across the load dropped to 8.3v. Doesn't quite add up

With the SPs disconnected from the LR1218 regulator I got 12.88v across the IP terminals of the regulator and 13.0v across the OP terminals of the regulator. Direct measurement of the battery was 12.85v.

When I plugged the SPs into the LR1218 regulator I got 12.85v across the LR1218 input terminals.

I then washed the solar panels thoroughly after which I got 12.77v across the disconnected SP wires. Still no indication of charging on the Votronic control panel.

P.S. Panels are in totally unobstructed line of sight with the sun.

I am at a loss. I don't want to replace the solar panels only to find that the regulator has gone belly up as well.



Edited by mikejkay 2020-05-22 5:44 PM
userBruceM
Posted: 22 May 2020 6:10 PM
Subject: RE: Solar panel charging problem.
 
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mikejkay - 2020-05-22 5:43 PM

UPDATE - This afternoon it was overcast and I got 10.1v across the disconnected wires leading to the solar panels.




If I understand you correctly you measured the voltage across the solar panel output wires whilst they were disconnected from the solar regulator and had a reading of 10.1v ?

So that means you were measuring the Open Circuit Voltage (VoC) which I would have expected to be about 20v . If you can identify the make of your panels you may be able to look up what their VoC should be.

On the face of it it does sound like the panels are fubar.

Are the panels connected in parallel or serial?
usermikejkay
Posted: 22 May 2020 6:30 PM
Subject: RE: Solar panel charging problem.
 


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Parallel.

Currently researching the cost of replacement panels. NOT flexible ones.Can't see any signs of deterioration of the panels, and this had happened so quickly.

Looks like I can fit two 100w panels, one each on different parts of the roof. Don't know why Travelworld didn't do that in the first place!

Any reason why I should not use the existing 4mm cables? Would make thing soooooooo much easier
userspirou
Posted: 22 May 2020 6:43 PM
Subject: RE: Solar panel charging problem.
 


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No reason not to if cables are ok
userBruceM
Posted: 22 May 2020 7:03 PM
Subject: RE: Solar panel charging problem.
 
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. . . and ideally they're terminated with mca connectors so that they can just be plugged in to the new panels. Alternatively you’ll probably want to purchase some mca connectors.

Out of interest, are the two panels connected together in parallel on the roof (via an appropriate connector) with just two cables then entering through the van roof? Or do both cables from each panel enter the van separately so that four cables enter through the van roof?
usercolin
Posted: 22 May 2020 7:36 PM
Subject: RE: Solar panel charging problem.
 


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I would take advice from someone who knows more about that charge controller than me, but still seems odd.
The panels seem to be defective, but make sure there isn't a shadow from even something like a skylight, as some panels are very susceptible to just the smallest shadow.
usermikefitz
Posted: 22 May 2020 11:28 PM
Subject: RE: Solar panel charging problem.
 
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More on your solar panel problems.

Quote,
'attached a 50w 4 ohm WW resistor across the disconnected SP output and got a current reading of 3.06 amps using a clamp meter. The voltage across the load dropped to 8.3v. Doesn't quite add up'

Each panels is arranged in two banks of cells with bypass diodes. ( this is typical for 36 cell panels).
If one half ( one bank) of the panel fails you would see half the nominal voltage but the current for conditions, 3 amps sounds about right. For example if the panel has 36 cells with two banks of 18, the nominal voltage for each bank is 0.6 x 18, 10.8 volts. If everything is OK the series connection of the two banks gives the nominal 20 volt output of a 36 cell panel. With a open circuit in one bank you loose the complete output in that bank due to no current path, but the bypass diode allows the functioning half to pass current to the output terminals. The drop in voltage under load is expected, the maximum power point is about 17 volts. ( but you only have half a panel).

An alternative failure mode is one of the bypass diodes has become short circuit, effectively bypassing half of the panel.

Its not clear if one or both panels have failures, as the effected one could compromise the output of the other. The usual failure mode within the panel is an open circuit in the inter connections, sometimes this creates a 'hot spot' and the damage is visible.

I think your panels are Solar Technology panels with a 5 year warranty,

https://www.solartechnology.co.uk/pv-logic/flexi-panels/

To further investigate, it would be useful to access the point where the two panels are connected together, separate, and test the OC and SC output of each.

Mike




Edited by mikefitz 2020-05-22 11:42 PM
usermikejkay
Posted: 23 May 2020 1:53 AM
Subject: RE: Solar panel charging problem.
 


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Mikefitz

I am amazed! How on earth did you work out that my panels are Solar Technology units. I've visited the website and their panels do look like mine. Particularly the "lumpy" connectors. I will check the warranty situation. ll also look to see if there is any barcode visible. Thanks for the heads up
usermikejkay
Posted: 23 May 2020 4:40 PM
Subject: RE: Solar panel charging problem.
 


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mikefitz - 2020-05-22 11:28 PM

it would be useful to access the point where the two panels are connected together, separate, and test the OC and SC output of each.



Just been uo on the roof again I have a twin cable duct each taking a single 6.74mm dia. cable (must be twin) . The join must be inside the m.h. The cables are pretty inaccessible and run behind the fridge and under the floor

I can just about access the junction boxes on the panels themselves but hey appear to be completely sealed.
userBruceM
Posted: 24 May 2020 10:06 AM
Subject: RE: Solar panel charging problem.
 
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mikejkay - 2020-05-23 4:40 PM
The join must be inside the m.h. The cables are pretty inaccessible and run behind the fridge and under the floor



Whilst the VoC reading implies that the solar panels are fubar, in your situation I’d still prefer to be able to test each panel separately before proceeding.

You mention that the cables appear to be run behind the back of the fridge. I’m unfamiliar with your van, but if it has an absorption fridge is it possible that the fridge vents were used to gain access to the back of the fridge and put a junction box there to join the two solar panel cables before continuing with a single cable run to the solar regulator?

If so then you can disconnect the panels at the junction box and check their individual VoC. If it turns out that one is ok then at least that would provide you with a holding position until you can sort out replacement ridged panels. It would also confirm that your solar regulator is functioning correctly.
usermikejkay
Posted: 25 May 2020 5:04 PM
Subject: RE: Solar panel charging problem.
 


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Well, having successfully researched the "how" via MMM forums (many thanks to all) I have removed the fridge vent covers. This revealed a mass of wires the size of my wrist all tightly cable tied together. In amongst this lot I found a single black cable the same size as those going into the roof gland and a single red wire and a single black wire, both the same size but very slightly smaller in diameter than the 4mm wire that I have used for a solar panel installation in the past. Regrettably, no sign of any joined wires.

I will have to await the outcome of warranty discussions before proceeding any further although I was tempted to cut the red wire and see what happened.

I did get a small current of 80mA, this in blazing hot sun without a cloud in the sky!

Looks as though the battery did sustain some damage, it appears to be losing charge a little bit faster than previously.

The good news is that the installation of the fridge appears excellent. Well sealed all round.
userBruceM
Posted: 25 May 2020 5:55 PM
Subject: RE: Solar panel charging problem.
 
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I’d avoid cutting any wires unless you have a good idea what the wire's purpose is.

I’d hoped that on checking the back of the fridge you’d see either two solar cables or one. Unfortunately it doesn’t appear to be that clear.

What is under the solar cable gland on the roof – ie is it a cupboard and can you therefore see both solar cables enter at that point and then somehow be routed down the back of the fridge?

It’s likely that the installers would have taken the easiest route possible for the cable run – they don’t generally try to make life difficult for themselves.
usermikejkay
Posted: 25 May 2020 9:43 PM
Subject: RE: Solar panel charging problem.
 


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BruceM - 2020-05-25 5:55 PM

What is under the solar cable gland on the roof


The gland is directly above the fridge but set in from the side of the van by about 200mm. The wires will come through on the other side of the fridge bulkhead. I might take the gland off and see if I can see where the wires go. Might get lucky.

Makes you realise how important it is to fit these things oneself. I knew exactly where the cables ran and where the fuses were on my last van because I had fitted the panels myself. Wish I hadn't been lso azy this time.

Edited by mikejkay 2020-05-25 10:00 PM
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