Adding a 2nd solar panel in parallel

[Hoovie]

Bolt with (nylock) nuts will be secure but a faff to both secure and remove if using in conjunction with stuck down mounts
Pop-rivets will rust and work loose just as much - and probably more so - than screws.

I would - and always do and have - use self-tappers (into a pilot hole) if going directly into the frame. These are secure, reliable and are easy to check when you are doing your general periodic roof checking and if need be replace.

 

[Peregrinator]

Reason I would not use self-tappers, some U-Tubers self-tappers have become loose over time.

 

[Hoovie]

Reason I would not use self-tappers, some U-Tubers self-tappers have become loose over time.

yup. And we know Vanlife U-Tubers are the pinnacle of excellence

 

[VXman]

Only thing I would change, would be the brackets, I would use the ones that go the full length of the panel on the front facing only, as it would be more aerodynamic and protect underneath

Yes, I got some of those. Bargain on ebay at £27. Good quality and match the ones on my present panel perfectly, although those are integrated into the panel.

Aluminium Solar Panel Mounting Brackets for Panels up to 67cm Wide. Sale £26.99 | eBay

Pair of Aluminium Solar Panel Mounting Brackets. Length 670mm. Sale Price £26.99. Brackets are bonded onto mounting surface with appropriate adhesive with the solar panel also bonded to the bracket.

www.ebay.co.uk

 

[Orion]

Rivnuts might be the answer too both the self-tapper and nut and bolt issues then?

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[Lenny HB]

Reason I would not use self-tappers, some U-Tubers self-tappers have become loose over time.

Probably used stainless steel ones, put alloy & ss together & you get galvanic corrosion that why if you use SS nuts & bolts you need to put a barrier between them & the alloy.

If you are worried about the mandral in a pop rivet rusting just punch it out.

 

[Marauder]

Thanks

 

[Doobray]

Out of interest. Did you secure the Y connectors down at all? Wondering about wind on the roof when driving

I put a couple of cable ties on the cables

 

[Doobray]

Also used Gorilla double sided gel tape on the y connector

 

[Funnymunny]

If using pop rivets on aluminium then use Monel Rivets to stop galvanic corrosion. Slightly dearer but cheaper in the long run

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[VXman]

Probably used stainless steel ones, put alloy & ss together & you get galvanic corrosion that why if you use SS nuts & bolts you need to put a barrier between them & the alloy.

By a barrier do you mean a washer? Would a rubber washer do the trick?

 

[Lenny HB]

By a barrier do you mean a washer? Would a rubber washer do the trick?

A smear of silicone grease is what I use, you could use any grease but silicon is clear and looks neater, sailors used to use Evostick on their fittings. Anything that reduces surface to surface contact but I wouldn't use a rubber washer I think the screw could work loose.

 

[Orion]

By a barrier do you mean a washer? Would a rubber washer do the trick?

I’ve used Duralac for the same purpose.

 

[VXman]

Another question - Got all my wiring sorted. Going to test it out before sticking the panels down. I'm using a NDS Suncontrol2 controller. The non Bluetooth version so info is quite basic. I know I need to link the positive pins of the 2 solar outputs to handle the wattage/amps of the 2 panels in parallel.

What I am not sure about is how I test/measure if both panels are working/contributing. I will only have a green light to say voltage is coming through and that will be the same for one or two panels. So how do I know if the 2nd panel is working (i.e. providing more watts)when it's all pugged in?

 

[Lenny HB]

Cover one panel and see how much current is going into the batteries then uncover it and the current should double, won't always be double as solar output can vary by the minute.

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[VXman]

Cover one panel and see how much current is going into the batteries then uncover it and the current should double, won't always be double as solar output can vary by the minute.

Ah - yes. Covering each panel in turn makes sense. However - double the voltage won't happen on the output of the controller above 14.4V as the controller will be limited. It would on a cloudly day I guess - if each panel was producing under 7.2 volts.

 

[Lenny HB]

Ah - yes. Covering each panel in turn makes sense. However - double the voltage won't happen on the output of the controller above 14.4V as the controller will be limited. It would on a cloudly day I guess - if each panel was producing under 7.2 volts.

I would expect to see a much higher voltage from the panels just won't be much current flowing.

 

[BouncyBoatFolk]

These will hold the panel to the frame. You can also get some caps for heads.

TechFast Hex/Washer Self Drilling Roof Screw 6.3 x 25mm | Toolstation

Self drilling screw with hex head and EPDM washers. Used for joining metal roofing sheet panels together. Salt spray tested to 1000 hours.

www.toolstation.com

I used them on my panel, they haven't backed off yet.

 

[VXman]

How much Sikaflex 522 will I need for 2 alloy amounts 67cm X 7cm? I have one 300ml cartridge. Am I likely to need more?

 

[Lenny HB]

How much Sikaflex 522 will I need for 2 alloy amounts 67cm X 7cm? I have one 300ml cartridge. Am I likely to need more?
View attachment 718456

I think you will just get away with it. Can you buy it locally so you could return a tube if unused.

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[VXman]

I think you will just get away with it. Can you buy it locally so you could return a tube if unused.

That's the problem. I can't seem to find it locally - only online. I wouldn't want to be starting the job and then running out. I think I might have to bite the bullet and splash out on a 2nd cartridge just in case. Could always sell it off on ebay if not needed I suppose

 

[BouncyBoatFolk]

That's the problem. I can't seem to find it locally - only online. I wouldn't want to be starting the job and then running out. I think I might have to bite the bullet and splash out on a 2nd cartridge just in case. Could always sell it off on ebay if not needed I suppose

Given the task, it's one of those things " you want to be looking at, and not looking for".
Mike.

 

[Doobray]

I used 2 tubes although it was Bostik 360.