solar cable and waterproof junction box

[mfw]

Slowly buying bits have bought a waterproof screw down lid multi junction box which has a pipe that goes through roof to allow additional cables to go through without having to drill more holes for additional panels or anything.

So solar 4mm pv cable comes as either a single double lead or individual leads only want to use 1 waterproof cable joint can i put 2 single cables in 1 joint ( tightened up should compress around cables ) or single cable with dual leads inside

So is 1 type of cable better than the other really want to keep it down to 1 waterproof gland

 

[DBK]

I'm not sure what you are describing. This is the box I fitted to combine the output of two panels.

 

[funflair]

The gland will be more watertight if you use one cable to one gland, if its twin core cable OK but usually solar is single.

So 3 panels = 6 cables

Martin

 

[mfw]

This is the gland i bought for the ease of adding more cables if req'd the tube fixes within casing to enable additional wires to be fed through and box is stuck on roof ( sikaflex or similar ) hole size in roof is about 30mm

The solar cable is similar price would rather of gone 2 singles but if peoples thoughts are it wont seal properly then i will get the outdoor double solar cable

Not sure if pic has come through but they are on ebay varying prices from £15



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ROOF MULTIPLE CABLE ENTRY GLAND SOLAR SATELLITE AERIAL accepts 5 dome top glands


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[funflair]

If the cable is round it will be OK and it doesn't matter if the cable is "twin" as in +ve and -ve in one circular sheath so one gland or "single" as in one +ve and one -ve so two glands, But make sure the glands are sized for the cable.

And no the image did not show.

Martin

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[Lenny HB]

I coupled my cables up under one of the panels on the roof using MC4 connectors then there was only the 2 cables to feed into a standard cable inlet.

 

[EuroTrotters]

MC4 connectors are the best way to go. If in order to do this you have to use connectors, might be best to avoid the coc block types in your photo.

If you do use them, I would use loctite 248 or similar and for braided cable, ferrules crimped at the end

 

[mfw]

So 4mm pv cable with dual wires cable separated near solar panel enough to fit mc4 connectors and that would work then

 

[funflair]

Have you got the panel? what cable comes on the panel? I would be looking for the minimum number of plugs and connections on the roof, if the cable can run straight from the panel to inside the van via a suitable gland/glands that would be my choice.

You will see in my photo post no 3 that the three panels I fitted have 6 cables through properly sized glands, the fitting to the left of the pic is the original panel with flat/twin cable "bodged" into a round gland and then sikaflex'd, I have no doubt that both work OK.

How many panels are you fitting.

Martin

 

[mfw]

Have you got the panel? what cable comes on the panel? I would be looking for the minimum number of plugs and connections on the roof, if the cable can run straight from the panel to inside the van via a suitable gland/glands that would be my choice.

You will see in my photo post no 3 that the three panels I fitted have 6 cables through properly sized glands, the fitting to the left of the pic is the original panel with flat/twin cable "bodged" into a round gland and then sikaflex'd, I have no doubt that both work OK.

How many panels are you fitting.

Martin

The panel i am looking at is the complusenergy 160w panel seem good value and very similar to phototronic universe panels if i spelt it right but going with single panel at moment

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[Lenny HB]

If you are only fitting one panel just buy a male to female extension lead twice the length you need and cut in half. The MC4 connectors will plug straight into the connectors on the panel.

 

[DBK]

I think I understand now. The panel may well come with its own cable. If it does, use that. If it doesn't, buy a twin core cable - that's a round cable with two wires running through it - and connect with that, using glands the correct size. If you plan to add more panels later then I would connect them as Lenny has shown. My bodge job was done because the existing panel was on a very short cable and lengthening it wasn't easy.

 

[funflair]

The panel i am looking at is the complusenergy 160w panel seem good value and very similar to phototronic universe panels if i spelt it right but going with single panel at moment

The complies energy will come with 2x 4.0mm cables 900mm long and it doesn’t say but the picture shows connectors as well which will be Mc4.

Martin

 

[mfw]

If you are only fitting one panel just buy a male to female extension lead twice the length you need and cut in half. The MC4 connectors will plug straight into the connectors on the panel.

That is what i was going to do but a lot of extension cables come as 2 separate wires although you can get single cable dual wire but i have not found it with connectors on

Was really hoping to only use 1 gland in box ( it has 3 waterproof connector spaces ) you can drill more if req'd at moment the 1 supplied gland is too large for a single wire i would of thought ( rubber gland 8mm across )

 

[mfw]

Been looking around sunstore solar do kits and they supply them with single cable dual core wire to connect mc4 connectors to so are the mc4 connectors waterproof once connected

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[Lenny HB]

MC4 are fully waterproof I've used them for years never had any problems with them.
I'm not a fan of twin cables going through the roof I've seen cases of water running down the sheath it is rare but can happen. If using twin cable where cables exit the sheath put some adhesive lined heat shrink sleeving and while it is hot put some pressure with pliers on the sleeving between the cables to make a waterproof seal.

 

[Margaritaman]

The gland will be more watertight if you use one cable to one gland, if its twin core cable OK but usually solar is single.

So 3 panels = 6 cables


View attachment 199517

Martin

Just interested how you combined the six solar cables together inside you motorhome Martin. Thanks in advance.

Chris

 

[funflair]

Just interested how you combined the six solar cables together inside you motorhome Martin. Thanks in advance.

Chris

A big block connector 3 x 4mm into 1 x 6mm and then to the controller.

Martin

 

[Margaritaman]

A big block connector 3 x 4mm into 1 x 6mm and then to the controller.

Martin

Thanks Martin!

 

[dpsuk999]

I'm not sure what you are describing. This is the box I fitted to combine the output of two panels.

View attachment 199514

I don’t quite understand the wiring in your box, assuming the two black cables at the top of the picture are from your solar panels and assuming blue is negative and brown positive, you have connected the two negatives from solar panels together in a loop then taken the positive from one panel (connected to red cable and the positive from the other panel and connected it to black cable) Am I missing something? Sorry I know there are a lot of assumptions above but wiring in parallel you simply join both negatives from solar panels together and take one feed from that (negative) and same with positives, obviously in series you join the negative from one panel to positive of the other which leaves you a positive from one panel and negative from the other to your solar controller.

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[funflair]

I don’t quite understand the wiring in your box, assuming the two black cables at the top of the picture are from your solar panels and assuming blue is negative and brown positive, you have connected the two negatives from solar panels together in a loop then taken the positive from one panel (connected to red cable and the positive from the other panel and connected it to black cable) Am I missing something? Sorry I know there are a lot of assumptions above but wiring in parallel you simply join both negatives from solar panels together and take one feed from that (negative) and same with positives, obviously in series you join the negative from one panel to positive of the other which leaves you a positive from one panel and negative from the other to your solar controller.

If I am allowed a guess I would say that @DBK is wiring in a second panel in series via the white flexi, the twin core down the conduit being the original wiring, but I could be wrong "again".

I think you can see that the cable was a bit tight and he has pulled a tad more from the conduit gland, it also explains why its all connected to one side of the box.

Martin

 

[DBK]

If I am allowed a guess I would say that @DBK is wiring in a second panel in series via the white flexi, the twin core down the conduit being the original wiring, but I could be wrong "again".

I think you can see that the cable was a bit tight and he has pulled a tad more from the conduit gland, it also explains why its all connected to one side of the box.

Martin

Yes, spot on. Victron recommended wiring them in series anyway but the existing cable was a bit on the thin side I felt, so series connection seemed the way to go - higher voltage but lower current.

 

[funflair]

Yes, spot on. Victron recommended wiring them in series anyway but the existing cable was a bit on the thin side I felt, so series connection seemed the way to go - higher voltage but lower current.

I didn't think you would have got it that wrong, but made me get the pen and paper out all the same.

Martin

 

[mfw]

I don’t quite understand the wiring in your box, assuming the two black cables at the top of the picture are from your solar panels and assuming blue is negative and brown positive, you have connected the two negatives from solar panels together in a loop then taken the positive from one panel (connected to red cable and the positive from the other panel and connected it to black cable) Am I missing something? Sorry I know there are a lot of assumptions above but wiring in parallel you simply join both negatives from solar panels together and take one feed from that (negative) and same with positives, obviously in series you join the negative from one panel to positive of the other which leaves you a positive from one panel and negative from the other to your solar controller.

I think i see what you mean then incoming red and black should connect to brown and blue

incoming solar wire loop should connect brown on 1 and blue on other purely for looping panels together

 

[mfw]

I think i see what you mean then incoming red and black should connect to brown and blue

incoming solar wire loop should connect brown on 1 and blue on other purely for looping panels together

No still got it wrong i think hate electrics think

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[dpsuk999]

Ah so the white conduit is one solar panel wire and the top black right hand side is the other solar panel and the top left black wire goes to the solar controller wired in series?

 

[Lenny HB]

I don’t quite understand the wiring in your box, assuming the two black cables at the top of the picture are from your solar panels and assuming blue is negative and brown positive, you have connected the two negatives from solar panels together in a loop then taken the positive from one panel (connected to red cable and the positive from the other panel and connected it to black cable) Am I missing something? Sorry I know there are a lot of assumptions above but wiring in parallel you simply join both negatives from solar panels together and take one feed from that (negative) and same with positives, obviously in series you join the negative from one panel to positive of the other which leaves you a positive from one panel and negative from the other to your solar controller.

They are wired in series, it is slightly more efficen but you must have a regulator that can handle the higher voltage. The disadvantage is if one panel gets any shade you loose the output from both panels, with parallel wiring if one panel is in shade you still get the output from the other panel.

 

[DBK]

Ah so the white conduit is one solar panel wire and the top black right hand side is the other solar panel and the top left black wire goes to the solar controller wired in series?

Yes, sorry. The new panel came with the cables and the plastic conduit. If you are using a twin conductor cable I guess you don't need a bit of conduit but the wires were separate so it does make things a bit neater.
The black cable was the original which I cut into. I managed to pull a bit more out of the gland where it goes into the van as Lenny so acutely observed. Ideally I would have liked to have replaced all the cabling to the controller but access wasn't possible without ripping out the headlining.

 

[Compactliner]

A big block connector 3 x 4mm into 1 x 6mm and then to the controller.

Martin

Martin, do you mean something like this?...one block for positive and one for negative.

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Are your panels in parallel? Do you (or anyone else) fit diodes?
I got some info back from Photonic Universe who suggested I fit (blocking) diodes to the positive side of the two extra 100w panels I'm considering fitting (in parallel).
A Google seemed to suggest blocking diodes were for series installs and bypass diodes were for parallel...hence confusion.
Many thanks.

 

[mitzimad]

mine is similar to dbks set up but the wires through the roof go straight down so the box is glued down immediately above the entry point

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