Adding more solar panels (1 Viewer)

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UK Pete

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I have been upgrading my whole power system gradually as and when i can afford to
The first phase was change the two lesuire batteries for new and bigger capacity, then i upgraded the regulator to mppt capable of 300w , then today i have received two new 80w solar panels which i will fit saturday, making my total solar 280w
My question is, rather than route new cabling into the van can i cut in to the wiring on the roof for my existing 120w solar panel , this will save me loads of hassle , i just want to be clear that it is ok to do it this way, and what sort of connectors do i need to order
 

canopus

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No need to cut into the cable. Make the connection within the terminal enclosure of the existing panel. Thats assuming that the cable from your existing panel to your batteries is man enough to carry the increased load.
 

Techno

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Yes cut and use MC4 connectors and two or three way splitters. Panel JB's don't have entry glands for more than the original cables. You will need a crimping tool , connectors are cheap.
 

Techno

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This was my centre of three panels prepared for the outer two
Broken Link Removed
 

eddie

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LOL Andy, not you, the OP I knew that you would know (y)

It is that some of the wire used by dealers and converters wouldn't be up to tying a chicken, let alone adding additional panels

:eek:
 

Techno

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I rightly or wrongly assumed that Pete had installed the 120 watt panel himself :)
 

DBK

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I may be missing something here but if you plan to link the panels in series, which is best I think if you have different sized panels, make sure your controller can take the maximum voltage of all the panels added together.
 

Techno

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No he plans to parallel them on the roof rather than in the van

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UK Pete

UK Pete

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The 3 panels will be in parallel, giving the mppt 280w and 12 volts . it is a 12v 25A 300w controller so just right for this parallel set up, i think i am right here?
pete
 

eddie

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So long as the wire can handle 280 watts Did you install the cable originally? can you remember the spec? or did the dealer/manufacturer install the wire?

If so, if you can find out, I or Andy (plus many others) will easily be able to tell you if it is man (or woman lol) enough

Eddie
 

DBK

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The 3 panels will be in parallel, giving the mppt 280w and 12 volts . it is a 12v 25A 300w controller so just right for this parallel set up, i think i am right here?
pete
Again, I may be speaking out of my fundament, but if you have different sized panels in parallel is this the most efficient way of doing it as I thought the panels need an optimum voltage? Secondly, if you are connecting in parallel the wires going to the controller need to be a lot thicker than the originals probably were, ie, don't break into them on the roof. They need to be replaced.
 
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Techno

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Again, I may be speaking out of my fundament, but if you have different sized panels in parallel is this the most efficient way of doing it as I thought the panels need an optimum voltage? Secondly, if you are connecting in parallel the wires going to the controller need to be a lot thicker than the originals probably were, ie, don't break into them on the roof. They need to be replaced.
You cannot do THREE panels in series. The voltage will exceed the spec of the regulator by a long way.
 

DBK

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You cannot do THREE panels in series. The voltage will exceed the spec of the regulator by a long way.
That was my understanding too. The question I guess is should you "bodge" the installation with mismatched panels or not? By which I don't for a moment criticise the OP, more a rhetorical question.

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Techno

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Nothing wrong with different sized panels. Preferably having the same MPPV but not life or death.
 
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UK Pete

UK Pete

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Wire size going to be 6mm, i will investigate the original size wire and upgrade if necessary
pete
 

Lenny HB

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6mm Should be fine, I only used 4mm on my 2 x 100w panels the cable run was only about 5 meters. Although there will be a few percent loss, the maximum loss will occur when the panels are producing their maximum output in high summer so not worth worrying about. In the winter when they are only producing a few amps the loss will be insignificant.
 
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I wish I knew what you lot were talking about. I would love to fit solar to the van myself.

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pappajohn

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Just like a charger only sees one large battery if using odd capacity batteries in parallel, the controller will only see one 280w panel if all three are wired parallel.
 
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UK Pete

UK Pete

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How can i tell what my existing solar wire size is, the outside diameter is the same as my 6mm new cable i have, would that mean the inside is the same, cabling confuses me like you have say 20 gauge, then people talk in mm ,
 

Techno

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You need to look at it at carefully at the end or when you cut it. Just compare it with the cable you know to be 6mm.
It can be 2.5, 4 or 6. I would think it most likely to be 4
Often printed or molded into the outer sheath too
image.jpg
 
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Nigel&Debbie

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Just to let you know that one major Uk manufacturer, based in Grimsby and beginning with 'A' uses nice fancy connectors on the roof and 4mm sloar cable from the panels to their Regulator on the Sargent panel. However, they then use 1mm standard domestic cable to connect the Regulator to the actual Sargent panel - wouldn't believe it but seen it myself and had to upgrade the system. The benefit of adding a quality Regulator connected direct to batteries with quality cable and bypassing the entire Sargent unit is massive.
 

Lenny HB

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Just to let you know that one major Uk manufacturer, based in Grimsby and beginning with 'A' uses nice fancy connectors on the roof and 4mm sloar cable from the panels to their Regulator on the Sargent panel. However, they then use 1mm standard domestic cable to connect the Regulator to the actual Sargent panel - wouldn't believe it but seen it myself and had to upgrade the system. The benefit of adding a quality Regulator connected direct to batteries with quality cable and bypassing the entire Sargent unit is massive.
Even better, my mates Carthago has manufacturer installed 6mm cable so when he got his dealer to fit a panel they ignored the 6mm cables and use 1.5mm mains flex, also fitted a 5 quid regulator and only charged him £500 and you should of seen them mess they made fitting the panel with Stika. I tried to get him top complain all he did was mention the regulator so they sent him a 20 quid one which I fitted for him, also they wired it direct to the battery instead of via the CBE charger.
I did offer to fit a panel for him but as it was a new van he thought it would be better to get the dealer to do it and of course I have been taking the piss out of his installation ever since and won't let him live it down.
 
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UK Pete

UK Pete

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That was my understanding too. The question I guess is should you "bodge" the installation with mismatched panels or not? By which I don't for a moment criticise the OP, more a rhetorical question.

I certainly dont wish to bodge it, thats why i am seeking the advise from people on here, but what you have to understand is that i have already got a 120w panel the van came with, and the only size panels i can get to fit in the remaining roof spaces are 2x 80w panels ,so i have to do the best with what i got, in parallel the combined wattage seen by the controller is 280w so it will all work with reasonable efficiency, no doubt in an ideal world starting from scratch things would be different, but i think i am doing the best i can, its like adding more batteries, the best thing is to have them all beside eachother with equally wire lenths and wired in a way that draws equal power from each, however i want a total of 4 batteries so i will have to have two banks of two in different locations and do the best wiring i can under the circumstances, that will be my next question when i get the solar panels done
pete
 

eddie

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Like Andy and I have said 6mm cable will handle the additional panels so no need to disturb the thru roof set up. Just buy the correct connections compatible with what exists on the rood currently

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