Solar panel wiring help

[Legin]

Im fitting two panels 110w ea with Victron MPPT. I have some questions around wiring it up, mainly how best to keep the connections neat and weather proof.

1/ What cable size is recommended to run from the roof to the MPPT and from MPPT to battery. it looks like 2.0mm2 or maybe 2.5mm2, flat or round ?
2/ Linked to 1 Is it best to wire in series to keep the cable size down from the roof and reduce number of common connections
3/ How do I connect the MC4 to the twin cable. Looks like anything from cut and solder and shrink wrap to using some form of twin connector ?

 

[Bramco]

I used flat cable, 2.5mm from memory.

Not sure about series or parallel - I guess series may make things simpler if the Victron can take double the voltage of each panel. You should be able to connect one of the connectors from one panel to the other one if you see what I mean and that would mean less faffing around.

When I replaced the panel recently I left the connectors on that they came with and fastened connectors to the wire into the van. With those sorts of connectors, crimping is the best bet and it's worth getting the right tool for the job, or borrowing one from someone if you can.

The connectors for ours are on the van roof just behind the panel and I've used some cable ties and those stick on pads that you can fasten them through to keep everything from flapping around. The great thing about having the connectors on the roof is that when (not if) your van needs to have the roof corrosion fixed, you can take the panels off without having to mess about with the cable routing into the van.

Simon

 

[Max-Felix]

Where did you buy the kit? The supplier should provide (included with the kit or at cost) the correct cable set up complete with assembled waterproof connectors and correct gauge wire ready to go.

 

[Bramco]

Not everyone buys a kit Max-Felix. I'm assuming from the OP that Legin will be buying all the bits piecemeal to set up a bespoke system.

Simon

 

[Max-Felix]

Yes, I understood that - just saying that the supplier of the panel will usually be able to supply a loom with all the correct spec cabling and connectors assembled with professional crimpers etc and for often less £'s/hassle than trying to get the parts/tools etc yourself.

For what it's worth to the OP here is how I run mine:

https://vwcaliforniaclub.com/thread...etooth-and-phone-app.14750/page-2#post-264951

 

[Legin]

I am indeed doing this myself. I have all the tools to do it however the supplier will just give me mc4 connectors and so on if ask.
I have already bought the same wickes angle so got that right. I notice that max-felix has two seperate cables running into the grommet not something I was considering an option. I noted lots of spare cable coiled up, does this cause a large voltage drop ?
Anyway looks like series is the way for me as it simplifies the number of connections and i will think whether two seperate cables or one twin is best for me.

Bramco the way you have done it was what I was initially thinking and it seems everyone has a slightly different approach. 2.5mm2 seems a resonable choice.

 

[Max-Felix]

No issue with voltage drop as long as sufficient (ie overkill!) cross section cable is used. I wanted it long as I wanted the ability to run it up front if used in a Beach rather than a SE/Ocean.

Remember to mount some padded tape under the angle to protect the roof:

https://vwcaliforniaclub.com/thread...olar-panels-for-2017.16907/page-5#post-316046

 

[Legin]

No issue with voltage drop as long as sufficient (ie overkill!) cross section cable is used. I wanted it long as I wanted the ability to run it up front if used in a Beach rather than a SE/Ocean.

Remember to mount some padded tape under the angle to protect the roof:

https://vwcaliforniaclub.com/thread...olar-panels-for-2017.16907/page-5#post-316046

Will do on the tape. Did you add any stiffeners beyond using the angle as i see the roger ones now have some underneath at either end.

 

[Bramco]

Did you add any stiffeners beyond using the angle as i see the roger ones now have some underneath at either end.

On my replacement panel I added some stiffeners front to back on the edges (aluminium strip). It makes everything much more rigid.

I also added draft strip/tape (the kind used on doors or windows about 3/4 inch across ribbed on the non sticky side - you'll find similar in Wickes or B&Q) along the underside side to side on the aluminium as well as front to back on the panel itself where it would rest on the central bumps on the roof if you see what I mean. This also stops the panel vibrating at speed.

Also Max-Felix, if you are buying from ebay, I didn't see any cables, just the cable attached to the panel with connectors - maybe I didn't look hard enough!!

Simon

 

[Max-Felix]

No, just PU adhesive to the panel and a rivet here and there - more than strong enough IMHO.

Simon, I did not buy the solar stuff on eBay I got it all from Midsummer - I can highly recommend them in all respects of know how, supply and back up.

 

[Bramco]

Simon, I did not buy the solar stuff on eBay I got it all from Midsummer - I can highly recommend them in all respects of know how, supply and back up.

Good to know - although I hope our replacement will be good for a few years now.

Simon