Solar Panels Cabled In Parallel

[poindexter]

Hey forum, just interested to know if what I have in mind would be considered normal or not.

I have decided to cable up my solar panels in parallel. I have x2 175w panels and x3 50w panels. The 175's will have a charge controller and the 50's will have a charge controller.

Cabling these in parallel means adding x5 entry points onto the roof (one entry point per panel), unless I merge the 175s and the 50s into the same circuit on top of the roof which would result in having only 2 entry points on the roof.

The advantages of having the 5 entry points (one per solar panel) are that I could switch them on/off individually which would allow for very easy troubleshooting and replacement if ever the need arose.

The disadvantages of having 2 entry points (one for 50's and one for the 175's) are that it would be difficult to tell if a panel became non functional and which one it was. Although fewer holes in the roof would be preferred.

Just wondering what others have seen done in a situation where there are this number of solar panels on the roof cabled in parallel?

5 entry points seems a lot to me. But from a functional perspective would give me the best result.

Interesting in hearing your thoughts...

Thanks!

 

[monzer]

If you have 2 controllers would that not just mean 2 holes in the roof? Even 1 if they are close to each other?

I'd use 2>1 connectors on the roof instead of running them down individually. Even if it does mean more bother troubleshooting.

 

[Two on Tour]

On a previous solar panel setup I had, I used a waterproof adaptable box and fitted M12 waterproof glands into one side. With the box silicone to your roof then you can bring all of your cables into your van through one hole in your roof.
I had a short length of solar cable protruding out of each gland connected to a MC4 connectors to connect to the panels.
I could then connect and dis-connect whatever panel on the roof I wanted while keeping all cabling to my MPPT controllers in-siti.
You could do this with however many panels you wanted and it will give you some scope to add more panel if needed by adding more glands or change out the panels you have in the future.

 

[Reallyretired]

Anything going wrong with a solar panel is very rare (unless flexible ones). I'd prefer a unlikely need to get on the roof to investigate individual panels rather than turning your roof into a colander.

 

[Lenny HB]

The disadvantages of having 2 entry points (one for 50's and one for the 175's) are that it would be difficult to tell if a panel became non functional and which one it was. Although fewer holes in the roof would be preferred.

Easy to fault find you cover the panels with cardboard or a blanket in turn, easy to measure the output from each one that way.

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[Raul]

I have 4 10mm glands that takes 6mm double insulated solar cable. The glands fitted in the holes predrilled for the roof rack, I just removed the painted tape. After I run the cable trough the glands, I filed them with CT1, and a smear on the rubber gasket mating to the roof surface. So far four frosty winters and glands hold well. That’s 4 solar cables up, 2 going to each panel. You can use Y branch connectors to minimise the cable pairs.

 

[autorouter]

I have decided to cable up my solar panels in parallel. I have x2 175w panels and x3 50w panels. The 175's will have a charge controller and the 50's will have a charge controller.

Cabling these in parallel means adding x5 entry points onto the roof (one entry point per panel), unless I merge the 175s and the 50s into the same circuit on top of the roof which would result in having only 2 entry points on the roof.

Solar panels usually have a pos and neg wire with an MC4 connector on each. MC4 connectors are weatherproof, and can be safely left on the roof in all weathers. You can get 2-to-1 and 3-to-1 MC4 connectors to parallel them together. Make sure the wire is beefy enough to minimise the voltage drop - parallel connections result in higher amps.

Pair of MC4-Compatible T-Branch Solar Connectors (Enclosed Locking Tabs)

Pair of MC4-compatible T-Branch solar connectors. Industry-standard method. Ideal for connecting 2 solar panels in parallel before connecting to a solar controller.

www.12voltplanet.co.uk

Pair of MC4-Compatible 3-To-1 Solar Connectors

Pair of MC4-Compatible 3-To-1 solar connectors. Industry-standard method. Ideal for connecting 3 solar panels in parallel before connecting to a solar controller.

www.12voltplanet.co.uk

 

[Hoovie]

I can see a value in being able to change the configuration of panels and on my Camper with 4 panels I tried them in Parallel, in Series, and a Parallel/Series combo. But I did all the changes on the roof, not inside the van. There is no need to bring each panel cable pair in individually through the roof. When I added another pair of smaller panels, I added them to the array without adding extra roof holes

Hey forum, just interested to know if what I have in mind would be considered normal or not.

I have decided to cable up my solar panels in parallel. I have x2 175w panels and x3 50w panels. The 175's will have a charge controller and the 50's will have a charge controller.

Cabling these in parallel means adding x5 entry points onto the roof (one entry point per panel), unless I merge the 175s and the 50s into the same circuit on top of the roof which would result in having only 2 entry points on the roof.

The advantages of having the 5 entry points (one per solar panel) are that I could switch them on/off individually which would allow for very easy troubleshooting and replacement if ever the need arose.

The disadvantages of having 2 entry points (one for 50's and one for the 175's) are that it would be difficult to tell if a panel became non functional and which one it was. Although fewer holes in the roof would be preferred.

Just wondering what others have seen done in a situation where there are this number of solar panels on the roof cabled in parallel?

5 entry points seems a lot to me. But from a functional perspective would give me the best result.

Interesting in hearing your thoughts...

Thanks!

I would just have two pairs coming in - one for the 175Ws and one for the 50Ws.
THen on the roof, you can decide if you want the 175Ws in parallel or series, and same for the 3 50W panels.

 

[poindexter]

Thanks for the advice, really appreciate that it helps a lot. I'll just put the two cable entry on the roof Also thanks for sharing the links to the adaptors.

 

[poindexter]

I had to remove two of my 175w flexible panels as I installed them wrong. They were sikaflex'd down to the van roof. They took a right battering in the process and I assumed they were probably knackered. In fact I submitted to the fact that they would be knackered when removing them and just aggressively removed them.

I tested them today against the new ones that I got.

Would you believe it.... They are just fine!!!!!! Those flexible panels can take a beating. I am now not concerned about them going wrong.

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