Adding Solar Panels to Existing System

[richeirich]

Hello!

I'm asking for some advice on how I would go about adding 3 or 4 solar panels to my existing system.

Currently I have:

11 solar panels mounted on a pitched roof
Module Type: Kinve 250-60M
Inverter: SunnyBoy HF2500
Installed Capacity: 2.75 kWp (11 panels - 250W each)
Roof Orientation: South

I would ideally like to do this work myself. It is hard to get any solar installer to do this sort of work, as they want to replace the system rather than add to someone else's, and then it becomes prohibitively expensive.

As far as I can work out, since it is a string system, my thoughts are to:
1. Switch off the AC isolator
2. Switch off the DC isolator
3. Unplug the cables from the isolator inputs to the DC isolators
4. Fix mounting brackets to the adjoined, smaller roof
5. Somehow disconnect one of the connections on the end of one of the rows of the existing system, and connect it up to a new string of 3 panels (which is on the adjoined but much smaller roof)
6. Connect the end of the 3 new panels to the inverter, or back into the original 11.

Stages 1-4 seem pretty clear to me. I understand that I have to keep the wattage of any new panels exactly the same as the old. And I understand that I'll need a new inverter (I was thinking a SunnyBoy 3000).

But could someone explain like I'm 5, how to connect up the new solar panels, to the existing system? Do I need female and male couplers and perhaps some solar cable also?

Any advice much appreciated!! Thanks

 

[richeirich]

This is an image of the location if that helps!

 

[Notch7]

Unfortunately I doubt you will get anybody to help as what you propose probably needs requires DNO notification and building regs cert.

Id guess that means MCS qualified and suitable electricians quals

Solar panels can feed power to the grid, if they are installed incorrectly power could be sent down the grid whilst it is turned off for repairs

 

[ericmark]

My inverter and I would think most are similar, has the panels in two groups, so that each group can supply a different amount of power. At the moment,

they show if your inverter has two or more inputs, you could in theory add more panels, but mine the two inputs already used, and could not combine without overloading the inverter.

So to add to my own system, I would need a second inverter, the instructions do show

having multi-inverters, so I am sure I could have a second inverter fitted, but solar panels have progressed over time, so the idea of adding to existing would only work if the panels in use are still available, and the new roof is getting same light as the old roof, and that seems unlikely.

Your max power it seems is 3450 watts. As you can see today, my panels are exceeds what your inverter can handle.

So it seems in essence you will be starting from scratch, new inverter, new applications to DNO etc. And so even if you worked for an installer and have all the knowledge required, to get yourself registered to do the work, is really a non-starter.

Also, I see no reference to battery, in the main my solar pays for its self due to the battery, and to be frank is you can understand what this manual is telling you to do you're doing better than me. I have read my own manual, and still had to ask the installer for help to alter settings. And in turn my installer has needed to contact the manufacturers for help, even with a degree in electrical engineering I would not attempt to fit my own grid tie solar panels. Even if allowed to.

 

[Murdochcat]

A word of warning.

The DC current from solar panels can give you a very nasty shock

Why do you want to add more ?

 

[Murdochcat]

Solar panels can feed power to the grid, if they are installed incorrectly power could be sent down the grid whilst it is turned off for repairs

Not sure I agree with this.

All solar panels can and almost certainly do export to the grid

 

[StephenStephen]

Why do you think you need a new inverter?

 

[ajstoneservices]

If you are receiving the feed in tariff on the existing system you could end up in a world of pain with both Ofgem and your fit provider if you add panels to the existing system.

 

[Why Not Indeed]

If you're replacing the inverter, get one that can take two strings. Then you don't have to worry about messing with the existing string.

Why do you think you need a new inverter?

A quick google suggests his existing panels are already maxing his existing inverter.

 

[StephenStephen]

If you're replacing the inverter, get one that can take two strings. Then you don't have to worry about messing with the existing string.



A quick google suggests his existing panels are already maxing his existing inverter.

In many situations it can be more worthwhile to have the ratio of inverter output to max panel output well below 1:1