DIY grid-connect solar systems

Grid-connected solar power systems are ordinarily fitted by certified installers and with good reason - the wiring requires a qualified electrician and MCS accreditation is needed to receive the new feed-in tariff.

However, if you are interested in a smaller system is now possible to install it yourself thanks to a neat piece of kit, the Mastervolt Soladin grid-tie inverter

Like all grid-tie inverters, this device converts the low-voltage DC power from your panels to 240AC for household use. The beauty of this model is its simplicity. Just connect the panels to the Soladin using industry standard Multi Connect 4mm plugs (supplied in our DIY kits), plug the Soladin into any household socket and away you go!

The Soladin inverter can handle between 160W and 700W of panels. If you would like a larger system, then just use two Soladins - they will work quite happy in parallel.

Benefit and drawbacks of DIY

DIY installation has several benefits - you save money on installation costs, you can choose exactly the size of the system and how when and where it is installed. You can start small and build up the system when time and money allows.

The main drawback of DIY installation is that you won't qualify for the feed-in tariffs. You will still benefit from free electricity while the sun is shining, up to the power being generated and you will still be helping the environment, but unfortunately you won't be paid as much for it!

Choosing panels

Each Soladin unit requires between 40V and 125V DC input voltage and between 160W and 700W of solar panel capacity. For 12V panels such as our XM100 or XM120 modules, four to seven panels are needed. If you are using the larger 24V panels such as our 48 cell Powerglaz series, you will need two to four panels.

Panels can easily be added in the future when funds allow, but they should be of the same size and type, and should not exceed 700W or 125V total per Soladin.

Installing your own system

The most difficult part of the job is mounting the panels. They need to be facing south at around 45 degrees (in UK) in a location that won't be overshadowed. This often means a pitched roof of the house, meaning that you will be working at height to install them and great care is required for your safety.

Of course solar panels will work just as well on a flat roof, a shed or on the ground, all of which are a lot less hazardous places to work!

Note for UK installers: unless your house is listed, or you live in a conservation area, planning permission for roof-mounted panels is not required. For panels mounted on the ground or on a shed, permission is never required.

Commercial mounting systems are available but they are expensive and not necessarily appropriate to the DIY approach. We are currently working on sourcing simple low-cost mounting hardware, but all that is really required is to install two parallel horizontal bars, one higher than the other. The panels can then be screwed or bolted onto these support bars.

If this seems like a daunting prospect, then it may be worth contacting a local builder for assistance.

Once the panels are installed, they are connected together in series. Connect the positive contact of panel 1 to the negative of panel 2, the positive of panel 2 to the negative of panel 3 etc. Many panels including our Powerglaz range use Multi-Connect 4mm plugs which are waterproof, tough and impossible to connect the wrong way around.

Longer cables are then connected to the negative contact of panel 1 and the positive contact of the last panel. These cables need to be run to where the Soladin inverter is mounted.

The positive cable should include a fuse appropriate for the short circuit current of the panels you are using, which should be no more than 10A.

WARNING: DC voltage of up to 125V can be present in these two leads. Take great care not to short circuit them or to touch the conductors. Ready-made leads with pre-fitted Multi-Contact connectors are strongly recommended for safety.

Finally the Soladin is plugged into any household socket. Generation will start immediately (if it is not dark) and the LED on the Soladin will show you the system status (see manual).

The system in use

When the system is generating, any electricity you use in the house up to and including the amount being generated will come from the Soladin, will not show on your electricity meter and will be free.

If you use more than you generate, the difference comes from the grid at the normal rates.

When you are generating spare power you are not using, this will be fed back into the grid for others to use. Although it is possible to have a two-way meter fitted to measure this and receive income from the electricty company, in practice the rates are very low and the installation cost high, it is unlikely to be economic.

• Introduction
• Request an estimate
• Learn about solar feed in tariffs
• Grid-connect solar financial calculator
• Is my house suitable for solar PV?
• Learn about the Microgeneration Certification Scheme
• Find out about our installation service
• See an example of an installation
• Frequently Asked Questions