- What warranties come with a solar system? What should I look out for?
Buying solar is about the same as everything else; you get what you pay for. If you buy the cheapest stuff on the market you can expect the lowest performance and unfortunately a high chance of failure.
For this exercise lets imagine you’ve checked your system and noticed that the inverter is on but it’s showing no power being produced. So you’ve checked your panels and noticed that one of them looks like waters got in and part of it has gone a milky white.
Now, the nature of 99% of residential solar systems means that if 1 panel in a string fails then the whole string can’t make any power. So you’re going to want to get that panel replaced pretty quickly! That’s when your warranty comes into play.
There are two types of warranty on a panel:
• Workmanship/Materials (also on inverters)
The workmanship/materials warranty covers the construction of the panel and would cover issues that may not have a massive effect on performance but still make it unsuitable for long term use.
An example would be if the DC connector points on the back aren’t mounted correctly and are loose. They may still allow electrical charge through but it’s not suitable for long term use.
Every panel has a performance warranty that guarantees the output of the panel for a set amount of time. These warranties vary from company to company but guarantee a certain level of output depending on how long the panel has been installed.
Generally there are two types, a step warranty or a linear warranty. If you can get it, a linear warranty is preferred and generally is only offered by higher quality panels because the company is more confident in their product.
So, under our hypothetical situation with 0% performance, due to workmanship problems we could reasonably be covered under both warranties.
This is where the difference in companies really sticks out.
What to watch out for in your warranty
To put it simply your warranty should cover the end to end repair/replacement of your faulty unit, whether it is the inverter or the panel. For our panel situation that means:
• Removal of panel
• Transport to manufacturer
• Testing of panel (if required)
• Transport back to your premises
• Testing for system working
This is one of the points where getting what you pay for is definitely true. For the mid to higher end of the price scale the warranties generally cover this whole process and most companies have a presence in Australia which helps speed up the process.
On the lower end only the testing of the panel and repair/replacement is covered. That said, testing is only covered if they find a problem with the panel, otherwise you have to pay for that as well.
That means to get your warranty on your cheap panel means you have to pay for:
Solar certified electrician to uninstall and remove panel
Shipping to manufacturer (usually in China so customs fees apply)
Possibly the testing of the panel
Shipping back to you (again customs fees)
Solar certified electrician to re-install and test panel
A quick call to customs Australia reveals that the shipping and customs charge for the two-way transport runs at about $1600 without all the other charges.
In the end it would be cheaper to just buy a new panel.
When buying solar systems check closely what the warranty action is if any component fails. On the cheaper gear the warranty could not be worth the paper it’s written on if it doesn’t cover the end to end repair/replacement process.
- How does solar save me money?
- If I install solar, what happens at night?
- If I install solar, what happens during a blackout?
All grid connected solar systems will and must disconnect from the grid during a blackout. In the case of 99.9% of residential connected solar systems that means that the solar system will shut down.
There is a very good reason for this and that is safety.
There are two reasons power to your house goes out.
• Planned network maintenance in the local area
• Unplanned system disturbance has knocked out the power
In either case there is probably going to be line workers coming to work on the powerlines not far from your house.
When they get there, because the grid has been turned off they are going to be expecting that those powerlines they are about to touch are completely dead.
However, if you’ve got a neighbourhood down the road with PV generation, that’s going to mean those lines aren’t dead. This is a very real danger for anyone working on them.
This situation where a local generator remains on even when the grid goes down is called Islanding. Australian standard 4777.3 dictates that any grid connected inverter (such as in a PV system) MUST disconnect from the grid with 2 seconds of the grid going down through some kind of anti-islanding scheme.
What’s the simplest way to disconnect your system from the grid? Shut it down.
Why can’t I just have switch which takes me off the grid but leaves my system on?
Earlier I mentioned that 99.9% of residential PV systems shut down when the grid shuts down. This is because this is the easiest way to ensure the PV system doesn’t island. You can make it such that the PV system will remain on AND you’ll be disconnected from the grid.
However, this is much more complicated, and therefore much more expensive.
Essentially there are two ways to do this.
• Always have your PV disconnected from the grid
• Add switches and rewire your home electrical configuration
Always have PV disconnected from the grid
This method involves splitting your household load between grid-connected and PV-connected loads. What this means is some appliances, for example your pool pump, are connected ONLY to your PV system. So your grid connection and PV connection are isolated from each other. This means you can still run your pool pump when the grid is off but also means you can not run it if the sun isn’t shining.
Add switches and rewire your home electrical configuration
In this instance you add a disconnect switch where you connect to the grid. This switch must operate automatically within 2 seconds of the grid going down so as to be the same as the constraints on a PV inverter.
Inside the house your electrical setup must be adjusted such that the solar system will have a pathway to inject electricity to your house even if your grid connection is cut.
Additionally the PV inverter you purchase must be setup for off-grid functionality which not all off the shelf inverters are or have the capability for.
A solar system will disconnect during a blackout for safety reasons. Shutting down is the simplest and cheapest solution to making sure the system is disconnected.
While it is possible to make it such that the solar system will not shut down during a blackout the expense and inconvenience far out weighs the benefit. This is particularly true in most areas of networks where the frequency and duration of blackouts is low.
- Can I expand my system later down the track?