How expensive is a cheap solar inverter

4 years ago, a Mr Jones, decided to get solar panels installed on his roof hence contacted a few solar companies for quotations.

The prices of the 3kW system ranged from $2,500 to $4,000.

Now Mr Jones is a confused man with the different pricing and all companies claiming to have the best quality product. The clear winner was the cheapest price (of course!!) and upon enquiring, the salesman assured that this was their biggest seller, the price is cheaper because the solar inverter is not as expensive as the European made inverters but gave assurance that its performance is the same and it came with a 10 year warranty.

So in 2012, Mr Jones brought a 3kW system for $2,500 and thought he saved up to $1,500.

Late 2015, Mr Jones contacted me regarding his solar PV system (a friend recommended him to me). He mentioned that his system stopped working 1 year ago and the solar company who sold the system is out of business now, and he has no contact details of the installer.

To help Mr Jones, I visited the site with my electrician who checked on the system and later sent a repair quotation to him. Mr Jones was shocked with the repair cost. It was a crazy $3,400.

Well at this price, Mr Jones could purchase a brand new 2kW-3kW system but the existing faulty system needs to remain on the roof (STC t & c’s).

Of course Mr Jones wanted an explanation on why the repair cost was so high because his initial understanding was that only the inverter had to be changed.

Well, the inverter manufacturer is also no longer in business now so the 10 year inverter product warranty is of no use. The same make and model of the transformer based inverter cannot be sourced so another brand inverter needs to be installed.

Some key points during the inspections were;

The inverter is OFF, possibly component failure and would not switch ON with DC power supply;
The solar panel string voltage (open circuit) was in the acceptable range (brand of solar panel is a reputable manufacturer) so no panel fault identified;
The installation quality was very poor with cable management and all the panel leads and string cables were loose and touching the roof;
This install was done before the AS5033.2012 Standards was implemented;

The following was the cost breakdown;

$1,400 is the inverter cost – this is a European made inverter from a manufacturer that is top 3 in the global market.

$200 is for new DC isolators next to the inverter and on the roof, this system was installed before the AS5033.2012 was released hence there was no DC Isolator on the roof and the disconnectors next to the inverter was the polarised circuit breakers which cannot be used under the new standard.

$300 is for the heavy duty conduit under the roof. This requirement was not mandatory before the AS5033.2012 standards release.

$500 for the new mounting system on the roof. The electrician has to tidy up the loose solar panel cable leads hence needs to unbolt the clamps to lift the panels to manage the cables. Because the bolts & nuts of the clamps have aged, there is corrosion and a risk that it will be hard to unscrew the nuts from the bolts, and once unscrewed, the T-bolt thread and the nuts can be damaged. It’s hard to find new matching t-bolts and still have the mounting system compliant with AS1170 wind loading as the mounting system initially used does not have a brand labels.

Overall the electrician has to complete repair works and take ownership of the whole install hence becomes responsible for the whole system.

Interesting Dilemma!!!

Well, for the records, Mr Jones chose to pay the $3,400 and get the repair done instead of purchasing another system.

In trying to save $1,500 by compromising on the quality of the system, he ended up spending a total of $5,900 for a 3kW system.