SAJ - Inverter Reviews

About SAJ

SAJ is a Chinese producer of low cost solar inverters. Its full name is Guangzhou Sanjing Electric Co. LTD. The first word stands for Guangzhou City, which is where its headquarters are located.

In addition to solar inverters, SAJ also supplies batteries and electric pumps, but I’ll only describe their residential solar inverters here.

A Melbourne Office

SAJ has an Australian office in Melbourne. Its address is:

• 17 Silicon Pl Tullamarine VIC 3043

An Australian office is always an advantage if there is a problem with an overseas product. If you have an issue with your inverter your first port of call should be the installer you bought it from. But if they’re no longer around you can make a warranty claim from the manufacturer – provided they have an Australian office. If they don’t, then the importer is responsible for the warranty.

SAJ Solar Inverters

SAJ produces three main series of residential solar inverter:

• R5 single-phase inverters
• R6 3-phase inverters
• H2 single-phase hybrid inverters

I’d normally recommend homes with 3-phase power use a 3-phase inverter, but 3-phase properties can use single-phase inverters.

R5 Single-Phase Inverters

Capacity: These single-phase inverters range from a tiny 0.7kW up to 12kW. As few manufacturers make very small inverters, SAJ is an option for applications that require them.

MPPTs: All R5 inverters under 3kW have a single Multiple Point Power Tracker (MPPT) This means that, in normal circumstances, panels will only be able to face one direction. All R5 inverters over 3kW have two MPPTs. If you want a 3kW inverter, they make one with a single MPPT and another with two.

Efficiency: Higher capacity R5 inverters tend to have higher efficiency. Their average efficiency ranges from 96.4% to 98.3%. For a 5kW inverter it’s 98% or 98.7% depending on the model. While not bad, this isn’t exceptional for inverters like this that don’t have fans and rely on natural convection for cooling.

Operating Temperature: Their operating temperature ranges from -40° to 60°C. Inverters normally derate and reduce their maximum power output when they approach their maximum operating temperature. Their derating temperature is not given on their datasheets or in their installation manual, but I would expect them to derate from 45-60°, as SAJ’s 3-phase inverters do. Assuming this is correct, they have a suitable temperature range for Australia.

R6 3-Phase Inverters

Capacity: SAJ’s 3-phase inverters range from 3kW to 50kW, with the larger ones for commercial installations rather than residential. Not many 3kW and 4kW 3-phase inverters are on the market, so if you want a small one, SAJ is an option.

MPPTs: The number of MPPTs depends on the size and model of inverter. The MPPT number and associated capacities are:

• 2 MPPTs = 3-15kW
• 3 MPPTs = 5-10kW
• 4 MPPTs = 25-50kW

Efficiency: The datasheets for SAJ’s 3-phase inverters say their average efficiencies range from 97.8% to 98.7%. But the datasheet for their R6-(5-10kW)-S3 inverters says their maximum efficiency is 98.2% but also says its Euro efficiency figure – an average value calculated in a set way – is 98.7%. Since its average value can’t be higher than its maximum value they have clearly made a mistake and the real efficiency of these inverters is a mystery.

Operating Temperature: The operating temperature is given as -40 to 60 degrees. But the 3-phase inverters will derate at temperatures over 45 degrees. This means between 45 and 60 degrees its maximum power output will decrease. While it’s not good that they derate, this temperature range is still suitable for Australian conditions.

H2 Single-Phase Hybrid Inverters

The H2 series a high-voltage hybrid inverter, with output power output ranges from 3-6kW. 

The H2 series provides 3 different modes of use, offers backup (UPS switch time ≤ 10ms), supports load monitoring and zero export features. The maximum string input current is 16A. 

These units measure 385.5 x 499.0 x 193.5mm and weigh 17.6 kilograms. They have an operating temperature range of -25°C to +60°C.

Oversizing

It’s normally a good idea to have solar panels with a total capacity greater than the inverter’s capacity. This is referred to as “oversizing”. In practice, most rooftop installations can oversize up to 133%. But in some circumstances, it may be possible to oversize up to what the inverter can handle. Some SAJ inverters can only be oversized up to around 133% but most can accept up to 150%. The exact figure will depend on the specific model.

Installation Location

According to their installation manuals, SAJ inverters must be installed out of direct sunlight. But they don’t say they have to be located out of direct rain.

10 Year Warranty

SAJ’s R5 and R6 series of inverters come with 10-year warranties. This is a standard period for solar inverters these days. The warranty can be extended at an extra cost to 15 or 20 years.

A Low-Cost Inverter

SAJ inverters are low-cost, so I don’t think it’s reasonable to expect them to be as reliable as higher-end inverters. But some may consider a greater chance of failure a reasonable trade-off against their low price. But note the labour cost involved in replacing an inverter can be high.

Currently, SAJ aren’t among the inverter brands we recommend because we don’t have good information on their long-term reliability. If you want to see a chart of the inverters we do recommend, you can check out our Solar 101 Guide.

If you have a SAJ inverter and would like to leave a review, the information will be appreciated.