Frequently Asked Questions

Questions and Answers about SunBrush® MOBILE PV Systems Cleaning

Q. What specs on the tractor are vital, weight?

A. The suitability of the tractor is determined by the width and weight. Working on a narrow based tractor, 3.5T will generally be capable of supporting the 5m brush.

Q. What strength is the steel that the frame is made of?

A. Very Solid (TBC)

Q. Are there brackets mounted to keep firm in transport?

A. You will see in the image a bar that attaches from the end of the brush end to the rear implement. There is also following requirements for transport. It is recommended that you do not exceed 4kmh without securing the brush.

Brush stowed to the transport position
A locking pin on the small hydraulic cylinder
Sling between long hydraulic cylinder
Brush is to secured with a strap to the boom
Bar secured from the brush end to the rear implement

Annotated images of securing straps and slings for transporting the PV System cleaning tractor

Q. What is the expected life span of the brush?

A. Can expect to clean approximately 200MW before the brush bristles will need to be replaced. Replacement depends bristle length. (replacement @260mm in diameter)

Q. What is the cost of a replacement brush?

A. Replacement brush is ~$2700.00 for the 3m brush and $3700.00 for the 5m brush. This is for the bristles only.

Q. What is required to change a 3 metre brush to a 5 metre?

A. When purchasing a brush it is important to note what size brush you wish to operate in the future. A 3m brush can be removed and a 5m brush added as long as the tractor is suitable. The 5m brush assembly costs ~$12,500.00. If you are ordering a 5m brush, it is important to note that you intend to operate this with 3 meter brush to ensure it comes fitted with the Twin Adaptor Arm.

Q. What is the additive that needs to be put in, .5 to 1l per 1000 litres, what is the cost?

A. Additive is determined by the hardness of the water. We recommend that this is tested onsite. Test strips can be used. Water hardness should be no more than 180ppm.

table water hardness and PV cleaning additive

Hardness ppm (see figures below)
Additive amount (see figures below)

Soft: 0 to 60 ppm
125ml per 1000Lt

Moderate: 61 to 120 ppm
500ml per 1000Lt

Hard: 121 to 180 ppm
1000ml per 1000Lt

Very Hard
more than 180 ppm

Additive cost is $786.00 for 25 liters.

Q. Water usage is around 1000l per hour, is that right?

A. Please note that Sunbrush is capable of cleaning without water and has been tested THU tested. The water usage will depend on the state of the modules and the speed that you are cleaning at. Generally it will consume anywhere between 0.8 – 1lt per 2m panel. I have attached a spread sheet that can assist in calculate cleaning time and water.

Download PDF