Simultaneous solenoid valves

We are asked the same question again and again: How many solenoid valves can the OpenSprinkler open at the same time.

But the answer is always “it depends,” because the solenoid valves from different manufacturers have different performance values.

I got to the bottom of the matter and did some exemplary tests.

a) With the OpenSprinkler AC and the standard AC power supply

The standard AC power supply has an output of 24VAC / 1500mA = 36VA. Here is my test video:

Result: All 8 solenoid valves could be controlled with a power of 1500mA. The power supply has been used to its maximum, which also means that no other consumers may be connected at this maximum connection - otherwise “only” 7 will work at the same time.

b) With the OpenSprinkler DC and the standard DC power supply

There are two standard DC power supplies as availability varies:
One has a power of 7.5V / 4320mA and 32.4W, the other 2930mA and 22W. Here is my test video:

With a maximum consumption of approx. 850mA for all 8 solenoid valves, DC technology shows its strength: despite a lower voltage, significantly more solenoid valves can be addressed with the same power supply power due to the pulse method. With this consumption, 28 solenoid valves can be controlled mathematically - but be careful, the impulse when opening the solenoid valve generates 3 times the voltage, so 26 solenoid valves end - the OpenSprinkler can handle a maximum of 3A.

However, the following must be noted for both tests:

• The tests were carried out with Rainbird Type 100-HV solenoid valves. Solenoid valves from other manufacturers have different performance values ​​and can therefore produce different results. Always follow the manufacturer’s instructions!
• The OpenSprinkler can handle a maximum of 3A. Even a short pulse over 3A can trigger the fuse. It's better to stay at max 2.5A. The display in the OpenSprinkler shows the current consumption.
• To clarify again: This is about valves being opened AT THE SAME TIME. The ZoneExpander can be used to control up to 72 valves, which are switched one after the other.
• Please also keep in mind that the more valves are open at the same time, the water pressure will decrease accordingly.