Simultaneous solenoid valves

We are asked the same question over and over again: how many solenoid valves can it handle 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 tests as an example.

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

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

Result: All 8 solenoid valves could be controlled with the power of 1500mA. The power pack was maxed out, but this also means that no other consumers may be switched on with this maximum wiring - otherwise “only” 7 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 an output 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, the DC technology shows its strength: Despite the lower voltage, significantly more solenoid valves can be addressed with the same power pack performance due to the impulse process. Arithmetically, 28 solenoid valves can be controlled with this consumption – but be careful, the impulse when the solenoid valve opens generates three times the voltage, so 3 solenoid valves end – that OpenSprinkler can take max 3A.

For both tests, however, the following must be observed:

• The tests were conducted with Rainbird Type 100-HV solenoid valves. Solenoid valves from other manufacturers have different performance values ​​and can therefore produce different results. Always observe the manufacturer's information!
• The OpenSprinkler can take max 3A. Even a short impulse over 3A can trigger the fuse. Better to stay at max 2,5A. The ad in OpenSprinkler shows the current consumption.
• Again to clarify: We are talking here about SIMULTANEOUSLY opened valves. The ZoneExpander can control up to 72 valves, which are switched one after the other.
• Please also consider that the water pressure decreases accordingly, the more valves are open at the same time.