DC or AC?

Which is better, OpenSprinkler in the DC or the AC version?

First you have to explain where the differences are. DC stands for “Direct Current” and means direct voltage while AC stands for “Alternate Current” and alternating voltage.

A distinction is made here between two different power supplies. But which one is “better”?

This question cannot be answered so easily. The 24VAC technology is quite old, but particularly robust. But you also need a power supply, which takes up a lot of space. And then there is the problem of “humming”, i.e. the transformer makes humming noises. The big advantage, however, is that all irrigation technology from the major manufacturers works with 24VAC. This means that an existing computer with 24VAC control, which does not yet have WiFi or an Internet connection, can be easily replaced with the OpenSprinkler AC.

DC technology, on the other hand, is very new. We always deliver a 7.5VDC power supply with the OpenSprinkler DC, as this is difficult to find on the open market. In fact, the OpenSprinkler DC can be operated from 5VDC to 12VDC - the necessary voltage to open the valves is generated internally with a booster. With 7.5V we even have the optimal ratio between internal and external resistance, so that the power consumption in this variant is particularly low. So the DC version is actually the better one when setting up a new system.

If you want to use OpenSprinkler to control additional components, such as lights or pumps, you need a relay. But be careful, while you can use normal 24VAC relays for OpenSprinkler AC, you have to use 3-32VDC SOLID CONDUCTOR RELAYS for the DC. If you use a 12VDC power supply on the OpenSprinkler DC, you can also use normal 12VDC relays. It is important that the 12VDC + from the power supply is connected directly to the relay +, the relay - is then connected to the desired port 1-8 on the OS DC - so do not connect the relay to COM, but always connect the solenoid valves to COM. This bypasses the booster.

Solid state relays do not have any mechanics like traditional relays, so they are more reliable and durable.

Another interesting feature of the DC variant is that the solenoid valves no longer “hum”, but only “click” when switched on and off.

Both variants can easily switch all types of 24VAC solenoid valves. Yes, you read that right! The 24VAC solenoid valves also work with the DC!

With both the OpenSprinkler AC and the DC you can order the “standard power supply” when ordering. The AC is the 24VAC 1A, the DC is the 7.5VDC 2.93A plug-in power supply. Both are available for an additional charge of 10 EUR. Individually, these cost almost twice as much.

Yes, really: with the OpenSprinkler DC you can easily 24VAC solenoid valves use! Read the history of DC technology here (English).

Conclusion: Use OpenSprinkler AC to replace an existing computer, OpenSprinkler DC for new installations.