Which is better, OpenSprinkler in the DC or in the AC version?
First of all, we need to explain what the differences are here. DC stands for ‘Direct Current’ and means direct voltage, while AC stands for ‘Alternate Current’ and alternating voltage.
So there are two different power supplies here. But which one is ‘better’?
This question is not so easy to answer. The 24VAC technology is quite old, but particularly robust. However, it also requires a power supply unit, 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 WLAN and Internet connection, for example, can easily be replaced by the OpenSprinkler AC.
The DC technology, on the other hand, is very new. We always supply a 7.5VDC power supply unit 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 – a booster is used internally to generate the voltage required to open the valves. At 7.5V, we even have the optimum ratio between internal and external resistance, so that the power consumption in this variant is particularly low. This means that the DC variant is actually the better option when setting up a new system.
If you want to control additional components such as lights or pumps with OpenSprinkler, you need a relay. But beware, while you can use normal 24VAC relays for OpenSprinkler AC, you have to use 3-32VDC SEMI-RELAYS for the DC. If you use a 12VDC power supply unit on the OpenSprinkler DC, you can also use normal 12VDC relays. It is important that the 12VDC + from the power supply unit is connected directly to the relay +, the relay – is then connected to the desired port 1-8 on the OS DC – i.e. do not connect relays to COM, but always connect solenoid valves to COM. This bypasses the booster.
Solid state relays have no mechanics like traditional relays, so they are more reliable and durable.
Another interesting feature of the DC version is that the solenoid valves no longer ‘hum’, but only ‘click’ when they are switched on and off. And the boost time can be set in the options.
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!
You can order the ‘standard power supply unit’ with both the AC and DC OpenSprinkler. The AC is the 24VAC 1,5A, the DC is the 7.5VDC 2.93A plug-in power supply.
Yes, really: With the OpenSprinkler DC you can use 24VAC solenoid valves without any problems! Read the history of DC technology here.