12V and OpenSprinkler DC

[Admin]

Some customers have noticed that the OpenSprinkler runs when using a 12V power supply, e.g. a DIN rail power supply gets quite hot.

A voltage regulator is used internally, which reduces the voltage from 12V to 5V. This voltage regulator is rated up to 15V and can indeed get very hot. The connected solenoid valves do not load the voltage regulator because they are controlled via a different circuit.

However, things become problematic when additional consumers come into play and the outside temperature rises at the same time.

Consumers that can be connected directly are sensors, A2D converters and the network adapter. The network adapter in particular draws 150mA and is therefore one of the main consumers.

Due to the higher power consumption, the temperature also increases and this can cause the voltage converter to burn out. Likewise if the voltage is not 12V but 13-14V.

For this reason, in this case we recommend using an external voltage converter that can reduce the voltage to 7.5V.

For example, there is a “Step-Down Converter Adjustable 5-36V 5A Voltage Regulator Converter Module Kit LED” on eBay for 10EUR with which you can regulate the voltage precisely to 7.5V. This can then be attached to the housing with double-sided adhesive tape or Velcro.

The temperature can be checked as follows: During operation, check the contact opening of the OpenSprinkler on the left with a temperature measuring device. Alternatively, touch it briefly with your finger, don't worry, there is no great tension here. >40° is actually too much and you should use a voltage converter.

[nightingale]

Thanks for the info. One question: does this also apply to the OSPi?

[Admin]

No, the OSPi uses a 24VAC-DC converter. If the power consumption becomes too high, the Raspberry PI reboots.

The OSPi up to version 1.44 can output a maximum of 5V/0.5A = 2.5 watts of power,

The OSPi from 1.5 can deliver a maximum of 5V/2A = 10Watt power.

[Author]

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