Large relays can have excessive pull in currents as the result of the large air gap of the armature. Once that gap closes, the current and the heat generated can be greatly reduced using common buck converters. This modification only adds a 1,000uF capacitor to the sense line to common to create a time delay before the buck converter drops the voltage. This time delay only needs to be about 30ms, the time it takes fr the armature to close and settle. This capacitor is connected to the pot pin which has the lowest resistance to common usually and the lowest voltage. The response is still fast enough tant the pull in and drop out voltage of the relay can be easily checked. Set voltage to just below pull in voltage. This would also work with a boost converter if the system was 12V and the relay was 24V. Some buck converters also have a shutdown pin. This may be lifted from the board and that input will turn the module into a relay driver.
Large relays can have excessive pull in currents as the result of the large air gap of the armature. Once that gap closes, the current and the heat generated can be greatly reduced using common buck converters. This modification only adds a 1,000uF capacitor to the sense line to common to create a time delay before the buck converter drops the voltage. This time delay only needs to be about 30ms, the time it takes fr the armature to close and settle. This capacitor is connected to the pot pin which has the lowest resistance to common usually and the lowest voltage. The response is still fast enough tant the pull in and drop out voltage of the relay can be easily checked. Set voltage to just below pull in voltage. This would also work with a boost converter if the system was 12V and the relay was 24V.
Some buck converters also have a shutdown pin. This may be lifted from the board and that input will turn the module into a relay driver.