So I’m in the beginning stages of building a powered controller for heating blankets for nitrous oxide bottles. It’s a simple design that uses a drill battery 18v to be exact along with two powered switches. The circuit runs through a 25amp circuit breaker which feeds the switch and 24v relay. Then out to the heater. From time to time I get chatter in the relay. What could be the cause and what could be a simple fix? I’m using 30 as the main power, 86 pin as switched 85 as ground and 87 as feed. I’ve read about the use of a capacitor but I’m getting mixed directions on proper connections of the capacitor and which capacitor to use. Forgive me as I’m a hobbyist that isn’t very versed in this world but has excellent understanding of how these simple devices should work. I’ve been told by a few others this is normal but I don’t think so. Thanks in advance.

 

Welcome to AAC!

Likely causes are coil voltage too low or switched current too low.

How much current are you switching?

 

A Drill-Battery is not going to last very long running a Heating-Element of any substantial Power-rating.

What You may be experiencing is the "Voltage-Sag" of the Battery making the
Battery-Voltage too low to operate the Relay,
which is already trying to operate on an inadequate amount of Voltage,
and the Voltage drops even further because of the Heater-Load.
Then when the Heater is temporarily disconnected by inadequate Voltage at the Relay-Coil,
the Battery-Voltage then rises-up again enough to re-energize the Relay.

Lather-Rinse-Repeat,
You have now created a "Buzzer" from a standard Relay.
.
.
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