Hi all,
I had a fire in my car due to lipo battery that overcharged and caught fire.
I fly RC and charge the batterys in the trunk of my car on the way to the field. Be careful and always store and charge Lipos in a fire proof box.
I'm now using a metal battery box that is vented to a (battery operated) smoke detector.
This should work well if I am driving the car or near by. But what I really want is a way to switch a loud car horn if I am in the house or at the far side of the field.
OK so I am a bit of a nubee with correctly biasing a transistor to do the job.
I would like to use a common automotive relay.
Q1 Do I even need a transistor to drive the coil of a 12 volt common relay?
The smoke detector is a common 9 volt battery type.
I dont know what the draw is of a 12 volt relay coil , but I would hope its under 300 mA.
Q2 Can I take the 2 wires from the smoke detectors alarm/speaker.
and use a transistor to drive a relay?
Hope someone can chime in here with the correct parts needed.
Thanks very much.
Attached is a common wire diagram of a smoke detector.
I had a fire in my car due to lipo battery that overcharged and caught fire.
I fly RC and charge the batterys in the trunk of my car on the way to the field. Be careful and always store and charge Lipos in a fire proof box.
I'm now using a metal battery box that is vented to a (battery operated) smoke detector.
This should work well if I am driving the car or near by. But what I really want is a way to switch a loud car horn if I am in the house or at the far side of the field.
OK so I am a bit of a nubee with correctly biasing a transistor to do the job.
I would like to use a common automotive relay.
Q1 Do I even need a transistor to drive the coil of a 12 volt common relay?
The smoke detector is a common 9 volt battery type.
I dont know what the draw is of a 12 volt relay coil , but I would hope its under 300 mA.
Q2 Can I take the 2 wires from the smoke detectors alarm/speaker.
and use a transistor to drive a relay?
Hope someone can chime in here with the correct parts needed.
Thanks very much.
Attached is a common wire diagram of a smoke detector.
Attachments
-
7.2 KB Views: 38
-
3.1 KB Views: 22