relay q?

[00CericaRuss]

how long can i keep a relay switched on for?
is it ok to have it kick on when the car turns on and leave it on till i turn the car off?
will it fry quickly?

[JL Tech]

That's no problem, cars have many relays that do just that. You don't want a relay energized when the ignition is off. The current draw can kill a battery if the car is not driven each day. When you think about it, a relay energized when the ignition is on isn't really on all that long each day. It should be no problem for a BOSCH or P&B relay. Some or the more dubious relays from Pep Boys fog light kits would be suspect.

[SQ GT-S]

Yeah, a relay in the on position draws a few hundred mill-amps or less. Leaving them on is no big deal. All auto parts stores carry the basic relays. Just ask for a basic 10-amp relay.

Curt

[00CericaRuss]

cool... i was just checkin....
i have a problem when my computer powers off in my car w/the amp still on, it makes my woofer give a big thunk so i need to power off my amp before the computer to aleviate it, so i'm just gonna run the remote turn on off a relay so that it shuts off right when the computer receives the signal to shut down

[PacificBlue]

Maybe one of these would help...

STINGER Pop Stoppers $16.99 ea:
http://autosoundgear.com/images/products/POP_STOPPERS.jpg

SPSON: delays the amplifier(s) turn-on lead 1 second to eliminate undesirable pops from the amplifier(s) when turning on an audio system.

SPSOFF: eliminates ignition turn off pop by allowing the amplifier to turn off 1 second before the radio.

Check 'em out here: http://autosoundgear.com/tek9.asp?pg=products&specific=joimcmk8

[00CericaRuss]

eh.. that wouldn't really help because the remote turn on is wired through my shutdown controller for the computer...
this is what happens:
car, computer, amp on
turn off car
shutdown controller sends signal to computer telling it to shutdown
computer and amp are still on (power is still on on them)
computer powers off after x amount of time, makes big pop in woofer
power still on
time goes by, power turns off

[PacificBlue]

Got it. Interesting problem, clean solution.

I tried searching the web for PC shutdown speaker "pop" probs and you'd think for such a common problem (esp. when connected to expensive PC amps & surround speaker systems) there's almost nothing available out there. Closest thing I found was way seriously serious where the guy built a multiple-relay microcontroller using a Basic Stamp module programmed to hack the ATX power supply's control lines and sequentially power his PC supply, super-cooler supply, and a few other external goodies any way he wanted. Pretty soon we'll be adding "NASA" to the graphics on our Celi's.

[SQ GT-S]

Or just run a relay off the output off the amp before the speaker. Trigger the relay to turn on after all the gear is on, then turn the relay off before everything else.

Curt