Remote wire for multiple amps & processors

[SPL_Man 20]

guys i was wondering about a system that has say 10 amps & a couple of processors if the remote wire voltage from a typical deck will be sufficient or safe to turn on all of these or will a relay be needed to help boost the turn out voltage ?

what is usually the voltage out from a deck ?

what voltage is required for amps or processors to turn on ?

[ncacoates 104]

I personally would use a relay with a direct connection to the main battery or bank. Use the deck to actuate the relay.

[95Honda 486]

You should do your homework first.

You need to decide on your relay, most will choose a 30 amp Bosch. If this is the case you need to consider that the coil resistance of the relay may be low low enough that it pulls more current from your deck's power turn on lead than say 4 or 5 amps and processors combined... Figure between 50-75 ohms on the coil, so you need to do the math to decided if it is a good idea.

Many times people install one of these relays and actually pull more current from the deck than they would without it becuase they never actually thought about what they were doing... They also wasted money and made things overly complex...

If you actually have more current draw from all you devices than the deck can supply (unlikely unless you have a ton of shit) and you need a relay, you need to factor the coil primary resistance in when figuring out if your deck will be OK driving. Some decks will not be happy operating a standard 30 amp Bosch...

[dbsupra 69]

I understand what you are talking about with coil resistance but you aren't driving anything. You are just using the remote turn on as a trigger to energize a relay. We are talking mA here.

But I agree unless you are trying to turn on so much equipment it wont operate you may consider using a relay. Most of the head units I repaired back in the day had a 500 mA rating for the remote turn on. Things may have changed since then.

[95Honda 486]

That is the issue, some relays out there how a low enough coil resistance that they will pull close to your 500ma.... I have measured some in the 20-30 ohm range, this can be far worse than the remote trigger circuit of any amp...

[Sencheezy 689]

Use a relay.

[SPL_Man 20]

well thanks for the replies so far but unless i missed it nobody answered questions 2 & 3 ?

actually i am working on a "medium size" system that has 7 (maybe 8 amps later on) & also 2 processors in it too , dont want to give details on the system as yet until its done

so far i have used just the deck's remote wire (pioneer 1400dvd) & ran the system for about 2hrs of testing with no signs of problems as yet but i'm wondering if i'm "straining" the deck's rem wire power or if i shouldnt be using just that alone

i dont want to use 12v from the batt with a switch to turn the amps on since yrs ago when i tried that i notice u get unwanted noise coming through the speakers

[95Honda 486]

Your are probably OK. That is a lot of amplifiers and processors...

The voltage out of the deck will be the same as the nominal input voltage (your battery voltage)

The voltage required to turn on most amps will be from around 7-9V on up, depending on circuit. None need exactly 12V or more...

If you are worried about the current draw and want to use a relay, try and choose one with a primary coil resistance greater than 75 ohms.

You will wire the feed from any 12V source as the turn on circuit is isolated form the amplifier. If you ever had noise from running a switch like you described either the instal or equipment was faulty, that is the only way this will happen.

Good luck and I hope this helps!