Aratyhq Posted March 1, 2013 Report Share Posted March 1, 2013 Before using a relay, realize that: 1. Most power amps and processors require between 10 and 20 mA of current to power the turn-on circuit 2. A "bosch" type relay requires between 110 and 120 mA of current to power the coil 3. Most source units are capable of between 250 ma and 500 ma or current on their turn-on leads (this will be specified in the owners' manual) Finally, connecting a relay as shown to the turn-on output of a source unit could actually damage it. I would strongly recommend installing a diode across the coil of the relay (in reverse bias - stripe side to turn on lead and non-stripe side to ground). When power to the coil of a relay is turned OFF, the electromagnetic field within the coil collapses. This can in some cases result in a very large voltage spike traveling up the turn-on output of the source unit, which could damage it. The diode will shunt this spike to ground, thereby making the addition of the relay harmless. I hope you get to see this as I think I did this correctly, this is a diagram I made of how I wired my relay with the diode. Just like this ... ok, thank you Link to comment Share on other sites More sharing options...
AvionicsTek Posted April 24, 2014 Report Share Posted April 24, 2014 Before using a relay, realize that: 1. Most power amps and processors require between 10 and 20 mA of current to power the turn-on circuit 2. A "bosch" type relay requires between 110 and 120 mA of current to power the coil 3. Most source units are capable of between 250 ma and 500 ma or current on their turn-on leads (this will be specified in the owners' manual) Finally, connecting a relay as shown to the turn-on output of a source unit could actually damage it. I would strongly recommend installing a diode across the coil of the relay (in reverse bias - stripe side to turn on lead and non-stripe side to ground). When power to the coil of a relay is turned OFF, the electromagnetic field within the coil collapses. This can in some cases result in a very large voltage spike traveling up the turn-on output of the source unit, which could damage it. The diode will shunt this spike to ground, thereby making the addition of the relay harmless. ^ This. A relay is always a good idea for using your head unit's remote turn-on power to turn on multiple amps, because a relay coil's current-draw stays pretty consistent with a continuous duty cycle, and you can run a larger power wire through the switch poles of the the relay to your amp(s) remote inputs The relay switch poles then sustain the current draw from your amp's remote turn-on relays, instead of your head unit sustaining that draw. I have my remote wire run to a 12v 40a bosch relay to turn on my multiple amplifiers (including a kill switch for the sub amps remotes so my wife can turn them off when she's driving my baby). That first relay, in turn, supplies power to another relay with a ground running through it to bypass my parking brake ground-input on my dvd player. Just make sure, as snafu noted, to use a diode to shunt the coil to ground to protect your power from traveling the wrong way into your head unit. I also used a relay (connected to a DC-rated switch) to turn my backup camera into a rear view camera so it also works when ever I flip the switch as well as automatically when I'm in reverse. Then I have another relay (connected to another switch) to enable/disable my fuel injection relay, so I can change the tuning for my diesel fuel-injection without opening the hood and pulling the actual fuel injection relay. When it comes to safe and stable power/ground (both carry current) switching, relays are your friend. I should know...I've got an entire bank of relays for controlling things at my leisure. Link to comment Share on other sites More sharing options...
Fullcycle Posted June 23, 2015 Report Share Posted June 23, 2015 Do you guys use a Disconnect wire connector (bus bar) after coming out of relay? I was looking at hooking three amps plus the SMD-TM-1F with four fans. Link to comment Share on other sites More sharing options...
RobertSexton Posted April 19, 2016 Report Share Posted April 19, 2016 thanks for the info Link to comment Share on other sites More sharing options...
moh.vze.com Posted February 22, 2018 Report Share Posted February 22, 2018 I've been using the remote lead on my Kenwood X895 wired to my DC 5K amp and daisy chained that amp to my second amp (RF t800-4ad) but I'm thinking about adding a third amplifier (eD Nine.2 ) and was considering using a relay. How many people on here don't use a relay and just daisy chain 3 amplifiers together? I've never used a relay before but I was considering this eBay one: https://www.ebay.com/itm/220386357483 DC Audio - Singer Alternators - Knukonceptz - XS Power - Hybrid Audio - Rockford Fosgate - Second Skin Audio - SMD - Sundown Audio - Elemental Designs Link to comment Share on other sites More sharing options...
alex912005 Posted February 22, 2018 Report Share Posted February 22, 2018 47 minutes ago, moh.vze.com said: I've been using the remote lead on my Kenwood X895 wired to my DC 5K amp and daisy chained that amp to my second amp (RF t800-4ad) but I'm thinking about adding a third amplifier (eD Nine.2 ) and was considering using a relay. How many people on here don't use a relay and just daisy chain 3 amplifiers together? I've never used a relay before but I was considering this eBay one: https://www.ebay.com/itm/220386357483 I do, and it works. My Build Log Link to comment Share on other sites More sharing options...
SkarredSierra Posted February 22, 2018 Report Share Posted February 22, 2018 You could always get a lil mini bus bar too. 10 bucks on ebay. Less wire to run. Just connect it to an open accessory spot on your fuse panel. Make sure to fuse it also in case of an accident or short. Link to comment Share on other sites More sharing options...
Mr DeeBeez Posted February 22, 2018 Report Share Posted February 22, 2018 I daisy chained three amps on my last build, but will be using a relay this build for 6 amps. Fi Team 18's (4) Crossfire 16k Crossfire 400.4 & 800.4 Pioneer AVH-X491bhs 140ah cmax CES 320's (2) Link to comment Share on other sites More sharing options...
n8ball2013 Posted February 22, 2018 Report Share Posted February 22, 2018 It’ll work til you free the remote lead. THERE IS NO BUILD LOG! 1998 Chevy Silverado ext cab Alpine CDA-9887 4 Team Fi 15s 2 Ampere Audio TFE 8.0 2 Ampere Audio 150.4 3 Digital Designs CS6.5 component sets Dual Mechman 370XP Elite alternators inbound! 8 XS Power d3400 6 XS power d680 Second Skin Stinger Tsunami Wiring Sky High A Real Voltmeter not a piece of shit stinger. Link to comment Share on other sites More sharing options...
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