I'm installing a security system w/ remote start and keyless in my Jeep. What size relays would I need to use for the auxillary's to turn my heated mirrors on, dome light, etc? The guy at the car stereo shop said you can't use a relay too big, and that sounds right since relays just move current one way or the other, but just checking. I know for the starter kill, it came w/ a 30 amp relay.
What size relay?
- Thread starter TheUser
- Start date
Look at the fuses that feed the items you want to control. You don't need a relay with more current capacity than the fuse and you don't want one smaller.
A second clue is the wire size: look at the size wire recommended to feed the accessories. Use a relay equal in current carrying capacity to the wire size.
Quick & dirty wire size table:
18 gauge = 5 amps
16 gauge = 10 amps
14 gauge = 15 amps
12 gauge = 20 amps
10 gauge = 30 amps
8 gauge = 60 amps
A second clue is the wire size: look at the size wire recommended to feed the accessories. Use a relay equal in current carrying capacity to the wire size.
Quick & dirty wire size table:
18 gauge = 5 amps
16 gauge = 10 amps
14 gauge = 15 amps
12 gauge = 20 amps
10 gauge = 30 amps
8 gauge = 60 amps
JR is spot on. great tip on checking the OEM circuit fuse rating and AWG size.
ill add that bosch 30 amp SPDT relays are very common (what i use). you can get sockets to go with them (like your starter kill relay has - but that socket is different so dont use it for other things!).
good luck and have fun with the install.
oh yeah, if you are gonna have a good number of features on there, i might read up on blocking diodes (if you are not familiar with them) as they may be beneficial in your install. (your starter kill relay socket likely has one, for example).
good luck.
ill add that bosch 30 amp SPDT relays are very common (what i use). you can get sockets to go with them (like your starter kill relay has - but that socket is different so dont use it for other things!).
good luck and have fun with the install.
oh yeah, if you are gonna have a good number of features on there, i might read up on blocking diodes (if you are not familiar with them) as they may be beneficial in your install. (your starter kill relay socket likely has one, for example).
good luck.
Thanks guys.HISSIN50 said:
HISSIN: What sockets do you speak of? I've already gotten about half of it installed, just waiting to get the relays and finish it off...hopefully. The Jeep is torn apart ha ha. I've read a little about blocking diodes; hopefully, I can get away without using them because I want this to be as simple as I can get it. However, I do need to get some diodes and play around with them sometime and learn about that stuff.
you probably knew this, but a socket is the plastic connector that houses the terminals from the wiring to the relay. like your starter-kill feature probably came with a relay and a socket - black connector with 4 wires on it (and a diode running across two of the wires in the socket).TheUser said:
here is a link to one:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=330-075
they also sell double sockets (or piggybacked sockets) as i recall. those can be cool for alarm installs (but certainly not necessary).
are you wiring in a motion sensor or anything else that uses the shock sensor? if so, i would break out blocking diodes (Radio Shack has them).
good luck - sounds like you are most of the way done.
lol HISSIN, you give me too much credit, thanks. I really am kinda new to electronics as far as all these diodes and stuff, so I didn't know what a socket was, but now I do...awesome...makes sense Yeah, my alarm did come w/ one of those now that I think of it. I've sourced some relays at a stereo shop, wonder if they have the sockets too? Guess i'll ask 'em when I go lol. Would be a lot easier than soldering wires in there ha ha...Thanks man, you're the best!
or do what i do (not that it helps you now). order a few times a year from PE. ill get ~20 relays, some sockets, electrical terminals, etc from them. it way more than pays for shipping if you are stocking up. get a door lock actuator or 2 if you envision doing JR's retrofit (highly recommended by me when the time comes).
stereo shop might have sockets - i think most do. around here, stereo shops charge an arm and a leg for that stuff (relays are around 4 times the cost of getting them online).
ill add something i do. once in a while a relay will fail. when i install them, i write on the relay with a silver sharpie what the relay is for (i sometimes do it in a foreign language if the relay is not buried), not that it really matters. some installs of mine will use double digit relays so it helps to have them labeled.
im full of other useless things i do, but i will stop.
good luck with the rest of the install. it is pretty satisfying to put one in yourself - you enjoy it every day and it is tangible.
stereo shop might have sockets - i think most do. around here, stereo shops charge an arm and a leg for that stuff (relays are around 4 times the cost of getting them online).
ill add something i do. once in a while a relay will fail. when i install them, i write on the relay with a silver sharpie what the relay is for (i sometimes do it in a foreign language if the relay is not buried), not that it really matters. some installs of mine will use double digit relays so it helps to have them labeled.
im full of other useless things i do, but i will stop.
good luck with the rest of the install. it is pretty satisfying to put one in yourself - you enjoy it every day and it is tangible.
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