multiple relay setup

Hey guys.  Thinking about working on a basic remote start relay system.  I understand that to buy one is easier and safer but I am set on building my own.  It will be a good project to work on.  I will be using the diagram located in the relay faq.  I have two questions.  Thanks.

1.)  This system requires multiple relays and I was curious to know where is a good place to buy bulk relays?

2.)  Also packaging is an issue.  Would it be a good idea to use mini relays?  Is there a fuse box/relay holder that anyone would recommend for multiple relays?

There are many places online to buy bulk automotive relays. I would do some internet searching and you should be OK. I would highly recommend buying relay harnesses with the relay. I would also highly recommend finding a harness that is "stackable" to keep things neat and orderly.

Without listing your vehicle it is hard to say if you can get away with Mini Relays. Typically the smaller something is the less current it can safely carry. Most production remote start systems are setup to safely operate 30A circuits (relays and wiring). You will need to determine how much current each circuit in your vehicle will need and size the relay (and harnesses) accordingly.

As you already know (from your post) it is a terrible, terrible, terrible idea to do what you are trying to do. Any money you save will be negated by lack of features, lack of functionality, and most likely hours wasted messing around with the relays. There will be basically no one available to help you troubleshoot your "creation" so if you can't get it working you will be on your own.

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Kevin Pierson

Right on.  Thanks for the reply.  My vehicle is a frankenstein already so its hard to give any helpful information about it.  I will not need anything higher than 20amps.  I will do some research on stackable relays.  That sounds very promising.  Are there any brands that are better than any others? 

I don't use relays with the pin-outs shown in this site (ie, the DIN numbering and Bosch/Hella type relays. I use Jap JIDECO and similar due to the superior weather resistance, specific pint-outs (cant interchange DPST with SPDT), and 3-way mounting options.
I'll change their bases in relay-fuse boxes to suit the application.   

However I will not use the complex multi-relay circuits on this site unless there is a valid reason.
When a few relays can be replaced with simple components (eg, diodes or transistors), it is generally cheaper and simpler, and can be more reliable.

But as DY said, suitability depends on current rating.
Whilst the small "logic" part of the relay array can be almost anything (even small chip-type DIL relays, provided any RC timings are adjusted), the output relay has to handle the required current.


BTW - this site uses "physical" diagrams to make it easy for people to assemble its circuits.
I use line-type or circuit diagrams that show the logic and switching connections. The user can then apply that to whatever relays they choose. (Maybe with the12volt or me or others supplying the "physical" diagram to suit, though that's where I would rather "teach" users how to read and convert diagrams; it should not be that difficult, and it opens a new world of independence and possibilities.)

In the real world I'm 100% with K.P. here, also Oldie's comments, in the real world, using a "lash-up" the only things you will achieve will be loads of stress, marked hair loss and empty pockets repairing the damage. A decent "stand a lone" R.F. Tx/Rx unit will cost more than an RS purchased unit.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Factor in your labour spent on wiring up the relays plus the cost of the relays plus the remote receiver and transmitter, it's cheaper to buy a ready made and believe you me you will still learn!

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.