Print Page | Close Window

Is a Starter Kill relay a bad idea?

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=141461
Printed Date: December 01, 2021 at 2:32 AM


Topic: Is a Starter Kill relay a bad idea?

Posted By: prince504
Subject: Is a Starter Kill relay a bad idea?
Date Posted: July 01, 2016 at 12:20 AM

To all the installers out there, how often do you install a Starter Kill relay in your clients vehicles?

A customer wants a 2-Way Alarm system and am undecided on whether to offer the relay (in addition to the typical shock sensor & horn sounds) due to fear of it failing and causing the vehicle not to start.

If the relay fails, can the car still be started? What are your experiences with them?

Thnx




Replies:

Posted By: kreg357
Date Posted: July 01, 2016 at 2:04 PM
Actual relay failures are quite rare. Starter Kill circuits allow for normal keys starts using the NC legs of the relay
( 30 to 87a ), another very low failure point. The main issue is wire connection reliability and the 5 wire relay harness
/ socket quality. If you want the best possible reliabilty, you should omit the 5 wire relay harness and solder all
connections.

I have had bad 5 wire relay harnesses, typically at the crimped lug connectors. Done correctly, I have no problems with
directly soldering the 12 gauge wires directly to the relays' spade terminals.

-------------
Soldering is fun!




Posted By: prince504
Date Posted: July 01, 2016 at 3:25 PM
kreg357 wrote:

Actual relay failures are quite rare. Starter Kill circuits allow for normal keys starts using the NC legs of the relay
( 30 to 87a ), another very low failure point. The main issue is wire connection reliability and the 5 wire relay harness
/ socket quality. If you want the best possible reliabilty, you should omit the 5 wire relay harness and solder all
connections.

I have had bad 5 wire relay harnesses, typically at the crimped lug connectors. Done correctly, I have no problems with
directly soldering the 12 gauge wires directly to the relays' spade terminals.


Thnx for the responce!

I don't know why but it never occurred to be to just solder and heat shrink directly unto the relay -- yes it takes a little longer but done right it should allow for a much better connection long term.

I have often found the wires that come in the harnesses to be really thin (especially at the 85 & 85 pins). Hence forth, I will try to purchase the the relay piece by itself & solder my own wires.

What are your thoughts on using spade connectors instead?




Posted By: kreg357
Date Posted: July 01, 2016 at 4:05 PM
Relay Pins 85 and 86 are a thinner gauge because the relays coil doesn't require much current. I will use up to 20 gauge
wire on them.

As for spade connectors, you can use them if you have a high quality crimping tool. A good compound crimping tool can easily
go for over 100 dollars. The ones found at WalMart cost $15. There is a big difference in the crimp results between the
two.

I usually advise my customer about the pluses and minuses of a Starter Kill / Anti-Grind circuit to ensure they are aware
that the vehicles Starter wire will be cut. Never had a come-back but I do spend extra time to ensure every connection is
perfect.

-------------
Soldering is fun!




Posted By: howie ll
Date Posted: July 01, 2016 at 4:08 PM
I buy the bases and the terminals separately use a non insulted crimp too AND drop solder them.
Again, never had a failure.


-------------
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.




Posted By: prince504
Date Posted: July 01, 2016 at 5:37 PM
kreg357 wrote:

Relay Pins 85 and 86 are a thinner gauge because the relays coil doesn't require much current. I will use up to 20 gauge
wire on them.

As for spade connectors, you can use them if you have a high quality crimping tool. A good compound crimping tool can easily
go for over 100 dollars. The ones found at WalMart cost $15. There is a big difference in the crimp results between the
two.

I usually advise my customer about the pluses and minuses of a Starter Kill / Anti-Grind circuit to ensure they are aware
that the vehicles Starter wire will be cut. Never had a come-back but I do spend extra time to ensure every connection is
perfect.


I figured that is why they were so thin since the relays I believe need 200-250mA as a trigger input. You say you use at most 20AWG on them, but what if your trigger is an IGN or ACC wire? Wont the current be too much for such a thin wire?




Posted By: prince504
Date Posted: July 01, 2016 at 5:40 PM
howie ll wrote:

I buy the bases and the terminals separately use a non insulted crimp too AND drop solder them.
Again, never had a failure.



Where do you get non-insulated crimps & how do you "drop solder"




Posted By: kreg357
Date Posted: July 01, 2016 at 6:49 PM
Wont the current be too much for such a thin wire?

While it is always best to fuse any install added device *, as you mentioned a relays' coil only draws less than 1/4 amp. Even if you ran a 4 gauge wire directly to the battery, the relay will still only draw < 1/4 amp. It's not the source and the available current but the device that demands / draws the current.

* Interesting point : The ADS AL-CA bypass module install on a newer F150 for 3 x Lock stand-alone operation is so simple ( like 30 minutes, including module flash, start to finish ) that I find time to add a fuse to the module which isn't shown in the iDatalink install guide. posted_image

posted_image

-------------
Soldering is fun!




Posted By: prince504
Date Posted: July 01, 2016 at 7:18 PM
kreg357 wrote:

Wont the current be too much for such a thin wire?

While it is always best to fuse any install added device *, as you mentioned a relays' coil only draws less than 1/4 amp. Even if you ran a 4 gauge wire directly to the battery, the relay will still only draw < 1/4 amp. It's not the source and the available current but the device that demands / draws the current.

* Interesting point : The ADS AL-CA bypass module install on a newer F150 for 3 x Lock stand-alone operation is so simple ( like 30 minutes, including module flash, start to finish ) that I find time to add a fuse to the module which isn't shown in the iDatalink install guide. posted_image


Wow, that does make sense. Even if there is 5amps going the ignition wire, the relay would only pull about 250mA of that for the trigger and nth else... Great info.

So hypothetically, if I wanted to trigger a device using either a (+) brake or IGN input & a single relay, I could wire both to pin 86 of a relay (85 to ground) and use two 1A diode to isolate both circuits?

I really appreciate your insight...





Posted By: howie ll
Date Posted: July 02, 2016 at 1:51 AM
Drop solder = crimp then solder.
As for where to get, anywhere! R/Shack, Farnell, Scosche, Metra etc. etc.

-------------
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.




Posted By: prince504
Date Posted: July 02, 2016 at 2:19 AM
howie ll wrote:

Drop solder = crimp then solder.
As for where to get, anywhere! R/Shack, Farnell, Scosche, Metra etc. etc.


I see... Thnx!





Print Page | Close Window