Battery switch activation via security system?
 

Need some advice/confirmation on what I want to do with my Cobra Electrical system. Pls refer to the attached electrical diagram (in particular, the lower right hand corner).

Background: I will not have a keyed start option. I’ll have a on/off switch for ACC and Ignition On and a start button. For security, I’ll have a remote battery switch that’s activated electronically when you supply a ground to it (i.e., no manual key to turn on). I will also install a Viper 5901 security system.

Plan: I want to add a simple standard relay switch to the remote battery switch to supply the ground to it to supply power to the car. I want to activate the relay with a negative input from the Viper security system. When the Viper is disarmed, it can provide a Aux/trunk 200mA negative output. I’d connect this output to the relay. This in turn would provide a higher amp negative output to the battery switch. The battery switch is the Painless # 30204 (http://www.summitracing.com/parts/PRF-30204/ ). It came with a toggle switch to supply the ground… but obviously, this is not a secure option… therefore why I added the relay and connection to my security system. Not knowing the amp draw on the battery switch negative/ground activation, I’m playing it safe by adding the relay for the ground.

So, my question to those that understand electronics…. Do you believe the 200mA negative output from the security system will work OK to supply the ground to the reply switch to activate it and therefore offer a good ground to the battery switch to cause it to active?

If you need any further clarification…. Pls ask.

Thanks to all in advance…. Mark

Mark, you're planning on buying a simple automotive relay and using that relay to provide the ground to that nice Painless solenoid, correct? You can find relays that will draw under 200mA. If you know that your automotive voltage can be as high as, say, 14.8 volts, and you've only got 200mA to play with, then the resistance across the coil of the relay must be 74 ohms or greater. If you click on this page: http://www.allelectronics.com/make-a...-Relays/1.html you'll see two automotive relays. One with a resistance above your cut-off, and one below. So, in theory, the 88 ohm relay would work. There's not a whole lot of margin for error though, and the intial draw from the coil will spike above your 200mA number -- who knows if that will take its toll on the Viper. Plus, if that little relay "blinks" because of either a current overload, or just a blip from the Viper, then you're disonnecting your batter while the car is running. Not good. Personally, I'd hide a switch somewhere that only you knew about instead of using the relay being fed from the Viper.

Correct. The battery sw itself has a built in relay and not knowing it's requirements, that's why I was inserting a 30 amp relay between the Battery sw and the security system. So my inserted relay would give the ground to the battery sw relay.

Thanks for your help. I'll check out your link. Mark

Well, here's the latest plan...
1. Use my Painless Battery Sw via a relay as planned... but with a 5 pin relay (one that has post 87 and 87a outputs) Where 87a is the default relay switch connection when NOT activated. 87A will provide the ground to the Painless Battery sw. The Viper Security has a -500mA output when ARMED.... and will drive this relay to the Batt Sw. and therefore disconnect ground by switching from 87A to 87 (87 will not be connected to anything). This way, if the Viper dies, I have ground to the Batt Sw by default, therefore, pwr to the car. I’ll add the toggle switch that came with the Batt Sw between the relay and the batt sw as designed. Again, another way I can kill the Batt sw.

2. Viper disconnect of Starter
3. Viper disconnect of MSD Ignition box.

I'll still install the back door, carry extra relays and several male-to-male 1/4" spade couplers to bypass the relays if all else fails.

The Viper 5901 also has a long range feature in that the LCD remote FOB has up to a mile range and will monitor the security system and let you know of any activity. I just received the VSM100 Viper Smart Start option that adds cell network connection so I can access/control via my iPhone. This way, I can monitor the car anywhere I have cell connection and not need the FOB (the iPhone will lock/unlock, receive alerts, etc). Obviously I won't use the remote start feature... not much use in a open Cobra .:3DSMILE:

And, yes, I know this is all an overkill, but I can't help myself.... I love "gizmos and gadets". Over engineering isn't bad, is it? :confused:
Mark

Better...
 

I think that will certainly stop impromptu, drive-away, amateur thefts. But, if I was going to steal your car, and I had no idea what sort of security/protection you had, I would just pop the hood, cut the big battery cable, and tow it away on my flatbed with a car cover over it. Thoughts:

1) Does your security system continue to work/notify you if the 12v battery is cut?

2) A very simple, fast & friendly theft deterrent is a quick-release steering hub. A thief sees that the car has no steering wheel and quickly realizes that the only way he can steal it is with a tow. You can either lock the steering wheel in the trunk, or take it in to the restaurant with you (yes, Chas., that was for you). Removing the steering wheel also discourages people from sitting behind the wheel and playing "vrrooomm, vrrooomm."

3) Consider some obvious physical security to thwart pushing/towing away. What I use from time to time is a very heavy cable lock looped through the wheels. I have even seen cars that ran an extra cable around a telephone pole, or the like, when parked, maybe at a hotel, away from home. It's very simple to carry in the trunk. That will stop most tow away/push away thefts. You need a pretty serious set of cutters to get through this type of cable. Here's a pic:

http://www.clubcobra.com/photopost/d...um/lock001.JPG

1. Yes, I have several battery backups... one for the actual system and a backup Siren with backup battery built in.
2. Got that one covered... i.e, I will have a quick-release steering hub
3. this is a good idea. I have for my car hauler trailer a "hook" device to the wheel.... see link. maybe one for the car? http://www.etrailer.com/Locks/Winner...l/WI491KA.html or this one http://www.etrailer.com/Locks/Valley/V75712.html

Thanks Mark

Ask them to pave their parking lot-you have stone chips!:eek:

No steering wheel, obvious lock on the wheel that keeps me from towing/pushing it away, and a backed-up electronic alarm protection. If I were a thief I think I'd move on to the Toyota down the street.;)

And Chas., those were dirt marks, not stone chips.:p