low voltage trigger
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=101665
Printed Date: April 28, 2024 at 9:24 PM
Topic: low voltage trigger
Posted By: wireman121
Subject: low voltage trigger
Date Posted: January 28, 2008 at 5:01 PM
Here is my delema: I am looking to design a low voltage trigger. The purpose of this would be when the vehicle's voltage reaches a preset value (lets say 9.0V) it will close a switch, and send 12V+ to a trigger wire. The trigger wire will be attach to the 12V+ input trigger of a remote start module. The purpose of this would be in the event that a light is left on, or something else draining the battery, before thhe battery completely dies, this module will trigger the remote start to engage, and of course charge the battery back up. I found 1 voltage sensor here https://www.tessco.com/products/displayProductInfo.do?sku=466627&eventPage=1 but it isnt exactly what I was looking for, and I'd rather make my own, but i obviously need a little help. Any help is appreciated
Replies:
Posted By: techman93
Date Posted: January 28, 2008 at 10:32 PM
I am wondering how you would start vehicle on less then 12 volts. Normally a vehicle starts very hard if voltage is under normal. I think it would kill battery all together due to trying to crank requires more voltage then 9 volts and so if it did start it would run for preset time and die again if unattended. Say you go on vacation and you have a voltage drain in your car. It would constantly turn car on every time voltage reached a set point and charge back up over and over again, I think that will cause fatigue on battery and reduce life of cells and what if your car expends all the gas in the fuel tank? What would you do to prevent that?
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The wire I'm test'n isn't doin' what it's supposed to be doin'... I am so glad I printed that tech sheet, with the wrong info.
Do it right the first time... or I might have to fix it for ya
Posted By: brcidd
Date Posted: January 29, 2008 at 8:22 AM
not to mention- that this car may sometime be in a garage- in a home- with the door down--- The better solution is the old "battery buddy" - a device that attaches to your battery that when voltage drops below 12 volts are so- that the box- switches off (unhooks) your battery- then when you try to start it up- it automatically re-connects your battery- when you turn the key- very simple install- all automatic-- had one on the wife's van when my daughter used to leave map lights on- saved her numerous times-- of course any newer vehicle now have this battery saver cicuitry built into them...... ------------- Brcidd - Engineer That Does Remote Starter Installs on the side.
Posted By: ralphtonka
Date Posted: January 29, 2008 at 9:19 PM
the rs would shut down if voltage fell to 10.5 v while cranking. get the battery buddy!
Posted By: Chris Luongo
Date Posted: February 03, 2008 at 12:40 PM
wireman121, still here?
https://www.autospeed.com/shop/category_579/browse.html
About halfway down the page, check out "universal voltage switch."
Posted By: KPierson
Date Posted: February 03, 2008 at 6:33 PM
You would be better off designing something that would disconnect the parasetic load rather then trying to start the vehicle. OEM setups cut all power to interior accessories ~15 mintues after the ignition has been shut off, this prevents interior accessories from killing the battery. It wouldn't take much more to add the headlights to the scheme.
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Kevin Pierson
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