ignition sense emulator

Hi All

Given the increasing difficulty picking up an ignition on / engine run feed from modern cars, can anyone suggest a product or circuit which would emulate such a signal?

Given that a modern alternator delivers about 13.8V as a minimum, I'm thinking about a bit of circuitry that switches at 13.5V, as even a brand new battery would not be able to sustain that quiescent voltage without input from a charging source

Your thoughts?

What problem. There's ALWAYS a circuit somewhere. What are you trying to do?

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

For sure there is!

But if I have Engineers on a three wire tracker install, why waste time looking for a true engine run or ignition on if there is a simpler solution?

I can't think of one single car anywhere that doesn't have an easily accessable ignition circuit. Designing a simulated ignition would be much more work...

-------------
Mike M2
Tech Manager
CS Dealer Services

i must have read this a dozen times, but i still dont know what hes trying to achieve...

making an ignition circuit ? i am going by what mike mentioned.

-------------
Ted
2nd Year Tier 1 Medical School
Still installing as a hobby...pays for groceries
Compustar Expert

It reminds me of those that want a voltage sensing "smart" battery isolator with all the problems of what voltage to set it at (eg, 12.5V to 13.5V), the delays required to prevent hunting and surged responses etc.

Why?
Because it is "too difficult" (sic) to find the alternator's charge lamp circuit - even when it is the only wire coming off the alternator (power excluded obviously).

Caveat: At least that's what some reply, though it seems those replies are on behalf of the OP by someone that sells isolators (who would have thought!) or even dc-dc converters!   

The bottom line seems to be either find a particular wire and add a relay of your choosing (15A or 500A), or spend $25 to $125 on a "smart"(sic) isolator (and then add your own relay if extra capacity is required), or maybe even $500 for a 40A dc-dc battery charger dc-dc converter.


Of course I'm talking about responding to a charging system.... (which is what the OP seems to want).
But how hard is it to find a wire that conducts with a particular device on - whether ignition or alternator, whether sensing its voltage or current?

I have installed up to 25 trackers in a day, the VTU ignition wire is only a sensor to "kick it into life" when the vehicle starts moving at over 11 m.p.h.. You can use ANY ignition or acc feed. The ignition wire's draw current is so low as to be unmeasurable with a DMM.
Heck the main draw is 3-5milliamps, join them together if you have to.
My main problems are "stealthing" the units and devising ways to test whether the fiddlers have got at the units.
Think laterally, Peugeot 407 estate recently, nasty car to take down the dashboard, AND a metal film windscreen, go to the left rear, trunk (hatch) light and a power outlet. The power outlet becomes your 12V= constant and ground, the trunk light shuts down on a timer (sleep circuit) so that becomes your ignition. Ditto Astras behind the glovebox, it's illumination 12V+ shuts down.
Maybe Mr Kevinlynchehaun you should PM me for advice and work if your installers are having problems.

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