One thing I don't like about our TL (and other cars) is that ACC power is interrupted when engine is being strated. AFAIK there 2 historical reasons for the ignition key working this way.
1. To provide all available power to the starter.
This may be important only when battery is in pretty bad shape, but even then, one could manually turn off all ACC power consumers.
2. To protect electronics from power spikes caused by the starter
I think that it's been irrelevant for a long time. Modern cars have all necessary surge protection in all circuits. THe most sensetive of them all- the engine computer stays on during starting, and most others- radio, navi, have another uninterrupted power lead.
So, I am thinking about installing a timer circuit, which will keep ACC power on for let's say 30 seconds. It will provide two benefits:
1 You can program navi, than start the car and not have to wait for reboot, press OK button and so on. Radio will not be intrrupted by starting.
2 When you are ready to exit the car, radio will continue playing for another 30 seconds after you remove the key, end you can enjoy the music until after you slammed the door. If delay is set to 10 minutes, you can actually leave the car return and find navi still working.

What do you think guys?

 

I think that's a pretty cool idea. How would you do it? An automotive relay and a TR7?

 

It doesnt really bother me, since you can just push OK twice when the navi comes on to get the addy you had in.

 

Sounds like a cool mod, just not really necessary for me in my opinion. I think I seen that on Chevys befo, the radio stays on 'til you open the door then it shuts off!

 

I like the idea. Its like a backup UPS for a computer system. I wonder if they make mini UPS.

I find myself shutting off the car and watching a short video in my car while waiting for someone. When the person arrives, I need to shut off my media player before starting up the car again. With this mod, I could just start up the car and not worry about corrupting my hard drive media player.

 

More than once I've been in situations, when I programmed the navi, started engine and drove to an intersection before navi completed the boot process. Then we have those embarassing situations with stalled engine
I wanted to install this mod using as few components as possible, and I think that the best device would be a time delay relay. I found a company- www.macromatic.com which makes such relays. I identifeid the following part numbers: SS-8566 Code 07 08 10, TR-61626, TD-71626. Those are "Off delay" relays, they will turn off after programmable delay.
Zax what is TR7? I googled, but found only links to the car

Anyone can think of any negative consequences from this mod?

 

I would think if your plan is to be able to start the car while several accessories are operating like the Navi or DVD etc., you would not want the voltage drop associated with cranking the engine. Circuits will slowly degrade if subjected to under voltage more so than over-voltage in near all cases.. With a timer mod you would probably want a voltage regulator to ensure a constant 12v or more..


What would you think of installing a small say 7-10 amp "AUX" 12v battery with an isolator circuit?? Not sure of the number of existing Navi etc. power leads you would have to tie into, maybe just a simple isolated "one way" fuse box input...
Bottom line, in the event you want to have things remain on just flip a switch and isolate the required accessories to the AUX battery etc.. The aux battery could easily be charged though not drained by the car via a battery isolator etc..

I actually did this with a previous street rod though it was mainly for the stereo and aux cooling fans etc.. That way I could run them all I wanted yet not worry about killing the "start" battery.. Obviously didn't have to deal with tying into the factor accessories like navi though...


Just thinking out loud here..

 

The TR7 is an all-purpose timer module from PAC Electronics. It's AWESOME. I used it for my auto-rollup/down windows but it can basically be used for anything.

It's on this page: http://www.pac-audio.com/products/pr...gger%20Modules

Check out the instructions for what it can do. Basically you can use it to drive a high-current automotive relay which could latch the ACC line...

Good luck!