Ok Here are a few of the reasons.

Dead battery and still be able to pop trunk with keypad or interior button
Car Alarm could be tied to same circuit so that even if the car battery is unhooked the alarm could scream away.
ECM would not have to relearn.
Stereo Settings will be saved. (with my newer deck, it takes a good 30-45min to reset all the settings, theres a lot of stuff, 7band equalizer, with 8 savable programs, thats 56 tweaks to make just for the EQ let alone, infrared, local, beep, too much to list)

Could be handy for many things.

Ok here is what I am thinking.

You are going to need a battery Strong enough for trunk, alarm, stereo and ECM. I have not got a clue how much power that would need. But I am thinking something the size of an old Video Camera or Brick Cell Phone battery. I know you could get 12v-14v packs back then. It would have to be wired into the system with a diode of some sort so that the voltage could charge from the alternator but not discharge into the starting system. This would keep the power to the needed circuits but not flow into the rest of the power system in the car. If it could be made small enough to tuck away say next to the ECM. It would not even be a handy to have it there. Would be really nice to have it there in a pinch. I know the wicked 2800mah energizers come with a 12v charger for the car. They can be put in the charging system them left there. The chargers brings them up to capacity then leaves them until they naturally start to drain and then filles them up. I think they actually make 1.5 per cell so you'd only need a total of 8 cells to make a nice strong 12 source.

As far as I can remember the trunk pop, stereo memory, cig lighter are all on the same circuit. If you mounted the battery in the space, above below or around the ECM it would be a simple matter of hooking into the cig circuit, then finding out what is the ECM power slot and plugging into there as well.

I have got a good battery in my car, 1000ca with a 140amp Caddy alternator, but I find myself having a reason to disconnect it on more than a few occasions recently. Getting welding done on the car, cleaning wires, even removed the battery and loaned it to my mother to get her car home in a pinch when the alt quit. (you can drive for quite some time on a large battery during the day on battery alone if you turn off all the extra stuff)

So you see where I am coming from and what I want to do.


Anyone got any suggestions or has this been done before. I think if you set this up right, you could even rig it so that an over voltage or other major electrical fart could be absorbed by the battery. Might even save an ECM or other device.

I am not saying wire it in-line, but in parallel with the current system.


Anyone suggestions guys or gals. This could save us. Just think never having to tweak with your messed up radio, or driving the car running for a bit until the ECM learns. Could really be good.
------------------
85GT 5spd ,93 Eldorado 4.9 Dual O2 Custom Chip, Archie Clutch. Custom Exhaust. MSD Everything 245/50/16's Not Your Average 4.9 Capt Fiero Com --- My Over View Cadero Pics

[This message has been edited by Capt Fiero (edited 06-20-2006).]

ever been to Sears to get your battery changed? they have exactly what you speak of. basicly a 12v sealed lead acid battery, which can be found in most "EXIT" signs over doors, or bought for $25. and they have a cigarette lighter jack hanging off them. then plug it into the cig lighter while the swap out the battery to save all your settings. and, they are 12v sealded lead acid (same as car battery), so charging them is just leaving them plugged into the cig lighter.

so - heres what ya want to do: when you see a "EXIT" sign over a door, or saftey fire lights, there will be a "test" button - hold it down - if the light works, the battery is good. take that battery, and connect a cigarette lighter adapter from some broken automotive knick knack, and wire it onto the battery - some have fuses in the adapetr, if not, and inline fuse is good. the center post is +
you now have battery backup.

But I want something that can be mounted permantly. Set and forget type of deal.

------------------
85GT 5spd ,93 Eldorado 4.9 Dual O2 Custom Chip, Archie Clutch. Custom Exhaust. MSD Everything 245/50/16's Not Your Average 4.9 Capt Fiero Com --- My Over View Cadero Pics

quote Originally posted by Pyrthian: so - heres what ya want to do: when you see a "EXIT" sign over a door, or saftey fire lights, there will be a "test" button - hold it down - if the light works, the battery is good. take that battery, and connect a cigarette lighter adapter from some broken automotive knick knack, and wire it onto the battery - some have fuses in the adapetr, if not, and inline fuse is good. the center post is + you now have battery backup.

You ALMOST forgot to mention to leave a note saying "the battery from this exit sign is missing", so the maintainence people can replace it, so if/when there is an actual emergency, that thing will light up!

*pokes ya in the medulla*

I bought a backup for my alarm. Haven't hooked it up, but it's not complicated. It's a 9V battery and a diode I believe(I'll dig it out and check if you want). I bet a 12V alarm remote battery would work better.
Or you can do this:
http://www.jcwhitney.com/autoparts/ItemBrowse/c-10101/s-10101/p-100000224478/mediaCode-ZX/appId-100000224478/Pr-p_CATENTRY_ID:100000224478

[This message has been edited by Joe Torma (edited 06-20-2006).]

I plan on doing a similar mod, using one of the new gel batteries, with two exceptions: a voltage sensor circuit to disconnect the backup from the main system when the voltage drops below a certain point (used to have one of the Sears DieHard Security batteries; that was one of the major advantages--- when something, like a dome light left on, drained your battery, you hit a button on a remote, the system reengaged, and you started up and drove away. Handy for husbands whose wives always left headlights on.).
I also plan on installing an external set of power terminals for maintenance purposes (periodically you should put a deep charge on your car's battery to prolong its useful life) similar to those used on boats.

Another useful mod would be an external master power interrupt switch, for the purpose of killing the entire electrical sytem in an emergency.

[This message has been edited by Vonov (edited 06-20-2006).]

You need a thing called a "dual battery isolator" it will charge two batteries from the alternator but not draw off of both. The only real way to do an alarm is to have a seprate battery for the alarm. It also helps with car audio so you can drain your battery playing music and then still start your car.
You can even find one in most auto parts stores.

Most car audio stores also have small sealed batteries to mount inside the car just for such a thing.

------------------
"DRIVE IT LIKE A FIERO"
'84 Fiero, engine to be determined
'87Blue GT 3.4L Swap Completed!!!!!!!!
http://www.lasvegasfieroclub.com/

[This message has been edited by sardonyx247 (edited 06-20-2006).]

Might be easier to get one of these.



Just plug in the cord to the lighter. Got this for under 20 bucks.

Plus for you Sardonyx...thanks for the tip on the isolator.

quote Originally posted by Pyrthian: basicly a 12v sealed lead acid battery, which can be found in most "EXIT" signs over doors, or bought for $25. and they have a cigarette lighter jack hanging off them. then plug it into the cig lighter while the swap out the battery to save all your settings. and, they are 12v sealded lead acid (same as car battery), so charging them is just leaving them plugged into the cig lighter.

Most of the exit/emergency light batteries are not 12 volts, they are 6 volts. You'd have to run 2 of them in series or purchase a 12 volt backup battery ( many computer power backup systems are 12 volt batteries ), but they aren't cheap. A 6 volt 12 amp hr battery at Batteries Plus runs bout $18, so 2 would be $36. They are a little cheaper at Home Depot, but not much. So, for $30-40, you can get a 12 volt battery backup for your car, but why not just get a cheaper car battery which will last longer ( roughly 4 years compared to 2 years for the backup batteries ) and have a lot more amps.

You'd be better off just hiding a key under the bumper.

Both of those setups are pretty much the same thing.

However a 9v battery is not going to cut it for my alarm on my car. ( 4 sirens relayed straight from battery 12v signal)

I don't want something that gets plugged in only when needed. I want a permanent solution. Something that would be there even when I did not think I was going to need it.

Remote cutoff is another thing I want to add to the car at some point. That way when you need to disconnect the battery it is a matter of turning a handle.

I need an electronics guy to explain the part I would want. I thought it was called a diod pack? Allows power to go in, but not out. The alternator could charge it, but not draw power back through the same direction.

[This message has been edited by Capt Fiero (edited 06-20-2006).]

Did you see my post above? It says exactly what you need.

quote Originally posted by Firefox: You'd be better off just hiding a key under the bumper.

Huh?