installing 2 alarms with 2 batteries

The sell car alarms that have backup batteries just for occasions like these. These are usually 9V batteries, but it can be replaced with a bigger 9V-12V battery. No need to go through all that trouble. You can also install more sirens, including ear shattering piezo speakers inside the cabin. It is amazing the amount of things you can do with alarms now a days!

No need to reinvent the wheel man, just go speak to a competent alarm shop, or search on line.

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installing 2 alarms with 2 batteries

ok, after having my car broken into twice, i came up with a plan. i'm going to install 2 alarms. the first one is my fm2009 2way pager alarm. the second one is a crimestopper super rage. i will use the negative armed output wire from the 2way with a relay to give the second alarm power or not.
so, i can arm one, and then the other one. when i goto disarm, it will cut the power from the second one, so it will be disarmed. too bad i can't find a second alarm system that would let me arm and disarm using wires and not a second remote and cutting the power, ghetto way, but it should work. this second alarm would be hooked up to another shock sensor and my hood, door, and truck negative inputs. it would have a seperate siren too. i'm planning on mounting it under the back seat.

but i was thinking, if they really wanted to get my car, they could just cut the wires from the battery. so i decided that it would be best to run a second, preferably smaller 12 volt battery. i know that if i use a motorcycle battery, it won't last more than a couple of days, and then it will need to be recharged, right? do, could i get a voltage regulator and hook it up to the alternater so that it will charge both batteries and not have the one battery steal voltage from the other?

crazy idea, i know, but i'm tired of getting broken into and not having that secure of a system.

also, if i hook up my amps to the secondary battery, it wouldn't take power from the engine and my headlights would dim, without the use of a capacitor

ok, i was going over my design in my head. if they cut the main power wire, it would disable the main alarm, which would no longer output a negative to the second alarm and it would shut off the second alarm. so, i would either have to setup a relay system that would use the first alarms negative pulse for factory lock/unlock to turn on a relay to 12volts till it gets the signal again to turn it off.
i found this on the 12volt.com
http://www.the12volt.com/relays/page5.asp
if i use the latched on/off one, it would work, just alot of relays to hookup

i also found this: http://www.autotoys.com/x/catalog/B...RMS_p_1288.html

it's a 1.2 amp battery. i could hide it by the airbag on the passenger side, up under the dash. i belive it charges from your main battery.

also, i'm looking to get this:
http://asianwolf.com/item.jhtml;$se...36&PRID=1354125

it is a battery backup siren