nsxxtreme, I did actually contact DEI as well and this was their response- “Our run of the mill alarm systems have a current draw of approximately 17-20mA. A GPS enabled SmartStart adapter will pull around 40-42mA. This means you will have a combined current draw of approximately 60mA. A healthy car battery will last about 5 days with that kind of current draw (without being driven).”
Based on that draw alone, I think they are a little conservative on their estimate of how long a battery can last without being driven. However, they probably realize that many of their customers who install their alarms generally do it to protect other valuable accessories, like aftermarket stereo systems, which will also increase the draw and decrease the time a vehicle is able to sit without having a charge to the battery.
Jim McIlvaine
eCare Manager, OPTIMA Batteries, Inc.
www.facebook.com/optimabatteries