i have an opus 150 and use the standby option. while this gives me a fast startup time, i get nervous when i don't drive my car for a couple of days because i know my battery is getting drained. i've been doing a lot of reading about different options people here have been using with wheelchair batteries, isolators, diodes, etc. i am wondering if it would be a good solution to get a small wheelchair gel battery and hook up the opus to it instead of my main battery.

in this case would i need to get an isolator to charge the gel battery or could i just use a switched 12 volt line like the cigarette lighter to charge the gel? also when the car is on would the carputer's power be drawn from the battery or would it come straight from the alternator?