I've heard from several people that I can use a diode to connect a second small sealed lead acid battery to my PC. I was out shopping yesterday and I saw this small battery charger meant to be connected to a solar cell, it can be seen here.




Basically if the input voltage (from the Cars electrical system) is above 13 volts it will allow current to pass to the small sealed lead acid battery, if the system gets to 14.2 volts it will stop charging the battery.

What are your thoughts on using this device to maintain charge on the small sealed lead acid battery and also allow me to run my PC during startup?