recommendation on a portable battery charger for a 08 Escalade
 

I am looking to buy a portable battery charger to keep in my truck in case of emergency. I live in Michigan so it gets pretty cold and I leave my car in drive way for weeks at a time.

What is the minimum cold cranking amps I should be looking for?
What would be the optimum AMP capacity I should buy? 350? 500? 1000?
Any specific make and model you guys would recommend?


I was thing about the Stanley J5C09 500-Amp Jump Starter with Built-In Air Compressor