What phone with a GPS has the longest battery life while using the GPS?

I'm looking for a phone with a built-in GPS, but the battery life is important to me. Many manufacturers claim many hours of battery life, but enabling the GPS will suddenly leave you with just a few hours of battery life. Are any phones known for having good battery life, even with the GPS enabled?|||the motorola devour, im a florist, and i use it to direct me where i gotta go lasts 8-10 hours, and its made out of aluminum so if u drop it, nothings gona happen