Your smart phones have their own internet access, so I'm guessing you have additional internet needs, e.g. a tablet, laptop, or whatever. You said a phone hotspot doesn't last long, but that's just a matter of adding a power source or more data to your plan (see Matt_C's reply). You can use a dedicated internet hotspot (often called Mifi after a product of that name) but it too needs a data plan and power to operate. You can also use an old smart phone as a dedicated hotspot if you add it to your plan. But all those things cost extra money. If you are asking about no-cost internet on the road, the only answer is to stop within range of a restaurant, store or public library that has open wifi.