Here's a helpful article from Computerworld on how to improve the battery life on all your Apple devices. Here's one example, which I wasn't aware of, and just now did, that reduces the amount of 'juice' drawn from your iPhone: switch off AirDrop. I never use this feature, and it has been just sitting there, hour after hour, sipping 'juice' from the battery on my iPhone!
There are other tips in the article that may help keep your devices from losing battery life so quickly. Read the article to find out more.