PersistentCart keeps the items that your customers have added to their cart forever. Here is a sample of how it works. Let's say your potential customer Alan wants to buy your cool merchandise. He logs in from his laptop and adds a couple of items to his cart. He has an emergency call and closes his browser. The next day he is ready to purchase, so he comes back to your store but finds out that his items are not in his cart any more. Agitated he leaves your store and you lose a customer. Persistent cart solves this problem.
For optimal effect we recommend using PersistentCart with AbandonedCarts
PersistentCart for OpenCart comes with extensive documentation with images, installation instructions, features explanations and examples.