While conversion rates will vary, cart abandonment emails work best if they are sent within an hour of abandonment. It is also good practice to send another email in a day, and another within a week. You should test the exact timings, as well as remember to cancel the campaign once a purchase has been made.
Also consider testing a discount or free shipping to close the deal. Users often go through the entire purchase flow to see the final price and then compare it to other stores’ prices or go hunting for a coupon code. Obviously, the emails should link back to the cart but you’ll want to test the CTA.
If dev resourcing is an issue, explore turnkey solutions like Ve. While this will still involve inserting a couple of lines of code onto your site – it might be a lot simpler than coding something in-house from scratch.
Finally, explore pairing this with a retargeting campaign to maximize results.