Kickstarter Question - Crowdfund for a series?

I’m considering doing a Kickstarter campaign. I’ve written a three time-travel romance book series. I guess it would be considered a serial. Each book ends with an HEA for a couple, but there’s an overarching story and mystery that only ends/solves in the third book. My question is, would I do the Kickstarter for Book 1 only or all three as a series? Thanks for your help.