Extreme mass ratio inspirals (EMRIs) are excellent sources for space-based observatories
to explore the properties of black holes and test no-hair theorems. We consider EMRIs with a
charged compact object inspiralling onto a Kerr black hole in quasi-circular orbits. Using the
Teukolsky and generalized Sasaki-Nakamura formalisms for the gravitational and vector
perturbations about a Kerr black hole, we numerically calculate the energy fluxes for both
gravitational and vector perturbations induced by a charged particle moving in equatorial circular
orbits. With one-year observations of EMRIs, we apply the Fisher information matrix method to
estimate the charge uncertainty detected by space-based gravitational wave detectors such as the
Laser Interferometer Space Antenna, TianQin, and Taiji, and we find that it is possible to detect
vector charges as small as q ∼ 0.0049. The results show that EMRIs composed of a Kerr black
hole with a higher spin a and lighter mass M, and a secondary charged object with more vector
charge give smaller relative error on the charge, thus constrain the charge better. The positive
spin of the Kerr black hole can decrease the charge uncertainty by about one or two orders of magnitude.