What is the test for voluntary manslaughter based on use of excessive force in self-defense?

Voluntary manslaughter based on use of excessive force in self-defense, however, is not a separate theory from voluntary manslaughter based on imperfect self-defense. (See People v. Mayfield (1997) 14 Cal.4th 668, 777.) Where a person uses excessive force in self-defense, malice is negated only if defendant honestly but unreasonably believed that the degree of force used was in fact necessary. (Ibid.) By virtue of CALCRIM No. 571, the jury was adequately instructed on this theory, and they rejected it. In considering whether defendants unreasonably believed they needed to use deadly force, the jury necessarily considered whether the force Guzman used was excessive, and hence unreasonable. There was no need for further instruction on excessive force.

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