A requested jury instruction must be given on every material question "upon which there is any evidence deserving of any consideration whatever . . . . The fact that the evidence may not be of a character to inspire belief does not authorize the refusal of an instruction based thereon. . . . However incredible the testimony of a defendant may be he is entitled to an instruction based upon the hypothesis that it is entirely true." (People v. Burns (1948) 88 Cal.App.2d 867, 871, 200 P.2d 134.) Contrariwise, an accurate instruction may be refused if there is no evidence to which it may properly relate. (See People v. Haag (1954) 127 Cal.App.2d 93, 97, 273 P.2d 328.)
For subscription based briefing and sample instructions on this and related issues see:
Forecite National™
Chapter 250: Defenses And Defense Theories: General Issues
250.1 - Grounds For Instruction On Defense Theory
250.4.2 - Defendant's Right To Directly Relate The Defense Theory To Prosecution's Burden
The Shellow Instructions
Defense Theory
Forecite California™
PG X(C)(3.1) - Failure To Instruct On Defense: General Instruction On Element Of Charge Is Insufficient