Evaluations Involving Battered Women: What Does Psychological Research Tell Us? Family Law Quarterly vol 39, no. 1, p. 87-108.

Evaluations Involving Battered Women:  What Does Psychological Research Tell Us?  Family Law Quarterly vol 39, no. 1, p. 87-108. 
Erickson notes:

The effects of domestic violence on survivors, who are primarily women, may be severe. Battered women's advocates often note that, in custody cases, the batterer often "looks better" to the court than the victim does because he is confident and calm, whereas she is still suffering the effects of his abuse and therefore may appear hysterical, weepy, anger, or otherwise not "together."
When a custody evaluation is conducted by a psychologist, the revised version of the Minnesota Multiphasic Personality Inventory (MMPI-2) is often used as part of the evaluation process. The MMPI-2, like other traditional psychological tests, was not designed to be used in custody evaluations and arguably should not be used for such purpose except "when specific problems or issues that these tests were designed to measure appear salient in the case."

If it used, Erickson notes that "great care must be taken" as "a misinterpretation could result in placing custody of a child with a batterer, which could put the child at severe risk."
Erickson reviews research on the use of MMPI evaluations with battered women and found that that the psychological stress that battered women suffer may result in MMPI scores that do not accurately evaluate their ability to parent.
http://www.leadershipcouncil.org/1/pas/dv.html