Vampires lose no motives at night. If awake and indoors during the day, motives drain at 1000/day which is just over 40/hour. If awake and outdoors during the day, motives drain at 5000/day which is over 200/hour so a vampire can drain an entire motive bar in an hour.

Social drains at 500/day during the day regardless of whether the vampire is inside or outside.

If you manage to make a pre-teen vampire, the sim will suffer normal (not vampire) motive drains at night or when inside during the day, but the super-fast motive drains outdoors during the day.

On commercial lots, vampire energy drains slows down to 240/day (or 10/hour) once energy drops to -90. If outdoors energy can't go below -90, but if indoors energy will drop past this level (which is probably a bug). Again this is only on commercial lots.

Motive drains don't differ by age or pregnancy.

If a vampire is on a livable lot and all of hunger, comfort, energy, fun and hygiene fall to -90 or below, the vampire dies. Swimming vampires will drown rather than burn up in the sun.

It should be noted there is no actual check for daylight so this could even happen at night in a windowless room should the vampire's motives fall for some other reason.

There is no age check for death. Pre-teen vampires are normally impossible, but if you get one be careful. Motive drain is so fast outdoors, child and younger sims might die even before the social worker arrives.