This Halacha is an excerpt from our Sefer
1. Havdala Motzei Shabbos Tishe Beav:
Havdala over wine is not recited on Motzei Shabbos, it is rather recited on Sunday night. [See below for the relevant laws of Havdala on Sunday night].
Meorei Haeish: One is to recite the blessings of Meorei Haeish on Motzei Shabbos upon seeing a candle. One is to recite the blessing prior to Eicha. [Some write that one may recite the blessing any time prior to Eicha, and hence if one is home prior to Maariv, he may say the blessing at home with his family and fulfill the obligation with them. Practically, the custom is like the former opinion to recite Borei Meorei Haiesh in Shul after Maariv, prior to Eicha. The women at home are to recite the blessing over Meorei Haeish on their own. Some write one is not to use the regular Havdala candle for Meorei Haeish but is rather to join to small candles together.] In the event that one did not recite the blessing of Meorei Haeish before Eicha it is to be recited afterwards. If the blessing was not said at night, it may not be said the next day.
Besamim: The blessing of Besamim is not said at all, not on Motzei Shabbos or Sunday night.
Are the Pesukim of Hinei Keil Yeshuasi recited on Motzei Tisha B’av which falls on Sunday?
Q&A on those who eat on Tisha B’av
Must one who is not fasting say Havdala prior to eating?
What is the Seder of Havdala in such a case? One omits the versus of “Hinei Keil Yeshuasi”, and rather begins from the blessing of Hagafen or Shehakol [depending on his beverage]. The blessing of Besamim is omitted. If Havdala is being recited on Sunday, the blessing of Haeish is likewise omitted and is supposed to be said the night before.
Is wine to be used or Chamer Medina? Some Poskim rule one is to use wine or grape juice. Others rule one is only to use Chamer Medina, such as tea or coffee. If there is a child available which has not reached the age of Chinuch for mourning but is past the age of Chinuch for blessings, one may say Havdala over wine and give him to drink.
May one who needs to say Havdala in order to eat be Motzie one who is fasting?
If one’s wife needs to eat, may her husband say Havdala for her and have her drink the beverage?
Yes. Some write it is proper to do so in order for him to approximate Havdala to the leave of Shabbos as much as possible, rather than delay it until Motzei Tisha B’av.
Are children who have reached the age of Chinuch to say Havdala prior to eating?
Some rule children are to say Havdala prior to eating. Others rule they may eat before Havdala and are to hear Havdala on Motzei Tisha B’av with their father.
May an adult say Havdala for his children and have them drink the wine?
The custom is not to do so.
2. Sunday night-Motzei Tisha B’av :
Havdala when Tisha B’av falls on Motzei Shabbos:
In the event that Tisha B’av falls on Motzei Shabbos, Havdala over wine is recited on Motzei Tisha B’av, which is Sunday night. The blessings of Besamim and Haeish are omitted from Havdala. One is to recite the blessings of Meorei Haeish on Motzei Shabbos upon seeing a candle. The blessing of Besamim is not said at all, not on Motzei Shabbos or Sunday night.
The Nusach of Havdala: On Sunday night, one begins Havdala from “Hinei Keil Yeshuasi”.
Eating and drinking: It is forbidden to eat and drink after Tisha B’av until one says Havdala over wine, just as is the law on Motzei Shabbos. It is permitted to drink water although our custom is to avoid doing so.
Who is to drink the Havdala wine?
Some Poskim rule one may drink the wine of Havdala himself. There is no need to give it to a child to drink. Others however rule wine should not be used, or is to be given to a child, just like on Motzei Shabbos Chazon.
The mourning customs: 
In the event that Tisha B’av and Shabbos coincide, and hence Tisha B’av is differed to Sunday, the custom is to not to eat meat or drink wine throughout the night of Motzei Tisha B’av [Sunday night]. See the list below regarding other mourning customs. The next morning [Monday] all the mourning customs are permitted.
The following mourning customs apply until sunrise of Monday:
The following customs are permitted immediately on Sunday night, Motzei Tisha B’av:
May one have marital relations on Motzei Tisha B’av that was pushed off to Sunday?
Some write one is not to have marital relations that night. Likewise, some write that for health reasons one is to never have marital relations after a fast. Practically, on night of Mikveh one may have marital relations at this time.
May one have a wedding on Motzei Tisha B’av that was pushed off to Sunday?
Some say in a time of great need it is permitted to do so.
 Michaber 556:1
Other Poskim: Some Poskim rule there is no Havdalah recited in a year that Tishe Beav falls on Motzei Shabbos. [Ramban; Reiah; Ritva Sukkah 54; Rashba]
 Michaber ibid; Maharitz Geios Havdala; Mordechai Taanis Remes 638; Orchos Chaim Havdala 1; Sifrei Minhagim of Rishonim
 Taz 556:1 in name of Beis Yosef 556 in name of Abudarahm p. 69; Elya Raba 556:2; M”B 556:1
The reason: As in Eicha it says “he has placed me in darkness”. Hence the blessing is to be recited beforehand [as afterwards we are to emphasize darkness]. [Taz ibid] Alternatively, the reason is because one is not to read Eicha with light and hence benefit from it prior to saying a blessing over it. [Birkeiy Yosef 693:1] Practically, however, we do not rule this way, and it is permitted to benefit from light before saying Meorei Haeish. [Kaf Hachaim 556:2; See our Sefer “The Laws of Purim” and the “Laws of Motzei Shabbos”]
Other Opinions: Some Poskim rule one is to light the candle at home after coming home from Shul after Eicha. [Maharil Tisha B’av 16; Many Poskim, brought in Elya Raba ibid]
 Piskeiy Teshuvos 556:1; Nitei Gavriel 95:4; Hiskashrus 940; Likkut of Rav Braun
 Sheivet Haleivi 7:77 “One is not to swerve from the Minhag Yisrael that everyone says:hears the blessing in Shul prior to Eicha and the women are to say the blessings themselves at home”; Luach Kolel Chabad; The Rebbes custom was to say Meoreiy Haeish in Shul after Maariv, prior to Eicha; Rav Eliyahu Landa that so was always the custom, to say it in Shul after Maariv and not at home prior to Maariv. Rav Groner confirmed the custom is to say it after Maariv, before Eicha.
The reason: See Tehila Ledavid 293:1 and Kitzur Halachos Shabbos p. 119 that one is not to say Havdala, which includes Meorei Haeish prior to Maariv; [In however the Sefer Pear Yisrael 1:207 he writes that the Alter Rebbe at times would say Havdala prior to Maariv.] Perhaps this is also due to the law of Kadima of Tadir, as Maariv is more Tadir. [See The laws of Chanukah regarding Chanukah candles versus Havdala and Bedikas Chametz and Sefiras Haomer regarding preceding Maariv because of Tadir] Likewise, it is improper for men to do Melacha before Maariv, even to light a candle, as brought in Admur 299:20, however if done for a Mitzvah it is allowed, and here too it is done for a Mitzvah. Likewise in any event Eicha is before Ata Kadosh.
 Shevet Halevi ibid; See Ketzos Hashulchan 96 footnote 12; So rules also Daas Torah 296; Ben Ish Chaiy Vayeitzei 24; Kaf Hachaim 296:54; Igros Moshe 2:47; Kinyan Torah 1:88; Beir Moshe 4:28; Kaneh Bosem 3:17; Sheivet Haleivi 6:42; 7:77; Yechaveh Daas 4:27; Ashel Avraham Mahadurah Tinyana; So is proven from Admur who does not mention anywhere any differentiation regarding women in the blessing of Meoreiy Haeish. Furthermore, even according to those Poskim [M”B in Biur Halacha 296 “Lo Yavdilu Leatzman”] who side women are exempt from the blessing of fire, they are nevertheless permitted to say the blessing as is the law by all Mitzvos that they are exempt from. [Ketzos Hashulchan 96 footnote 12]
 Piskeiy Teshuvos 556:1
 Taz ibid; Elya Raba ibid; P”M 556 M”Z 1; M”B 556:1
 Admur 299:9
 So writes Hiskashrus 940 footnote 82 to be custom of the Rebbe. This dispute seemingly follows the same dispute regarding if these verses are to be recited on Motzei Yom Tov.
 Mateh Ephraim 581:181; 601:10; 624:5; SSH”K 62:44; In Luach Kolel Chabad it states one is to say Havdala like the order of the rest of Jewry which is to skip the verses of Hinei Keil Yeshuasi
 Kneses Hagedola 2:71; Birkeiy Yosef 556:3; Zechor Leavraham 556:9; Shaareiy Teshuvah 556:1; Moed Lekol Chaiy 49; Kaf Hachaim 556:9
 As accoridng to amny Poskim women are obligated in Havdala
Other opinions: Some Poskim rule that women are not obligated to recite Havdala prior to eating/drinking on Tisha Beav. [Ashel Avraham in Ezer Mekadeish]
 Divrei Malkiel 6:9; Piskeiy Teshuvos 556:4 as is the ruling by an Avel; Regarding an Avel-see Pischeiy Teshuvah 376:2; 391:1 Piskeiy Teshuvos 296:6
 Birkeiy Yosef ibid; Shraga Hameir 7:71; Az Nidbaru 11:48
 Kaf Hachaim 556:9; Minchas Yitzchak 8:30; Kinyan Torah 2:111
 Kaf Hachaim ibid
 Kaf Hachaim 556:9
 See Piskeiy Teshuvos 556:4 for a list of Poskim which deal with this issue and their reasons.
 See Piskeiy Teshuvos 556:4
 Michaber 556:1
 So writes Hiskashrus 940 footnote 82 to be custom of the Rebbe. This dispute seemingly follows the same dispute regarding if these versus are to be recited on Motzei Yom Tov.
Other Opinions: In Luach Kolel Chabad it states one is to say Havdala like the order of the rest of Jewry which is to skip the verses of Hinei Keil Yeshuasi. So rules Mateh Ephraim 581:181; SSH”K 62:44
 M”B 556:3 in name of Degul Merivava; Piskeiy Teshuvos 558:3
 Peri Megadim 556 A”A 2; Aruch Hashulchan 556:2; Luach Eretz Yisrael of Harav Tukachinsky
 Rama 558:1
 The reason: As the night is an extension of the mourning which took place during the day.
 Rama ibid
 Rama ibid
 Other opinions: Harav Tukachinsky in Luach Eretz Yisrael writes that all the mourning customs apply until Monday morning. The list below does not
 Shaareiy Teshuvah 558 “Assur”; M”B 558:4
 SSH”K 62:49
 SSH”K 62:49
 Piskeiy Teshuvos 558:3
 Shaareiy Tziyon 558:4 regarding the meal of a wedding; brought in Piskeiy Teshuvos ibid
 Daas Torah 558; Maharsham 4:148; Sheivet Haleivi 6:70
 Shiyurei Kneses Hagedola on Tur 240
 Kaf Hachaim 558:7
 Piskeiy Teshuvos 558:3