I am a Breton battle Mage and the robes are too weak during fights so I will enchant an armor set but which is better light or heavy

I'd say heavy - in Oblivion, all of the armored battlemages wore heavy armor.

I agree. Heavy armor have been the armor they have commonly been portrayed with since Morrowind.

I've done both. Heavy is traditional but it's all about looks.

I once had a battlemage that wore light. A battlemage in leather armor is lame. In scaled armor: lame. Glass armor... okay as long as the character's female. But a Battlemage in Dragonscale looks awesome. The only problem with that is that usually by the time you reach that level the character's begun to wind down and you're thinking about the next one.

Have you tried Alteration magic? Alteration is quite an easy magic to level up in by casting simple smaller spells as your character roams around.

Perk up the alteration tree and you'll see that alteration protection spells become massively stronger if used by a character not wearing any armor.

My Breton witch uses clothes with alteration magic. For attacking she uses her left hand for alteration or summoning a creature to fight then conjures a battle axe with her right hand which then gives her a two-handed attack with the partial ability to block (2-handed weapon block).

I was able to put a majority of my levellig points into magicka this way.

I'd personally use Alteration instead, but if you must have armor then I guess heavy would make more sense for a Battlemage. Dont wear a full set though. Helm, shield and gauntlets aren't needed.

Depends on what you prefer if your character is proficient in Smithing. If you keep smithing weak, then definitely go heavy. My main character is mainly a spellsword, but sometimes he goes all battlemage while wearing legendary Dragonscale armor. It's a good feeling.