Go go TEC!  One thing you might try to throw a little more focus into is befriending another faction.  Around 50% friendship, or maybe it's exactly 50%, you (or they) can offer a cease fire, which helps TREMENDOUSLY since you're going solo. I've found the AI likes to team up on you even though they're not necessarily teamed up when you start the game.

Many people say build hangars n' stuff, but all I ever do is make a very tight clump of 2 repair bays and fill in the rest with nothing but turrets.  That can and will keep them busy for a good amount of time.  Make your turrets focus fire those important units (repair units, carriers if they come in range, etc.)  I say carriers because the only way you're going to stop strikeforces is by killing the host and letting them slowly drain out.  Either way, I've never really found planes to be much of a problem doing the all turret defense strat.

I don't know if you created your longest trade route you could, but if you didn't, that is a SIGNIFICANT income boost. 

If you can muster up a force big enough at your choke point, they probably won't invade.  AI is weird about that.  Seems they are somehow all-knowing when it comes to knowing what's in a grav well and what isn't.  If they see 30 turrets and a decent sized fleet, chances are they won't even invade.  That would enable you to further build your fleet until you're ready to rain down destruction on them!

Good luck, and remember to micro-manage your cap shits and little frigates to kill key enemy units!

3 lvl 6 MARZA cap ships(geuss why lvl 6^^)

2 Dunnov cap ships

10 carriers witha few bombers + lots of fighters ( they are not supposed to kill stuff just draw the AI strike craft)

10 HOSHINKO(TM)

3 repair bays and lots of hangers and you can take out the AI fleets(this will work untill endgame super fleets, at that point you will need more)

Anyway, it souds like you set the AI plyers as 1 team, tr splitting them into 2 teams, if you win make 1 team stronger if you win go back to just 1 AI team. should give you a little more room to act.

and remember to MICRO your cap ships abillities! The main offencive power of TEC is it's capships(read MARZA)

Finalyy, when playing the AI don't worry about taking out the first AI world you attack--> if you win and he retreats his fleet go after him instead of conquring if you keep doing that, you will end up with a supirior fleet at his homeworld--> now conquer that! this will break him 9 out 10

hope it helps

I've had the same problems with TEC. They lose loads of their ships in massive battles, but as pointed out above they have a great capacity to continually replenish their losses with their solid economy.

1. Befriend at least one of the AI. It goes a long way towards allowing you to focus on one opponent at a time.Even if it costs you 1000 credits and a couple hundred metal or crystal, getting to that 50% approval is key. They almost always will accept a ceasefire at that point and it takes a huge weight off your military by allowing you to move into an offensive mode agains a target of your choosing.

2.The Marza Cap Ships are devastating late in the game, so train them up early and often. Once it reaches level 6 its a fleet-killing powerhouse.

3. It doesn't hurt to throw a small attack fleet of Javelin or Cobalts at an enemy early on. Harrass them by destroying constructors on a newly developed world, of by taking down one of their colonizer ships. Just keep the AI guessing and be sure to retreat when you need to as well.

One things that has really helped me in games is to make sure you capture a second planet very quickly. Asteroids are nice and easy because they aren't as well defended, but they are very limited with logistics slots which you need for Military or Civilian Labs. Gotta have those so you can get your Kodiaks! These are TECs best combat cruisers and you want them ASAP. 3-5 Kodiaks surrounding a planet with a couple repair bays and some Defense Platforms are quite capable of holding off full size fleets of pirates or early enemy invasions. Later in the game you'lll defenitely need to beef your fleets up with some good balance and make sure you throw in those Hoshikos to keep your fleets alive. "Such an elegant design".

I'm a noob to Sins as well, but its a great game that keeps me hooked and coming back for more. Don't get frustrated if you have to take your lumps along the way! I've actually played a game for several hours built up a huge fleet with 4 or 5 cap ships went to invade an enemy world only to have all my Cap ships and my "super" fleet wiped out in under a minute. Thats disheartening but it gets easier each time.

I posted a similar thread here a week or two ago and got some real good advice for TEC as well. https://forums.sinsofasolarempire.com/332027

Happy gamin!

Fully upgraded TEC repairbays are cheatingly good

tou are missing a few key points

1. it does not matter where you producction is located after the 1'st ship arrives, after that the get there as fast as if you had a factory on the planet you are attacking

2. the AI is utter stupied-- split your offenciv fleet in 2 -- 1/3 and 2/3 -> start up production and set the new ships to move to some planet(best if you can find the planet with his main fleet) when buit -> just before the first start appering jump in the small fleet. As long as you have the econ his fleet will not move .... dossent matter if he kills 20-1 just keep pushing. then jump your big fleet to another planet/astroid(astroid is better as you are just in it for the beachhead, grats on your *free* new colony -> now get your culture startd as what is really keeping defenciv advent fleets up is lol 25% start migitation instead of 15.

As soon as you have a foothold the AI in that system is effectivly dead in the water, he'll keep trying to take your beach but as you allrdy know TEC repairbays > enemy fleets

remember entering a new starsystem is akin to D-day, screw the loses but get that beach head at any cost.

And NEVER underestimate the firepower of 3 lvl 6 marza's missile barrage - 3x3000 dmg will kill ANY fleet it faces even a maxed out advent fleet

Edit:

part1 remember the small fleet is not meant to kill but to survive, lot's and lot's repair cruisers

part2 time your attack with getting the pirats on him for extra help

one thing you "might" try, though I'm not sure if this will work, is to move away from the advent when you see all their guardians trigger.  If you don't know specificially what that is, it's the GIANT halo-like glowing ball of energy that fills the battlefield.  Very hard to not see.  This can be considered a video card killer too!  

Anyhow, when you see all that stuff fire off, try moving your fleet away "out" of that aura, so that their fleet is no longer in it.  Doing so will make your damage not get split up and you can actually kill stuff.  I've never really tried this, but the ships might be to slow or to sluggish to use this effectively.  Worth a shot though.

If you see a proginator, it must die first, it's the big flying triangle ship.  It uses malice (can be a VERY highly damaging fleet attack) and shield recharge, which recharges like 67 shield points/sec to everything in it's radius at lvl 3). 

You can try creating like 30-40 percheron carriers, and loading them all up with bombers.  Soon as you see the advent fleet, target all your bombers on the cap ship.  It won't be living for very long!

Edit:  I also wanted to throw this in there since it's over-looked by newer players.  The Vasari.  Build two space eggs, amass your fleet and go rape an enemy fleet.   When they start to flee, fire off one of those gravity balls into their fleet before they phase jump.  As it wears off, be ready to fire another with your other space egg.  Basically, the enemy fleet is screwed since they can't phase jump away and they won't even be attacking back since they're trying to escape.  It's one of those things that makes the vasari so dangerous besides the phase stabalizers and the RA.

Others have mentioned the Marza. I can't emphasize that enough. Missle barrage has been so effective in the latest patches that I started using Marza's almost exclusively. In my latest game, all of my cap ships are Marza's, except for 1 Akkan in each fleet for colonizing and ion bolt, and 1 sova for strike craft support(it's fun seeing the enemy destroy all 6 of your bomber squads, only to have Rapid Manufacture instantly rebuilt them). I actually started having a new problem, the enemy fleet would run away after like 20 seconds of combat because of the terrible damage that Missle barrage did. Of course ion bolt helps in that situation so you can still pop their retreating cap ships. I would even send a handful of marzas off alone to hold of an entire enemy fleet and when the missle barrage ended my ships where the only ones left standing. Raze planet is also nice for taking their planets down fast.

It is a single target ability, but when it hits that target, it affects all those around it.  Sorta like malice where you target one ship, but it affects many.  It has a decent area of effect after it hits too.  Makes for easy pickings!

Depending on how clumped they are, one gravity warhead can literally stop hundreds of ships from phase jumping.

I guess my wording wasn't clear enough. What I mean is you can keep building ships and sending them to the gateway worlds on suicide missions to keep the AI busy... just assign  your production planet to a control group and que them to the  battle, and as soon as you see the supply become available que more ships.. so yeah it does require a minor level of micromanagement, and also i'm assuming you have multi-factory setups for fleet building and that you've researched atleast some of the production boosters in the civ tree. For defense, another thing you can do is send in a bunch of colony frigs to keep retaking the bombed world to keep the AI busy. 

As for the invasion part, it is true that a TEC fleet isn't good enough to stand toe to toe with max combined fleet of the other races,  but your ability to have continuous reinforcements is the saving grace. Expect to lose a lot of your ships on the initial beachhead, and stay the course. Also, don't forget armor upgrades , spend more resources on that rather then the shield ones, and if you cannot micro the Kodiacs afterburner try switching to a faster unit for the initial assault.. LRMs maybe? Also, try and research quickjump calculations as soon as you have access, and try your luck with the artifacts.  Again, make sure that your build que is always active if you have any supply to spare, assign production to a control group and rally to fleet, and unfortunately you do need to micro your cap ship abilites a lot more as TEC, as most of them are target rather than AoE

I my self am a Vasari player and can say I had just as much difficulty playing by my self against 3 unfair AI as I did with TEC, just different types of difficulties.

Well, I am currently playing gateway as a TEC vs. three hard AI's in locked teams, I almost immediately maxed my fleet capacity and rushed the gateway planet, and took it.

Colonized with the capitol ship, expanded fleet capacity, designated homeworld, moved in to the Xi system and started colonizing.

Now I've got a rather nice simple defense set-up, and 14 capitol ships in my main fleet. Half of which are Marza's...

I am PUMMELING the AI, decimating worlds as I go along, and every planet in the XI system has a superweapon set to auto-fire.

I went less heavy on the carriers than I usually do, as I could no longer justify the hideous cost in supply. 14 supply for a squadron?! You've got to be kidding me.

Instead I opted for more LRM's, hishoki's and kodiaks. The kodiaks die immensely fast, perhaps because they insist on charging the enemy well out of my hishoki's repair range.
I also found the odds improved greatly when I disabled the hisho's auto attack, only allowing them abilities.

Now, the only problem I have, is a severe lack of concentration points. Every world can really be accessed from a multitude of places, fortunately the gateway planet seems to link them so maybe I can move the defense fleet in on an "as needed" basis.

For now I will just enjoy myself with destroying every single planet, and keep them constantly re-colonizing as I move along, until I get enough respite to start taking worlds for myself.

I haven't maxed fleet capacity, yet, but my economy seems to be able to handle the strain pretty well. I've maxed both research trees, and things are looking rather well.

Thanks for the tips all, I'll keep you posted if I manage to finish this game before I get my new system parts in the mail, and have to install that and format my comp.