Look, we all love shields, they are very nice and useful.. but please.. stop spamming batteries as your HULL. It mentally hurts me.
So, why is there such a thing as too many batteries? One phase: Roditic Chemical Explosion [RCE]. (A word play on Thermal Nuclear Explosion, see the top right picture in this section).
Batteries are sensitive equipment. If a big HE bullet finds an ion pulse cell in front of it, that pulse cell is gonna go ka-boom, quite impressively too. But I hear you ask. "But how will a bullet hit a battery behind shields?" Well, what if those shields became offline? Or if the tech was inside your main shield and you did not have a small internal shield? My point is, batteries are not something to spam willy-nilly, they are dangerous. I have seen many community techs both within the game's enemy pool and on the workshop which have so many batteries, a single volley of 2 HE Mk3 battleship cannon shots causes it to light up brighter than a 4th of July fireworks display in New York if the repair bubbles don't stop the RCE. Not much to salvage either after the fireworks...

Explosions from both battery and explosive explosions (without the Explosion Nerf unofficial mod from TT Mod Manager) operate without notable damage dampening from battery to battery, meaning that no matter how far away from the explosion's center a block is, it will sustain similar amounts of damage as if it was right next to the explosion, (although, armor and certain hull blocks increase damage dampening in my experience but the lack of fundamental damage falloff from being far from an explosion's center is just a stupid balance decision too many games make). So if an explosive shot hits your hull, it does say... 1,500 damage at its center. 4 layers of basic blocks inside the tech latter, a block at the edge of the explosion radius sustains probably 1,100 damage (and probably 500 if armor blocks where in the way, again, based on only live experience). This is why a chain reaction of batteries is a very violent reaction. Low battery health and large explosion radius on death. Won't take long to decimate or vaporize your entire tech unless the repair bubbles stop the RCE by stopping batteries damaged by the RCE from exploding and continuing the chain of explosions.

Battery spam has a major flaw, kinetic hell fire. Kinetic weapons have bonus damage to EPs in batteries, they don't bypass shields in any way but shear quantity and quality shreds battery EPs. If you face an enemy which has enough anti-shield weapons, no amount of batteries will save you, and once shields are down... KA-BOOOOOM!!
Best of all for kinetic weapons, they are mainly shut down by armor, which is not commonly used. Even with armor however, your battery spam is vulnerable to AOE damage (unless you use the Explosion Nerf mod) and if breached by AOE damage an RCE will be imminent and no amount of armor will save you from the chain reaction.

This is based on the idea that the techs fighting here have no more than a 3M BB difference. A battery spam tech that costs 5M would always win against a kinetic heavy tech that only cost 2M. Exact numbers about this are only theorized. The BB difference may be larger or greater.

----- 0. Don't battery spam. Please don't. Just add hull and armor, not only more batteries!

1. Instead of making massive battery spines/cores, place battery sections isolated from other batteries, so when a battery section is compromised, it does not take anything else with it.
   
   
2. Keep batteries away from vital parts like rotors and cabs.
   
   
3. Use armored hull like the HE six block instead. That block is a very good block for making study hulls to separate batteries safely. (Explosion dampening exploitation).
   
   
4. Use GC blocks to space batteries apart by shear distance. A system I do is separating GC battery packs between two GC blocks. This does not apply to battery cores. (Many batteries in a single, safe area deep in the tech).
   
   
5. Place armor around batteries which are following #2 to increase explosion dampening from enemy shots to ensure the batteries don't sustain significant damage and can be healed quickly.
   
   
6. Have fast repair bubbles (preferably Venture) constantly heal batteries vulnerable to damage. When a battery goes critical and blinks red, it can still be saved by a repair bubble. Just don't rely on this for when all EPs are diminished.
   
   
7. Use the Gluon Mega Battery, just be weary that this battery is quite frail and can implode prematurely, taking all the stored power it has with it. See my Gluon Mega Battery guide for more information.

The description of slopes "deflecting" and absorbing shots is not a lie (though deflecting yes, but that just means they take less damage, not physically deflecting) a slope experiences less direct damage than hull, sloped armor is especially apparent. Slopes also heavily increase explosion dampening, more than armor plates in fact! Armor is just good when an area is flat and needs added protection, slopes are the ideal hull armor. The only time you can have too many slops is when they are beginning to become your hull, are hogging connection space for weapons, or are vulnerable to structural collapse due to the lack of attach points on slopes. Always use slopes in free space, it looks good and is practical.

=Solution: Self explanatory.=
In this case, this tech is literally made of slopes, has connection issues causing a quarter to be severed off upon the loss of a single block, but this is not lethal to the tech in such a situation. "The weapons where already gone on that side, was just dead mass."

Repair bubbles cooperate when stacked, having two repair bubbles healing one block does double the amount of HP restored at their combined EP usage independently. Shields do not benefit from stacking what so ever, only layering (having a small shield inside a large shield, but even that is unnecessary for most techs). The only instance which this can be an exception is when shields are spaced too far apart, but there are many conditions that dignify if this is of any concern. The space creating the indent in the shield's crossing can be insignificant, so if an explosive shot lands inside that indent, it does not do significant damage, or it is out-right a one-in-a-million type of shot, yes if a shot gets inside the indent it can do large damage (assuming its explosive) but that type of shot is so unlikely, you would be better off not shielding the indent, saving lots of EPs. Having a ton of shields to effectively make a brick wall is SO ENERGY INEFFICIENT (damn you auto correct). It hurts me mentally to see so much energy be used for such little purpose.

Also, a massive stack of shields does not look good. Its very highlighting and obscures the visuals behind/inside it.

1. Don't... Spam... Shields... Please.
   
   
2. Space shields neatly, creating indents you find acceptable.
   
   
3. Place more efficient shields inside indents, preferably venture shields, this helps when you have two main shields far apart but the indent is still somewhat unlikely to have a shot hit inside but not unlikely enough to remain an unshielded area, having more efficient shields fill in the indent is very energy efficient. Just don't place too many.

NOTE: It may be wise to place a small shield inside a large shield in the event an enemy tech breaches inside the large shield. Bullets originated from inside the shield are not absorbed, only the surface of the shield blocks incoming shots. A venture shield bubble next to a HE Havoc shield would do very nicely for this situation.

---

Note: Since I have retired from Terra Tech I doubt I will be able to update this section to the new D-Shields energy drain balance.
=====
Short answer: Don't use them unless it is for aesthetics.

They have the same efficiency as their bubble counter part or are so insignificantly more efficient they might as well be the same efficiency.

Worst of all, the surface area of the D-Shield is SO INCREDIBLY SMALL COMPARED TO BUBBLE SHIELDS you need to place more D-Shields to actually protect the area a single bubble shield does and the total energy drain from the extra needed D-Shields use likely over 3 times the energy as what a single bubble shield of its type could of achieved.

How much more surface area does a bubble shield project than a D-Shield of the same size?
3.14159 or PIE, TIMES MORE.
You will need 3 D-Shields to cover just a bit less surface area than a single bubble shield. This is based on a perfectly square D-Shield and a spherical bubble shield with length=radius which is not remotely true in for TT D-Shields and their bubble counterparts. Only the BF rectangle Directional Shield has a larger length than the radius of a Venture Shield Bubble This means that using any D-Shield, you will need well over 5 of them to cover the same surface area of a single bubble shield from the same faction.

If you want to see my entire analysis of everything about the Directional Shields, visit the link below. The forum post also goes into what a Directional Shield is as a defensive system. Both comparing to other types of shields and the unique properties of a 2D shield.
https://forum.terratechgame.com/index.php?threads/directional-shield-balancing-advice-justification-and-visualization.21903/

Armor... is... not.. USELESS! ;-;
In the event a hoard of kinetic weapons shred your shields, armor is a counter to kinetic weapons, standing strong under hail fire. Armor as said before also causes explosion dampening, causing the almighty explosion based weapons to be a bit more bearable when the shield counter measures go down. In the event your tech looses power, that should not outright spell out the end. If it does.. In my opinion, you built bad (no offense) unless it was "intended" or the tech depends on Anti-Gravity.

The counter to armor is lasers, they cut through it like a laser. The issue to this are.. lasers have the worst bullet velocity I have ever seen and I may bet an Olympic runner can out run the stupid projectile 5x over, are not lasers, and need target prediction to be useful outside of melee range. Even Mt. Everest can dodge the lasers found in TT.
Unless you are playing with mods to fix this, you should never think "laser" weapons exist in TT. (Except disk lasers of coarse which are indeed lasers). With the counter to armor not being practical (unless mods save the day), armor is mostly unopposed. Generally, armor is a good way to ensure a tech lives after shields go down. Unless you do mistake #0, then you are for-doomed before loosing energy anyways. Then you have the details of mistake #1 describing armored slopes a bit. Armored slopes like the HE wrap armor can be a real game changer when shields are down and you did not do mistake #0.

Place armor at every last spare connection point that won't cause mechanical problems.
In this case, a harvester tech has an excuse to not have armor though since it is not meant for combat, it does not apply to Tanky 101 which includes this entire guide. My point still stands though.

I said it before, I will say it again. HE six block is the best hull block out there. Use it like a mad tech!... *Ahem*. Back to the actual mistake.
Venture lads, this mistake does not apply to you.... Wait.. Why would you be here anyways?

The worst feeling is when you are in a fight, doing decent then all the sudden half your tech just collapses onto the floor because your last hull connection was compromised. Very good for salvage rights, very bad for ensuing your future vacations remained scheduled. This also applies to batteries being used to create tech spines as said in mistake #0.

When making hull, it is best to use long blocks that have large surface area compared to volume. Most GC blocks have lots of volume and little surface area, making the blocks a big target and easy to focus down and plop off. We want to prevent that as much as possible here. Now.. NEVER... USE.. ONE BLOCKS! (Unless you are building bite-sized). They have maximum surface area compared to volume along with their small independent health. AOE damage types delete block spam and gain more value from doing so as for every block damaged in the explosive radius, the more efficient the single shot was and the more total damage it deals. Its partly why explosives are very powerful in TT as block spam is literally what techs are made of. A bundle of many many many separate blocks slapped together like a Lego set.
We want the block making up your tech to survive damage as much as possible when being tanky. Multiple GSO 5 blocks are much better for this than a few GC blocks when strategically placed to have only the 1x1 side of the block exposed at the surface and the 5 blocks behind it inside your tech. This is very hard to actually do in practice and possibly even practically impossible functionally except on mobile fortresses and airships, but in the ideal, it may be better than the HE 6 block (unless orientated to also exploit this and you manage to solve the structuring puzzle so the 6x2 face of the block is not the exposed side).

There is the exception of using GC blocks for interior hull which are not planned to be shot at constantly and any breaches in the armor shell leave increasing chances of the internal block being shot at, not guaranteed chances unless the surrounding area is stripped, which is a very acceptable scenario. HE 6 blocks are heavy after all and very expensive for just basic blocks.
Also in mention of GC blocks: Due to their volume basically giving them 4x the health for being 4x the size of a GSO 1 block, they make for a very neat sturdy and light-weight hull for large techs much better than any GSO block. GC blocks also have the same density as GSO blocks which is 1kg/m^3, BF and Ven being lower but far more frail. GSO is very much "the middle ground" in every way. It is even made better that their large size means less independent blocks can be in a single area so less total blocks are damaged by an AOE explosion which gain massive value from damaging multiple independent blocks at once.

1. Use HE four and six blocks when making internal hull.
   
   
2. Use GSO 5-3 blocks for thin internal spine hull.
   
   
3. Avoid using GC blocks for exterior hull, use them for internal hull to occupy large spaces but be sure to surround them with blocks much more suited for taking damage head on!
   
   
4. Reinforce the hull. (#5 and 6)
   
   
5. Add more connections connecting the tech together.
   
   
6. Add armor to the hull.
   
   
7. Incorporate slopes, they take reduced damage, enabling repair bubbles to heal them easier and such, last much longer for less energy. Slopes also stand strong under kinetic and explosive fire. Beware of lasers if you have target prediction mods.
   
   
8. Honestly, just spam HE six blocks within the tech to create branches and spines connecting the tech together. The blocks are very sturdy and likely to out-live the surrounding, non-HE blocks.
   
   
9. Avoid using GC blocks in general. Although this can cause issues regarding to mass, GC blocks are merely XL GSO blocks, both corporations have the same density regarding their blocks. The large HP pool of GC blocks is mearly due to their size, imagen combining the HPs of four GSO one blocks into a single block, that is GC blocks in a nutshell for the most part.

Additionally, if you are building a very large tech that has a lot of volume, I recommend using BF scaffold blocks every now and again for internal hull, GC blocks for large and unimportant internal areas, and/or some GSO blocks in areas unlikely to experience sustained exposure to damage.
Spamming hundreds of HE blocks adds significant mass and cost, when standard blocks of standard mass and durability are dirt cheap. The scaffolding blocks are lighter than GSO/GC and are still sturdy due to large surface area vs volume as mentioned before. The cost may still be a problem though in large numbers.
The main premises is how these blocks are not meant to experience direct fire under normal situations, so the HE blocks act as an outer or layered shell that don't make the entire structure of your tech (a mistake I have made with my larger techs and have since became mindful of). I advice you to still add some internal HE blocks for reinforcement depending on the size of your tech in the event the outer shell(s) are peeled off.

Long blocks of any type are much harder to dislodge independently then any other shape of a single block due to large surface area vs low volume as previously mentioned. Although a 5 block from BF and GSO is not as large as a HE six block (by a single cube), it is still better than a mass of venture blocks occupying the same volume anywhere or a GC that can be focused down or any 1 block of any type, any where.

If you play From The Depths, you may know well how the orientation of your 4 blocks can make the external armor far more sturdy and how they also are outright more sturdy than their smaller variants by default (partially to encourage their use and discourage the spamming of 1 blocks). In fact, life actually knows this principle too with some (my knowledge here is limited so it may be already standard in evolution's engineering) living things creating organic structures using this principle to increase structural durability and integrity... Though you don't want to actually see it because it is always inside the living thing and the structure concept itself can be very disturbing to visually see due to so many independent lines being visible in a small space.
Just imagine a roll of spaghetti neatly bound together and face towards one of its end so the length of the spaghetti is not visible. Each line of pasta covers very little independent surface area (even when placed length wised) and that small surface area is supported by the full hidden length behind it.

I don't need to say much, but I am gonna anyways.
Honestly, why would you ever not use the HE cab? Weight? Cost? Connection points? Size?? I'm unsure...
Anyways..

Having one cab is just BEGGING to have your tech collapse prematurely from a sudden burst of AOE damage. Unless you got a HE havoc shield protecting your cab, if an explosive volley comes in and is large enough, the splash damage even with explosion dampening can insta-kill your cab, and pop goes your entire tech. It is a very sad sight to witness.

• Create cab zones. (Areas built around the cab that contain things like gauges, radar, AI modals, and mainly: surrounding armor and or extra repair bubbles to protect the cab).
  
  
• Have more cabs. I did not agree with the single cab requirement for the TT Naval Warfare Challenge.
  
  
• Use HE cabs 24-7. (24-7 is not a necessity but I can't think of reasons why not to use only the HE cabs when the only thing cabs are good for is existing).
  
  
• Space your multiple cabs away from each other, most weapons lock onto the cab so having cabs nearby other cabs does nothing but allows the same hole that was created to kill the first cab to be used to kill other other cabs rather than needing to make a new hole. Exception applies to using large single blocks like the HE battleship cannon or GC blocks where a single block can be destroyed to expose multiple cabs due to the large area it was occupying and how limited space was for placing cabs in various areas.
  
  
• Have your cabs be in safe zones. Ex: Deep inside the tech surrounded by HE 6 blocks with Ven repair bubbles in case AOE damage somehow gets to the cab and only needs some minor repairs.
  
  
• (For single cab requirements like in tournaments:) Bury your cab as deep in your tech's hull as possible where within reason, from all sides of the cab is the most amount of blocks between the cab and the outside world while being less mandatory for the up and down direction as only planes and airships can hit from above and only things that fly can be hit from below in which is when you don't want to place the cab near the bottom of the tech (except when considering the RR 0G cannon: A weapon so spicy, I would sue RR for calling it a funny floaty floaty prank. I renown it as an Anti-Tank weapon and if manual targeting was a thing, I wouldn't say it doesn't work on very large ground techs).
  Force the enemy to need to chew through half your entire tech just to reach the main cab!

Having 6 cruise missiles all lined up is very nice and satisfying... adding another 15 is also rather satisfying.. until a single bullet comes and ka-boom! Happy fourth of July! (Even more so than in an RCE!) This applies to all explosive weapons that have a proper explosion upon detonation. An example that does not apply here is the rail gun, it does indeed explode, but the explosion is more of a poof than a KA! BOOOOOOOOOOM!.
Instead of making an ordnance of exterminatus, move each of those weapons to various parts of the tech. Unless you have a size restriction, play around the locations. Explosion dampening is your friend in small volumes! Now, this mistake is a bit more.. leeway, much to how it is #6. You can make extermination protocol setups that have the "effect of this mistake", needless to say, this may be more of a calculated risk than a mistake! A glass cannon type of situation. "The enemy can't hurt me if I delete it from existence."

• Space explosive weapons throughout the tech, none next to each other unless they are in an area that will be fine going ka-boom or "combining" weapons together, like 2 Cruise Missiles next to each other being mentally considered one weapon (just don't do that for over 3 of em).
  
  
• Use less big boom weapons like Warhammer missiles er.. wait was it Seeker? What ever. ...over a Cruise Missile launching platform that is more missile than platform.
  
  
• Armor up the weapons without blocking their line of fire. (Personally recommend this one! You can also get creative for missiles that won't rotate like AA Seeker Missile pods or Ballistic Missile silos).
  
  
• Strategically place volatile weapons in locations unlikely to be shot at, IE: on a weapon rack above your tech or at the rear where cruise missiles launch up and fly above your tech.

"Why add armor when you can add more guns? Let the shields protect the frail hull!"
That is until a HE MK3 Battleship shell slams into your shields, stripping you of most small weapons in the affected area. (The HE MK3 BS Cannon has the largest explosion around, making it proficient in stripping frail weapons, especially VEN Hail Fire Rifles.)

Its understandable we might ask ourselves the question stated above and go with more guns. Kill the enemy before it does damage to you is a valid tanky tactic. The Tanky Combat 101 series however assumes its a fair match to the death, not casually unleashing Armageddon on the local techs and never encountering a significant foe. So with this in mind, the ability to kill the enemy before it deals significant damage is less and less viable as a tanky strategy as you sacrifice proper resilience for more firepower. Instead, there is a middle ground... Use large weapons as much as you can! Large weapons are very hard to knock off compared to small weapons, mainly due to inflated HPs from being a larger size or good-old HE gives you an armored turret. Large weapons can provide significant DPS for little space, take the Megaton cannon for instance, it is MUCH more lethal than 8 3-pound cannons (mainly due to bullet velocity, AOE, and reliance on target prediction), so instead of adding 8 3-pound cannons, add a single Megaton cannon, this leaves 4 connections to add some armor! A large armor plate to be exact! Making this form of habit is very helpful, gives you an idea on when to add weapons vs armor, large weapons can be added towards the back of a section, having a clear firing visual and adding plating in front of the weapon, not hindering the firing vision what-so-ever, unless you are using war-hammer missiles and or wanting the weapon to have a good firing arch towards the ground, then it can get a bit awkward.

Solutions:
1) Use a few large weapons vs many small weapons.
2) Place large weapons strategically to add more armor around the tech.
3) Use small weapons as "point defense", accommodating small areas where large weapons can't fit and/or have a good firing line and armor would be odd in that location. On corners especially!

Here is an example of what I am conveying, instead of adding mass weapons, the tech has a primary large weapon, filling the rest of the connections with armor and movement parts, having some small guns in peculiar places armor would not fit well in and or wouldn't be entirely practical.

This concludes the current list, I might add more in the future but these are the top 7 mistakes I see in many tech designs. Obviously there are more but the top 3 are classed as "mentally painful" in my book.
Now remember, this is an edition of the Tanky Combat series. Its all about surviving an onslaught and fighting successfully. In the case of a transport tech for example, it may be necessary to "posses" some of these "mistakes" to for-fill its functions.

This guide is up-to-date for TerraTech version 1.4.15 and will be prioritized for updating to any version that adds something special. Like more shield piercing weaponry.

Skin mods used:

• All CrossCorp skins by Payload Studios.
  
• DarkLight Skins by kevinlakecity5