How do shields work in combat?

Can anyone explain to me how shields work in combat? Is the shielding from each of your ships/defenses cumulative? Why are shields for an attacker so much higher than for a defender?

So in order to damage a ship or structure, you first must destroy the shield. After every round (max 6 per fight), the shields regenerate to their full strength. This is the main reason you want few rounds (as the attacker), as you have to pierce the shields every round.

Let's look at an example:
10 BS (1.700 attack, 340 shield, 10.200 armor) with 7, 7, 7 research
VS
1 SS (1.5 attack, 3.000 shield, 3.000 armor)
1 GC (1.650 attack, 300 shield, 5.250 armor)
5 RL (120 attack, 30 shield, 300 armor)
2 HL (375 attack, 150 shield, 1.200 armor)
1 IC (225 attack, 750 shield, 1.200 armor) with 5, 5, 5 research.

For the sake of argument, the first round has one BS against a single structure.
SS vs BS = no damage, 1.700 attack cannot overcome the 3.000 shield, and the 1.5 counter-attack cannot overcome the 340 shield.
GC vs BS = damage, 1.700 attack overcomes the the 300 shield, dealing 1.400 damage to the armor of the GC. 1.650 attack overcomes the 340 shield, dealing 1.310 damage to the BS armor.
RL vs BS = destroyed RL, 1.700 attack overcomes the 30 shield, dealing 1.670 damage to armor, destroying it. RL attacks with 120
which does not overcome the 340 shield, BS unharmed.
HL vs BS = destroyed HL, 1.700 attack overcomes 150 shield, dealing 1.550 damage to armor, destroying the HL. 375 counter-attack overcomes the 340 shield and deals 35 damage to the armor.
IC vs BS = damage, 1.700 attack overcomes the 750 shield, dealing 950 damage to the armor. 225 counter-attack does not overcome the 340 shield, BS unharmed.

Round 1 results:
5x RL destroyed and 2x HL destroyed
Remaining:
7 BS full strength (vs RL, IC, SS)
1 BS with 8.890 armor left (vs GC)
2 BS with 10.165 armor left (vs HL)
1 GC with 3.850 armor left
1 IC with 250 armor left
1 SS full strength

This continues to the next round where the IC will be destroyed. Damage is cumulative for a single round, so once the shields are down, they remain down. It will take 3 BS hits in a single round to take out the GC. It will take 4 BS hits in a single round to take out the SS.

A note, once a ship reaches 30% armor remaining, there is a chance it will self-destruct.

I usually find that defenders have the higher shields. I attacked a guy yesterday that I attack often. With 13 BC and lvl 10 weapons tech, I could not defeat his only defense, a large shield dome. I drew twice before I gave in and sent tons of destroyers. The combat sim showed my BC winning, not the shield.

A note, if the attack power if the ship is less than 1% of the defending shield, the attack is voided. This is called deflection or the bounce effect. Notably, this means no amount of light fighters can destroy a large shield dome. In a similar manner, fighters (light and heavy) cannot hurt a deathstar. A cruiser can only if the cruiser's weapons tech is many levels higher than the deathstar's shield tech.

Well, the guy who attacked me had a large fleet, but his shields were greater than 10x my defense shields according to the battle report. (I wish I had remembered to post the battle report, but alas its gone now.) Maybe it's just because he had such a large fleet..... 475 BS, 50 BC, 45 Bombers, and 40 Destroyers vs my 600 RL, 350 LL, 100 HL, 25 GC, 100 IC, 1 SS, 1 LS, 10 BC, 10 BS, and a few other small ships.

honestly, not much u can do about that force, but have loads & loads of defense & hi combat tech. Thats about the size of the force that hit me & i had about 15 turrets & a load of battle vessels & got wiped out

A simple comparison shows that he has far more shields. Let's assume you both have no shield research:

475 BS (200 hp x 475 ships = 95.000)
50 BC (400 hp x 50 ships = 20.000)
45 Bombers (500 hp x 45 ships = 22.500)
40 Destroyers (500 hp x 40 ships = 20.000)
Enemy total: 95.000+20.000+22.500+20.000 = 157.500 shields

600 RL (20 hp x 600 launchers = 12.000)
350 LL (25 hp x 350 turrets = 8.750)
100 HL (100 hp x 100 turrets = 10.000)
25 GC (200 hp x 25 cannons = 5.000)
100 IC (500 hp x 100 cannons = 50.000)
1 SS (2.000)
1 LS (10.000)
10 BC (400 hp x 10 ships = 4.000)
10 BS (200 hp x 10 ships = 2.000)
Your total: 12.000+8.750+10.000+5.000+50.000+2.000+10.000+4.000+2.000 = 103.750

Now add 10% for each level of shield research. He gains 157.500*.1 = 15.750 for each level while you only gain 103.750*.1 = 10.375. So if he had lvl 10 shields, then he has about 104.000 more shields than you at lvl 10. But if you only have lvl 7, he then has about 134.000 more shields than you. He likely was a level or two higher than you, so he should have lots of shield.

I'd say the problem was not so much the shields, but the firepower. The bombers and destroyers had rapid fire against most of your structures. Also, as pointed out in my above post, none of your RL, LL, HL would take more than one hit. Check out the numbers too. He had 610 ships, you had 1097 ships/structures. It takes about 7 RL to break a destroyer's shields. So you would have needed to out number him by about 4:1 to hold him off. Especially as your great numbers come from RL and LL, both of which can only take one hit and have rapid fire from the bombers and destroyers. I'm not at all surprised he beat you.

Shields do play an important role in battles. However, most ships/structures have rather low shields compared to their firepower.

Here is the ratios of firepower to shields:
RL 4x
LL 4x
HL 2.5x
GC 5.5x
IC .3x
PT 10x
LF 5x
HF 6x
CR 8x
BS 5x
BC 1.6x
BO 2x
DE 4x
DS 4x

Clearly there is far more firepower out there than shields.

my god, u have a heck of alot of knowledge about this game, i wish i had 1/10 of that knowledge

All of that was really helpful. Thanks tacticus

lol yes it was helpful. I don't have a problem with how badly he hit me lol. I was just wondering how he was showing in excess of 1.400.000 shield absorption as compared to my 220.000ish shields. I didn't take out but like 3 of his ships total lol.

To have attained that much shield absorption, on a fleet around that size, there would of had to been lots of bounce effect. Based on the data, there shouldn't have been that much bounce (should be none).

Then again, it is almost impossible for you to deal that much damage to begin with. Defenses only fire once per round. At lvl 10 weapons tech, your defensive structures would only deal 301.004 damage. That leaves 1.100.000 damage to be dealt by your 10 BS (also only get one shot [20.000 damage total]) and your 10 BC (has rapid fire against BS, of which most of his fleet was). But the likelihood that your BC did that much damage, considering you only destroyed a few ships, is unlikely.

If you are referring to the sum of the shield absorption, then at lvl 10 shields, he would of had 315.000 shields per round. At 4 rounds, that is a total of 1.260.000 shields and at 5 rounds, 1.575.000 shields. Your shield total would decrease greatly after the first round, so a sum of 220.000 is entirely reasonable.

Maybe I'd be better at this game if I actually paid attention to this stuff and strategized. Then again, I'm not that into it