Some time ago I did some tests on mana on defense as well and found slightly different numbers.
There are a few threads where players investigated the mana generation for the defense, which I took as a starting point for my own investigation.
First was thread with a statement from @Petri that @Aquaginera_7DD cited:
“Mana needed for each mana speed is not the same for offensive and defensive heroes in raids”:
In that thread she also reported on her findings:
it takes a fast hero without mana troop 10 turns to be fully charged without getting hit
it takes a slow hero without mana troop 15 turns to be fully charged without getting hit
it takes a fast hero with +7% mana troop 9 turns to be fully charged without getting hit
I tested these situations and could confirm them.
@Damirius did some further analysis by counting the pixel length of mana bars:
Current theory is:
combo 1 tile (1c1) is 66.66% of a tile in offense, and End of Turn (EOT) bonus is 1.30 of a 1c1. This gives (without any mana bonus):
Mana Speed Predicted 1c1 Predicted EOT Measured 1c1 Measured EOT Very Fast 10.256% 13.333% - 13.42% Fast 8.33% 10.83% 8.2% 10.5% Average 6.666% 8.666% 6.5% 8.5% Slow 5.555% 7.222% - - Very Slow 4.938% 6.420 - - Mana gained from hits depends on current number of combo. Combo 2 hit gives 90% of Combo 1 hit, and Combo 3 hit gives 90% of Combo 2 hit, and so on.
I wanted to do some tests as well, but I quickly gave up on the pixels and instead looked at the number of turns it takes to charge a hero on defense. To get more data I then applied mana generation debuffs.
Results are here:
How many turns are required to charge heroes on the defense?
turns (not charged yet) turns (charged) ninja charge 1 5,71 5,72 magic 1 6,23? 6,24? styx 1 6,97 6,98 very fast 7,58 7,59 fast 9,07 9,08 average 11,52 11,53 slayer 12,4 12,45? slow 14 14,01 very slow 15,26 15,27 How does this compare to the tiles for the attack team?
tiles on attack turns on defense ratio Charge 1 4,89 5,72 1,1698 Magic 1 5,5 6,24? 1,1346 Styx 1 6 6,98 1,1634 very fast 6,5 7,59 1,1677 fast 8 9,08 1,135 average 10 11,53 1,153 slayer 11 12,45 1,1319 slow 12 14,01 1,1675 very slow 13,5 15,27 1,1312 Which mana generation bonuses are then required for the defense to charge in X turns?
Charge 1 Magic 1 Styx 1 Very fast fast average slayer slow very slow turns 5,72 6,24 6,98 7,59 9,08 11,53 12,45 14,01 15,27 3 91% 108% 133% 153% 203% 285% 315% 367% 409% 4 43% 56% 75% 90% 127% 189% 212% 251% 282% 5 15% 25% 40% 52% 82% 131% 149% 181% 206% 6 -5% 4% 17% 27% 52% 93% 108% 134% 155% 7 -19% -11% -1% 9% 30% 65% 78% 101% 119% 8 -29% -22% -13% -6% 14% 45% 56% 76% 91% 9 -37% -31% -23% -16% 1% 29% 39% 56% 70% 10 -43% -38% -31% -25% -10% 16% 25% 41% 53% 11 -48% -44% -37% -31% -18% 5% 14% 28% 39% 12 -53% -48% -42% -37% -25% -4% 4% 17% 28% 13 -56% -52% -47% -42% -31% -12% -5% 8% 18% 14 -60% -56% -51% -46% -36% -18% -12% 1% 10% 15 -62% -59% -54% -50% -40% -24% -17% -7% 2% 16 -65% -61% -57% -53% -44% -28% -23% -13% -5% 17 -67% -64% -59% -56% -47% -33% -27% -18% -11% 18 -69% -66% -62% -58% -50% -36% -31% -23% -16% 20 -72% -69% -66% -63% -55% -43% -38% -30% -24%
My impression on combo 1 tiles is that they give at least 2/3 of a turn of mana for the defense - it looks like it is a bit more than that, but my data there is not as clear as I want it to be. With 2/3 of a turn you are on the safe side and it easier to calculate:
without mana generation buffs/debuffs 3 combo1 tiles that hit a target let the target charge in 2 turns less.
Data:
I found that fast heroes on defense with 0% mana generation charge with
- 0 combo1 tiles and 10 turns
- 1 combo1 tiles and 9 turns
- 2 combo1 tiles and 8 turns
- 3 combo1 tiles and 8 turns (tile < 0.69333 turns)
- 4 combo1 tiles and 7 turns
- 5 combo1 tiles and 6 turns
- 6 combo1 tiles and 5 turns (tile > 0.68 turns)
- 7 combo1 tiles and 5 turns
- 8 combo1 tiles and 4 turns
- 9 combo1 tiles and 3 turns
and average heroes with 0% mana generation charge with
- 0 combo1 tiles and 12 turns
- 1 combo1 tiles and 11 turns
- 2 combo1 tiles and 10 turns
- 3 combo1 tiles and 10 turns
- 4 combo1 tiles and 9 turns
- 5 combo1 tiles and 8 turns
- 6 combo1 tiles and 8 turns
- 7 combo1 tiles and probably 7 turns (didn’t get that situation)
- 8 combo1 tiles and 6 turns (tile > 0.69125 turns)
- 9 combo1 tiles and probably 6 turns (didn’t get that situation)
- 10 combo1 tiles and 5 turns
So far so good, but I also got a fast hero with 7% mana generation that charged with
- 5 tiles in 5 turns (tile > 0.697196)
or a ninja with 0% mana generation that charged with - 1 tile and 5 turns (tile > 0.72)
which doesn’t match with the < 0.693333… probably some mistake on my side.
=> if somebody could check these situations and find my mistake that would be great 
