Elite: Dangerous Blog

After a bit more research I have found some of the theory behind shield recharging.

The value of 0.9 MJ/s on a 3E Power Distributor on a Cobra is the rate at which systems recharge shields. The default shield generator is a 4E with 93.58 MJ total strength. In theory therefore, a 4E shield should take 104 seconds (93.58 / 0.9) to recharge.
A class 3A Power Distributor pumps out 1.3 MJ/s, so the same shield with an A rated distributor should take 72 seconds.

Until I’ve tested this theory, I cannot be certain, but it follows that the increase in shield from the boosters would make the recharge time increase based on your power distributor’s ability to fill it back up.

Shield recharge times

Boosted shield recharge times

As you can see, if this is correct, the Cobra with 4A Shields and a 3A Power Distributor should recharge in 97 seconds. With a 0A Shield Booster, the shields are raised to 150.6MJ so will then take 116 seconds to recharge on the same ship (19% longer).

My Fer-De-Lance with 5A Shield Generator, 6A Power Distributor and four 0B Shield Boosters will therefore take four minutes and three seconds to restore shields!

My next quiz question is are shield cells based on a percentage or a fixed number of MJ? If the latter is true, then the more Boosters you use, the less effective even the best Shield Cells will become.

New in 1.2 Shield Boosters are a bit of a mystery to me at least, or were until today anyway.

They increase your shields (says so on the tin) but what does that actually mean?

Well, your shield strength is rated in Mega Jules (MJ) so, for instance if you are in a Cobra with a class 3E Shield Generator the shield is rated 61.6MJ and the best shields are a 4A, rated 125.5MJ.

You can see a full table of shield ratings here on Reddit.

What the shield booster does is multiply that figure by its “multiplier” value. If you bought a 0E Shield Booster which has a multiplier of 1.04, then your shields maximum strength would go from 125.5MJ to 130.52MJ.

What's more is they stack; if you buy more than one (two are possible in a Cobra) the multiplier values are all added. The way it does this is to calculate the increase percentage and adds that – an A rated shield booster is plus 20% (1.2) so two is plus 40%. The Cobra’s shields with two 0A Shield Boosters got from 125.5MJ to 175.7MJ!

What’s the catch? The first is power consumption. The Shield Boosters suck power like Frankenstein’s monster! The 0A Shield Booster draws 1.2MW. The second catch is recharge time. If you lose shields, the time they need to recover is much longer. How long? I haven’t been able to get a solid number yet.

Another factor for considering shield booster is cost and weight. Top end shields are expensive and heavy.

CMDR jgm on the Frontier forums has noted

I could take a 5D shield and add two 0C boosters and end up with a better shield than a straight 5A at a fraction of the cost, with lower mass and power usage.

This gets you better shields at 4% of the cost and a little over half the weight!

My 5A Fer-De-Lance shield generator has four 0B Shield Boosters, taking the shields from 478.8MJ to an eye-watering 779.16MJ!