When you click to boost the Elixir Collector a clock appears for a few seconds.
It is a good idea to put your Elixir Collectors outside of your Walls, so they can act as a distraction to units such as Barbarians and Archers.
Attackers can steal up to 50% of the uncollected Elixir in the collectors. Having too many uncollected resources will make you a more attractive target.
If an Elixir Collector is destroyed in an attack while it is being upgraded, no Elixir will be lost as the collector is empty during this time.
Pay careful attention to the location of Elixir Collectors when planning your attack, as Elixir Collectors are usually only marginally protected and can be quite lucrative, especially at high levels. Many times a single Archer can be placed in such a way that it can destroy an Elixir Collector while standing clear of any defenses.
If you see a round number of Elixir in a raid, it is most likely going to be in the Elixir Collectors rather than in the Elixir Storages (example 90,000). Although round numbers can occur in Elixir Storages, they happen much more often when Elixir Storages have been emptied by a previous raid and the resultant shield has allowed the Elixir Collectors to completely fill up.
When raiding for Elixir, you can tell if the Elixir Collector is full or not by looking at the tank. In fact it is easier to tell if Elixir Collectors are full than Gold Mines, so use that fact to your advantage even when farming Gold (Elixir Collectors will fill at the same rate as same-level Gold Mines).
Elixir Collectors undergo significant visual changes at levels 5, 8 and 10.
When initially constructed, the Elixir Collector consists of a large, transparent cylindrical vat standing vertically on a wooden base. A long, narrow metal tube extends from the top of the vat and bends down to a small brass pump with shutoff valve embedded in the ground. Elixir periodically bubbles out of the air vent on the top of the vat.
At level 2, a second narrow metal tube appears, and the brass pump grows larger. Additional tubes are added at levels 3 and 4, with the pump also increasing in size.
At level 5, the four narrow metal tubes are replaced with one much larger diameter tube, and the brass pump and shutoff valve moves to the opposite side of the collector. The shutoff valves' wheel grows much larger, too. A flat metal skirt appears around the base of the collector as well.
At level 6, a second, smaller metal tube appears, connecting to a smaller (valveless) pump on the opposite side of the collector. The level 7 Elixir Collector adds another smaller tube.
At level 8, the two smaller tubes on the left side of the collector are replaced with a single large-diameter tube, which joins the original tube at the top of the collector. The second pump on the left side of the collector receives a small shutoff valve wheel as well.
At level 9, the wooden cap on the cylindrical vat is replaced with brass. The collector gets a third large tube coming from the back and a brass reinforcing bar appears on the front of the vat.
At level 10, the top of the collector receives a large brass junction where all the tubing enters. Two additional large-diameter tubes are added as well, for a total of five. Shutoff valves are visible on three of the tubes as well as on the top of the junction. Additional reinforcing bars appear on the front of the vat.
At level 11, the shutoff valve on the top of the vat disappears, replaced by still more tubing. The reinforcing bars are replaced with wide brass reinforcing plates that nearly cover the entire vat.
At level 12, the tubes on the sides and back become larger, and spikes are added to the top. The small pipe in front of the collecter is moved to the back. On the top, there are now three tubes instead of two, and more bolts are added to the top and the front.
It takes 15 days, 21 hours, 20 minutes and 10 seconds to fully upgrade the Elixir Collector.
A downside with Elixir Collectors is that even though the cost to upgrade them is low, the time it takes to complete them is relatively long.
Although every other number matches between the Gold Mine and Elixir Collector, the level 5 upgrade prices are different (3,000 Elixir for the Gold Mine, 3,500 Gold for the Elixir Collector).
The Elixir Collector is one of the 8 buildings that you are automatically set with at the beginning of the game.
There is a new Elixir Collector available at every Town Hall level with the exception of levels 7, 8 and 9.
* The Catch-Up Point is the time at which the newly upgraded Elixir Collector has equaled the total production of the collector had it not been upgraded - this does not consider recovering the cost of the Gold required to perform the upgrade.
Caveat: The Catch-Up Point calculation assumes that the player collects all resources from the Elixir Collector without allowing it to reach its storage capacity, as resource production ceases at that point. This is more of a concern at lower levels where the capacity is limited and Time to Fill is relatively short. If the player is unable to regularly collect and achieve the full potential of the collector, the Catch-Up Point is actually shorter and performing the upgrade becomes more advantageous.