diff --git a/api.lua b/api.lua
index 043bfb2..9056cdf 100644
--- a/api.lua
+++ b/api.lua
@@ -18,6 +18,12 @@ local S=minetest.get_translator("industrialtest")
 
 industrialtest.api={}
 
+-- \brief Adds power storage to metadata
+-- \param capacity How much EU item/node can store
+-- \param flow How much EU can flow in or out item/node per industrialtest.updateDelay
+-- \param ioConfig Input/Output configuration in following side order: -X, +X, -Y, +Y, -Z, +Z
+--				   a - bidirectional, i - input, o - output
+-- \returns nil
 industrialtest.api.addPowerStorage=function(meta,capacity,flow,ioConfig)
 	meta:set_int("industrialtest.powerCapacity",capacity)
 	meta:set_int("industrialtest.powerFlow",flow)