I picked up a soul trap some time ago and it works okey. But if I'm trying to knock off a mountain lion or -- heaven forbid --a bear it takes a lot longer than 20 seconds so the spell has worn off. I've visited any number of mages guilds but no one seems to have a soul trap for sale. Is that because I already have one?

A second question: even when one of my soul gems is open (or my Azura's start) I can occasionally zap a rat but do not get the soul. Why is that? I got him fast, the gem is open, but no soul. And yet the next one I zap I'll get it! Not very consistent.

1) For stronger soul trap spells, if you have access to the Arcane University, make your own. Otherwise, go see Agata in Leyawiin Mages Guild during regular merchant's hours.

2) Not sure what may be 'causing that one. Each time you zap a rat, they were within reach of your on touch soul trap spell (purpley outline glow around the rat after casting spell?).

I usually get the enemies health really low before casting soul trap on them. This means I can usually soul trap them before the 20 secs is over.

I usually enchant a weapon with some kind of damage plus soul trap and use it that way. You need to be able to cast a spell before you can use it for enchanting, so buying that spell wasn't a waste.

Then each blow from the weapon re-applies the soul trap, and you only need it to last until the next hit (one or two seconds). Because you have the spell available to cast by hand, you can always re-start the process if your weapon runs out of charge, as it might if you get a lot of NPC enemies in a row.

If you're playing a pure mage, then there's not much use for the trapped souls, so don;t worry about missing a few. Sould gems are mainly used for recharging weapons, so this method has the weapon refill the gem (Azura's Star as soon as you can get it).