nimbus of light + persist spell: is this right?

[Darth Stabber]

So nimbus of light acts as a light that can be discharged for a ranged touch attack dealing 1d8 +1 damage for every round it has been active, and has a minute per level duration, which means if stretched it can get to +10 damage per level, which is +60 per hour. If one were to persist it and discharge it after 8 hours, it should deal 1d8+480. I realize that it is not the pinacle of blastomancy, but do have this right? Is my math wrong here?

[Cog]

You might have missed where Nimbus caps that +damage at your caster level.

[Apophis]

Unfortunately, max damage is capped at your caster level.

Edit-Ninja'd...

[Darth Stabber]

Okay, well that sucks. I thought I had an amusing little combo there, oh well. Too much work anyway, plus probably not worth a 5th lvl slot, nor turn attempts.

[Zaq]

Also, I'm pretty sure there's language somewhere saying that Persist can't be used on any spell that can be discharged. I don't feel like looking it up, but I'm pretty sure that's what killed Chuck.

[Jack_Simth]

So nimbus of light acts as a light that can be discharged for a ranged touch attack dealing 1d8 +1 damage for every round it has been active, and has a minute per level duration, which means if stretched it can get to +10 damage per level, which is +60 per hour. If one were to persist it and discharge it after 8 hours, it should deal 1d8+480. I realize that it is not the pinacle of blastomancy, but do have this right? Is my math wrong here?
Persistent Spell (http://www.d20srd.org/srd/divine/divineAbilitiesFeats.htm#persistentSpell) can't be applied to spells who's effects can be discharged:

A persistent spell has a duration of 24 hours. The persistent spell must have a personal range or a fixed range. Spells of instantaneous duration cannot be affected by this feat, nor can spells whose effects are discharged. You need not concentrate on spells such as detect magic or detect thoughts to be aware of the mere presence of absence of the things detected, but you must still concentrate to gain additional information as normal. Concentration on such a spell is a standard action that does not provoke an attack of opportunity. A persistent spell uses up a spell slot six levels higher than the spell’s actual level. (Emphasis added)