I have a Blade cp, What lipo can or should i use?

Depends on what type of flying you do.

In my opinion...

A beginner that is hovering and doing mild FF will enjoy the long flight times provided by a larger battery such as a 1320mah 3S (ThunderPower makes great batteries).

For 3Ding go smaller like 900mah 3S. Shorter flight times, but much less weight so you can crank it around.

HTH

From what i've read. The stability is the only thing a larger lipo gives you. They take more power to hover because of the weight. And people with 700-800mAh lipos get about the same as ones with the higher mAh lipos.(but i could be wrong, i haven't really used a lipo on my blade)

I have no plans on 3d just want to learn scale flying and longer run time is better right? Anyone run a 1300? I just want to be sure it can handle the extra volts

It can handle 3 cell lipos. But you need to get a 9 tooth pinion motor to keep the head speed down.

A higher capcity pack will make it as stable as the stock nimh, but with more power. The smaller ones make it not as stable, but more manuverable.

I have a Thunder Power 3S 1320mah lipo with 8t pinion, and can hover for about 25-30 mins. You ain't gonna do that with an 800-900

I read somewhere someone got 24 minutes with a 710.

But for just hovering and some forward flight 1300 or so is fine.

Sounds great......... who am I kidding I'll probably crash in less then 2 minutes