Which Lipo C to get?

[JBL]

I currently race a 2wd buggy, which C rating Lipo should I get? Is a 30C too much or would a lower C rating be more suitable?

[c0sie]

The higher the C the better really.

Summat along the lines of 3200mah(ish) and 30C would be ideal for racing 2WD with say a 6.5 motor.

[JBL]

Would a higher C rating give me too much punch? Thats my only reasoning in buying a lower C rating such as a 20C or 25C.

[c0sie]

Ideally you want a high C rating so that your motor/ESC system doesnt try and draw large amounts of current from a pack that cannot handle the amp draw.

High C with low capacity will not offer high ammounts of punch, and if you do struggle have a look at changing your motor

[matdodd]

Ive found theres not much diffrance between running a 7.5 with 30c & a 6.5 and 20c!

[glypo]

Talking about C rates and punch completely ignores the whole point of a C rating. It is nothing to do with punch! A 30C pack isn't any faster than a 20C pack...

Just because your battery can deliver a lot of current, doesn't mean your motor or ESC will draw it. If your battery is so poor that it can not supply enough current and thus your punch is reduced, it means your are operating your battery beyond its limits and is potentially VERY dangerous.

Never ever use a low C rating to reduce performance, use a slow motor, steady thumb or radio/ESC limitation.

For my explanation of C rates:
http://www.glypo.com/guides/lipo/

[Dagger Thrasher]

Never ever use a low C rating to reduce performance, use a slow motor, steady thumb or radio/ESC limitation.

Truer words were never spoken. Doing this can be very dangerous, and at the least could ruin your LiPo pack.

The C rating of a pack is just referring to the amount of current that pack can safely discharge whilst keeping good voltage, so the higher, the better (though there are always some manufacturers who over-rate their packs). You'd want at least a 20C-rated pack if you're going with 3200mah capacity, but preferably higher.
If you're running a hot motor (like a 3.5T, for example), then a pack of the same capacity with a higher C-rating will often provide more "punch". This is just because the higher-rated pack isn't having to work as hard to produce the required current, and as a result can sustain higher voltage...though this isn't really noticeable on slower motors like a 5.5T or above as neither pack will be struggling.
A pack with a higher capacity but same C-rating will have the same effect. Also, having a pack with a higher C rating than the bare minimum will allow it to run under less strain, and ultimately have a longer life.

Remember that C-ratings are relative to the pack's capacity, so a 20C-rated 6000mah pack would be able to safely supply more current, if required, than a 30C 3200mah pack.

Don't go by C ratings alone, though; one manufacturer's 30C-constant rated pack might perform way better than another manufacturer's. Sorry, I'm writing you an essay here. What motor will you be running?