So i got some new batteries and was going to try to cycle 4 packs in parallel, i set the charge and discharge to 10amps, charged all 4 battery's in less then 15mins. then started to cycle the battery with the discharge but i could not get above 3amp on discharge and was taking forever. i tried to hook only one battery up and the same result on the discharge only it would not go above 3amp. i also tried to set the discharge down to 5amps and still only 2.9 amp max discharge. am i missing something

The PowerLab 6 has a 50 watt internal discharging power limit. Im guessing you have 4S packs? Then around 3 amps is the limit.

To achieve higher discharge rates requires a regenerative setup, using a large enough rechargeable battery, for example a lead acid deep discharge marine battery. Basically the charger works in reverse and uses the lipo to put charge back in the power battery.

That makes sense and yes i was using a 4s, could i just charge them up then slowly run the car around for 5-6 mins at 1/5 trigger to cycle the packs before i race with them.

Opinions likely vary, but from what I've seen break-in is more of a plane/heli thing, I don't think many car guys worry about it too much. Fly guys frequently drain packs fairly quickly at high and more constant rates. Generally cars are a little easier with the on-off nature of throttle-brake and typically longer run times.

Either way it's advisable to be especially careful of limiting the depth of discharge on the first few charges from what I've seen. Which is good advice anyway, limiting how far the packs are ran down is good for cycle life.

Dave is right, opinions vary on this. Mine, just use them as you normally would with the exception of not running the voltage down real far the first few cycles. How far? Ask Dave, he'll give you a better answer than I can.