1c or 2c... are they magic #'s
 

I was wondering with charging lipos. We have smc 5200 2s lipos. 1c would be a charge rate of 5.2 and 2c would be 10.4. Now 2 of are chargers only go to 5 amps so we charge them on that. Now I just got a charger that will go to 10 amps, still not enough to do 2c.

Does it matter if you don't charge it exactly at 1 or 2c?

These packs will be fine charged at 5 amps. The 2C charge rating doesn't make much difference on most chargers anyway. The CC/CV charge system for lipos means that it will only charge at the higher rate up until it hits 8.4 V, then the charger backs off the voltage and amps to only what the battery can drink.
In my experience it's rare for the packs to continue to charge at a full 1C once it's hit 8.4V, much less 2C. If your charger has a display you can watch the charge rate slowly drop as the pack nears full capacity. On our ICE's, it drops to around 0.1 amps by the end.

The only diff is charge time. 2C charging will be a little quicker than 1C so you'll save some time and not have to wait as long for the lipo to finish. Its no double due to the CC/CV charing lipo uses. It shortens the CC part, but the CV part still takes most of the time.

Also keep in mind even though a battery is rated for up to 2C charging that it will still significantly shorten its life charging at that rate.

Most the time we will only charge at 1c. I just didn't know if it affected like the discharge rate or anything. Everything I've always read was like "charge at 1c", never "charge up to 1c". Which would make it a little clearer.

NO your good, 0.8C is fine or 0.5C, it should be stated as "up to 1C" like you mentioned.