I have a 3 cell lipo 1300MAh battery. I also have a celectra lipo charger. The options that I have on the charger are: 2.0A,1.5A, 1A, 500mA and 250mA. I have a cell selector for 1-2 and 3 cells. What should I set the charger on. Sorry for this, but I don't have any instruction manual. Thanks

You don't want to charge over 1C (1x capacity). Therefore, a three cell 1.3 amp battery should charge at 1 amp on the three cell setting.

The prefix milli is 10^(-3). 1000mA = 1A
micro (symbol mew) is 10^(-6).
The exponents are multiples of three because it is engineering notation.

Going the other way
kilo (K) = 10^3
mega (M) = 10^6

The 1A setting will work but the 500mA setting will be even gentler on the battery.

Yes, there is evidence to support that going down to .7C will extend battery life. Going lower won't add anything, but won't hurt either. At the 1A setting you will be charging at .77C, which is close. 500mA will take noticably longer for not much additional gain in lifespan. The choice is yours.

Makes sense. I was thinking about charging at 1c vs. 1/2c, forgetting that it is a 1300mAh battery. Being a 1300mAh battery, 1A is less than 1C so 500m would be considerably less than 1/2.