Set your charger for charging a 2-cell pack, some say 7.4V some say 8.4V. Then set the capacity at your respective battery's capacity, 2000 or 2100. Most chargers will automatically set charge current based on this number. Most battery manufacturers recommend a maximum charge current of 1C, which is represented by your capacity: 2000 milliamp-hours(mAh) equals 2.0 amps charge, 2100 milliamp-hours(mAh) equals 2.1 amps. For maximum battery life and safety stick to these values. Some batteries can handle up to 2C (2 x capacity in amps), but it does effect battery life and unless your racing, the benefits are minimal and therefore not recommended.

To summarize, Charge the Losi battery at 2.0 Amps, the Reedy at 2.1 Amps. Be sure to set the battery type to LIPO 2-cell or 7.4V. Max voltage will be 8.4 volts. This should get you the basics, the rest should be in your charger manual. If you do not have one, I believe you can download them at the venom website.