Unless doing a rough estimate with timer and flashlight you will need a device.
I notice the more authoritative posts here are usually using the CBA II. A google search shows it to be a dedicated analyzer that also allows connection to your pc.
The other option is to buy a hobby charger with discharge capability. Many of them have this capability, although the specs vary a lot on the discharge side. For this purpose I really like the Duratrax ICE as it gives a lot of options like cut-off voltage and high discharge rates. I am currently using a Hyperion 606i, which is a great charger, but it limits discharges to 1A or under with a set cut off voltage of 3 volts for lithium batts. I like the hobby chargers as you can get a rock solid charger AND have some battery testing capability.
