[Elecraft] amp draw on 20 watt tune?

[cyr999@extremezone.com]

Quoting Lyle Johnson <wa7gxd@fidalgo.net>:
 
> With the KPA100 installed, the K2/100 has a TUNE power level of 20
> watts.

Thanks Lyle - now, what does this mean as far as amp draw while tuning and 
using an external power source? Will it cause substanially less usage time then 
stock K2 with internal battery? In other words, if I operate all QRP in the 
field with the K2/100, but use more power to tune - how much will that shorten 
battery life? Assume that I don't get carried away with tuning for purposes of 
this question hi hi. Thanks for your help. 73/Tim