In version BotBanish 3.6.xx you will need to replace a file in the BotBanish/bot/Subs/ folder to eliminate writing ip and user agent entries into the .htaccess file with the attached file.
You will also need to remove all entries in the .htaccess file between the tags
# * * * * * BotBanish IP Start * * * * *
# * * * * * BotBanish IP End * * * * *
AND
# * * * * * BotBanish BOT Start (REWRITECOND) * * * * *
# * * * * * BotBanish BOT End (REWRITECOND) * * * * *
This will decrease the size of your .htaccess file to a normal size and BotBanish will not add new entries to it after replacing the BotBanish_Subs.php file. This will also fix the error if you loose access to your site because of a 503 error due to an error in the .htaccess update.