Replaced battery myself too. But what a mission it turned out to be when I found out that disconnecting the battery resets the cars computer, and idling etc.. Car just refused to idle properly anymore. I needed to take it in...
Best to use a battery saver to preserve all the electronics on a vehicle these days. One such device involves plugging a lead into the cig plug with ignition on. Some of the jumpstart packs support this. Any battery supplier worth their salt will use a battery saver these days when they replace a battery.
Yea, learn something new every day. Thats a mistake learned for next time.
Another reason why I look at fluids and air only now. The cars we own have sensors up the wazoo, with cameras, radar for adaptive cruise and braking, etc etc. it is just not worth the risk to save a few dollars.