2009 Toyota Highlander electrical dead

All electrical dead. Could not jump start battery even with a booster charger. Replaced battery & started fine w/ no problems. Why couldn’t the technician jumpstart with dead battery in place?

Dead cell in battery that would not let current through.

Thanks. AAA tech had no idea why there was a problem.

That’s is because he really isn’t a “tech”. He is a guy who jumps or tows car for a living. Not his area of expertise.

Valid point! Thanks.