I need to brew 2 beers in one day (single vessel BIAB)

I need to brew 2 beers in one day this weekend. I have a 11gal eBIAB setup.

I was thinking of doing it like this, please let me know if I should change something.

Heat strike water for first brew and dough into regular cooler (no screen, no manifold, etc). While that is mashing, heat and maintain strike water for 2nd batch.

Once 1st brew is mashed, drain 2nd strike water into 2 buckets and empty contents of cooler (water and grain) into basket and bag in kettle and heat to mash-out temp, remove grain and boil as usual.

While 1st brew is mashing out and boiling, transfer strike water for 2nd brew from buckets into cooler and dough in 2nd batch.

If my 2nd mash lasts longer than it should, there shouldn't be any adverse reactions, correct?

Any thing I should do differently?

Seems fine, youd probably want to do some sort of infusion when your second mash is done to serve as a mash out or the starches will contine to convert as your temperature continues to drop in the cooler. It shouldnt take much boiling water to bring it all up to mashout so a standard pot in your kitchen would probably work.

I think you are trying to move too much water around IMHO. By the time you have moved water to buckets, and then to a cooler I think you will have lost a lot of heat. I would get a mash going in the cooler, then get a mash going in your kettle BIAB. Complete the BIAB batch in the kettle and then transfer the mash in the cooler to your BIAB kettle for sparging / straining.

With this method you likely will have about a three hour mash in the cooler, this is not a problem IMO. You might want to keep a tea kettle of hot / boiling water at hand if you need to bump the cooler up a few degrees to maintain temperature a little bit during the long mash. Keep it simple

Thanks for the info.

Good idea wilserbrewer, I think I will do just that and not have to move so much water around. One brew is a Hefe with a 90 minute mash anyways, so it won't be too much longer than normal.

I was going to suggest bringing your strike water higher for your 2nd batch. You can always cool off with some ice cubes if the anticipated heat loss doesn't occur.