Brake failure

Hi all,

My first time here!

I want to see if anyone else has had a similar issue - I was driving on the motorway when these lights lit up, exactly the same as in this post

When I went to test the brakes, to my horror, there was no braking power at all! Thank goodness traffic wasn't that heavy and I managed to get home whilst going slower...and using pure inertia and friction to stop at the junction exit. Pressing the pedal right down to the floor released whatever little braking the car did have.

Called the AA man who could not find the problem - but noticed that the brake fluid level was low so there was a leak somewhere but yet all the brake discs were dry.
They took it to the Toyota dealership who have now said it was a battery issue...
My question is how does the battery have anything to do with the physical brakes? From posts here and the one quoted above it seems that there is a connection?

Suffice to say that this is a scary experience, especially when at speed...but sadly it is not the first time it has happened as last year, the brake calliper broke and I experienced the loss of braking power once again...this time the entire dash lit up with a constant beep sound (none this time round). That time I dragged to a stop on the hard shoulder to get towed up and the AA man who showed up said it should never have fallen off like that and blamed the dealer at the last service, who blamed someone else tampering....

Time for a Suzuki...?