12 volt battery draining overnight

[Hpaul]

Had problem with 12v Battery on my 2012 Prius a couple of weeks ago - not enough charge to start computer. AA man diagnosed probable failure of some Battery cells. Took it to local Toyota centre who replaced Battery. 
Two days later battery was totally flat. AA man said there was something draining the battery even when the car was shut down. Toyota have had the car for a week now, trying to find the source of the drain. Very frustrating. Anyone else had this problem?

[TonyHSD]

Hi, 

are they any insurance black box fitted, cameras, aftermarket alarm or any additional device that may need electric power even when the car is off? You have to start from there, anything done by the previous owner. , but dealers should be able to trace it. Difficult to guess what can it be, whoever is with the car has greater chances of finding the fault. 
Good luck.

[Roy124]

How long had you had the car before the first failure?  That the second failure 2 days after the first on the new Battery suggests a new problem not an old one. 

The traditional problem is interior lights or boot lights. Then the car key issue might be a cause. 

What changed before the first failure?

[Hpaul]

Nothing changed before the first failure. Had the car for five years. Dashcam is fitted but the socket it uses is not live when car shuts down. Toyota still investigating.

[Hpaul]

An update. Toyota had car for two weeks and said that they couldn’t find the fault and suggested that I take it to the auto electrician next door to them. This I did. The electrician found and sorted the problem in half a day. Turned out to be a fault in the audio system. 

[Cyker]

Care to give them a plug? Always good to have the details of a competent auto electrician!

 

[Hpaul]

Company is Westlec, based in Patchway Bristol. Very reasonable rates.