Alarm sets off when I unlock my car using the fob

[amison]

I bought this Toyota Auris Hybrid in end May, it's a 2013 model. For some time things were alright, but then 1 of the fob had low Battery as it would not do anything like lock/unlock. So I changed the Battery. But in mean time I started using the 2nd fob, which after sometime gave trouble, the alarm on the car would set off when I unlock the car using the 2nd fob. So I started using the 1st one again. But after some time, this one also gave the same problem ( mind it, it has new Battery which is not even 1 month old). In this situation, I would like to mention that the alarm would not set off like everytime, it's on its mood😊. So last Thursday I changed battery on both fob, and I used the first fob and bang, the alarm set off again. Next day I used the 2nd fob and the alarm did not set this time. I'm getting bit confused as to what might be the issue. If someone could give expert advise please.

 

[FROSTYBALLS]

How old is the car's 12v Battery?

[amison]

@FROSTYBALLSit's a 2013 model, so I believe it's that old, but I recently got car serviced with Toyota and they have issued me with a certificate of hybrid health check

[FROSTYBALLS]

However the 12v Battery is separate to the hybrid health check - it isn't the hybrid Battery.

[Catlover]

Hi Amit, can I ask…. How often do you use the car?  And when you do use it what sort of mileage do you do per journey?

[amison]

11 hours ago, FROSTYBALLS said:

However the 12v Battery is separate to the hybrid health check - it isn't the hybrid Battery.

I have no clue than, you reckon I should get the Battery checked?

[amison]

@Catlovermy weekly mileage is approx 20 miles over 3 days, I usually drive 1 day during week and then weekend

[Catlover]

Amit, may i suggest that the use/mileage you do during the week would not be enough to put much energy back into the 12v Battery (in the hatch area, right hand side, under the carpet and cover). Come the winter time, cold weather which affects all batteries (even a torch battery) may affect your 12v badly. The 12v sets off a few features including lighting up the dashboard preparing your car to start. If the 12v gets depleted that initial sequence won’t start.  You could go to a good Battery supply business who will load test the 12v Battery to see what state it is in.          
In Auris hybrid cars, with the 12v battery being within the vehicle cab/passenger area, for safety reasons (there is acid in “normal” batteries which in the event of an accident could spray people in the car) the battery is an AGM type. These cost about £160.          
You could probably be best to have battery checked anyway, but whether that is the exact cause of your problem….. maybe, but difficult to say definitely.          
An alternative to getting a new battery is to purchase a slow battery charger, not just any battery charger but a slow one. Slow charging is better for modern day batteries. Highly recommended by more then a few members of this forum is a CTEK MXS 5 slow battery charger. These cost around £70 but are an investment which, if looked after, should last for years. I personally recommend a battery company called TAYNA in Abergele north Wales as a supplier. Order/pay on the internet or over phone and deliver within 2 working days. That will charge your battery, and even recondition it (if it has not deteriorated too much). A battery in a poor state could take 6 or 7 hours to do that.      
Whether or not it is your 12v battery causing your fob problem or not, whether or not your battery needs renewing or not, there is a strong chance come this winter you will have the 12v battery fail on you.             
Let us know how you get on.

 

[amison]

@Catloverthanks, really appreciate your advise