Hey guys. Hope someone maybe able to give me some guidance on likely cause of this issue:

* I'm getting a Low Battery, Start Engine message when entering or exiting the car
* However the car sits on a battery conditioner all the time, hard wired to the junction box in the boot (not direct to battery)
* battery conditioner showing its charged up?
* battery level indicator in the boot suggests low voltage even though its on charge.
* if I run the car for a good 45mins I don't get the warning message for a good week or so
* AA breakdown have tested the battery on two occasions, each time their machine says it's fine (I'm not convinced)
* Battery is the original that is now 5+ years old (so what I thought it would be)
* AA tested for a drain, but it was tricky as with the boot open the light is on. So their machine showed a very slight drain but everything wasn't shut down.
* and the drain would have to be drawing more current than the battery conditioner? It wasn't anywhere near that high.

Any ideas? Alternator is obviously ok. I still think battery? But their "computer says no" I have Parts and Labour cover with the AA so if it was deemed to be the battery they'd have to pay for a new one, at £200+

 

Its a 5yr old battery, it is absolutely the battery I say.

I suspect its holding a charge but its output ability is not what it once was, hence it not dishing out the full voltage the car needs to operate properly and these cars get pretty funny about batteries not dishing out full juice.

 

Five years for a battery on a car with all the modern electronics is quite a lot, in my admittedly limited experience. Most of my cars are/were before the current generation, where 5 years was typical for a well-cared for battery. My 2012 Volvo's gave up in under three and I'm on the second in my 2016 F-Type.

 

Got 7 years on my Range Rover Sport so did pretty well there. My F Type is 4 years old now so lets see how long before I start getting issues.

OP - this isn't the OBD port battery drain issue is it?

 

Thanks for the input so far all

What is this issue?

 

If your OBD port has been recently tapped into, it is likely that the battery management system needs to be rebooted by disconnecting the battery for 15+ seconds.

 

Don't want to state the obvious but are you sure it not the key fob battery as this has a dash warning light to tell you when the key battery is low?

 

I would assume that AA are competent to test your battery, usually I believe the battery would be disconnected from car before load testing which places a load on the battery and monitors how much the voltage drops under load over a certain time

As others have suggested modern batteries can last longer than earlier batteries, provided they aren't heavily discharged or left discharged .

If you do need a new battery, good quality battery available for below £200.

see this

 

I found that getting an OBD2 Bi Directional code reader and resetting the Battery Management System solved all my battery woes. For some reason, the computer leaves some systems operational 24/7 if it doesn't get reset when the battery gets replaced or if an ODB2 device is disconnected in some sort of way.