Twelve Volt Battery Dead after 2 Week Holiday

[Joningy]

I purchased my ex-demo MG4 Trophy back in May, 5 months of stress free motoring. On returning from a 2 week holiday last weekend, car parked on my drive plugged in, only to discover the car was completely dead! Luckily, I've RAC cover, they tested the twelve volt battery, it was completely drained on any power. The RAC jumped started the car, I drove it to my local MG4 garage.

The garage workshop tested the twelve volt battery, all ok - and told me (I'm struggling to believe) apparently it isn't unusual for the twelve volt battery to be drained of power if left unattended for 2 weeks! The engineer recommended that someone jumps into the vehicle with the key to start it up if not driven for a couple of weeks! Which at home my daughter can do, however if parked up in an airport car park doesn't work!

Has anyone else experienced a similar issue and been told the same unlikely story / reason. It does seem rather far fetched!

Many thanks

Iain

This is aparently not just an MG EV problem, shortlly after buying my MG4 Trophy LR new in October 2023 and reading of other instances of 12V battery flat after leaving for a couple of weeks,

The solution is very simple and much quicker than waiting for a breakdown van to arrive. lots of savvy EV drivers have bought a small jump starter pack, it was around £40 and crucially small enough to keep under the driver's seat.

It's fairly important not to keep the jump starter in the boot, as the boot is difficult to open with a flat battery.

Fortunantely our car has never suffered the problem, despite 2 airport parking long stays of 4 weeks in Jan/feb.

But what just happened after 17 months without a single problem (except the horrific lane keep assist until the upgrade improved it) is the well reported drivers window not opening, but that was easily remedied by disconnecting the 12V battery and following the instructions elsewhere on this excellent forum.

 

[webhiker]

I left my MG4 ER unattended for 7 weeks (vacation and hospitalisation) last year without any issues at all. Jumped in the car and drove off immediately.

 

[Tuareg]

Also me, left my Xpower for 5 weeks in my driveway, 12V battery voltage remained the same throughout the duration, always reading between 12.5 - 12.8V through iSmart.

 

[Joningy]

This is apparently not just an MG EV problem, shortly after buying my MG4 Trophy LR new in October 2023 and reading of other instances of 12V battery flat after leaving for a couple of weeks,


The solution is 2-fold and very simple and much quicker than waiting for a breakdown van to arrive., firstly leave the car with more than 50% traction battery, I charge the car to over 90% ready for our drive home.

Secondly, lots of savvy EV drivers have bought a small jump starter pack, it was around £40 and crucially small enough to keep under the driver's seat.

It's fairly important not to keep the jump starter in the boot, the boot is difficult to open with a flat battery, the bonnet is a manual lever so not affected by the battery.

Fortunately our car has never suffered the problem, despite 2 airport parking long stays of 4 weeks in Jan/Feb.

But what just happened after 17 months without a single problem to now (except the horrific lane keep assist until the upgrade improved it) is the well reported drivers window suddenly not opening, but that was easily remedied by disconnecting the 12V battery and following the instructions elsewhere on this excellent forum.