A car that has not moved for a while is behind a large share of the flat batteries we see in Dublin. Back from a fortnight away. A second car that only does the weekend shop. A car left on the drive while you work from the kitchen table. It started perfectly the last time, and now it only clicks.
A parked car is never fully off
A modern car keeps a few things awake after you lock it: the alarm, the receiver that listens for the key, the memory for the clock, radio and seats, and on many cars a small data unit for the manufacturer’s app. Each one sips a little current. A healthy, fully charged battery copes with that for a good while. An older battery, or one already run down by short trips, may not get through two weeks, and a cold spell shortens that again.
Things that drain it faster
- A dash cam wired to stay on in parking mode
- A tracker fitted for an insurer or a fleet
- A boot, glovebox or vanity mirror light that does not switch off
- A charger or gadget left in a socket that stays live with the engine off
- A keyless fob kept on a hook just inside the front door: on some cars, a key within a few metres keeps the car checking for it
Before you go away
- If you can, give the car a proper drive of half an hour or so in the days before you leave, so it starts the break full
- Switch the dash cam’s parking mode off, or unplug it
- Keep the keyless fob well away from the car
- For a long absence, a smart charger or battery maintainer keeps a car on a private driveway topped up. Only run a cable where it is safe, never across a public footpath
- If someone can drive the car while you are away, a real run helps. Five minutes of idling on the drive does very little
Flying from Dublin Airport
Cars left in long-stay car parks for a week or two do come back with a flat battery. If yours will not start when you land, tell us the name of the car park and the zone or row you parked in. Car park operators have their own rules about access and assistance, so it is worth asking at the help point too. We will say on the phone if the car is somewhere we can reach.
Working from home, or a car that rarely leaves the estate
A car that only does the school run or a short trip to the shops a couple of times a week never gets back to full. Over a winter that adds up, and the first frosty morning finds the gap. Once a week, a longer drive at a steady speed, out on the M50 or a dual carriageway, puts back what the short hops take out.
Signs it is the battery, and not something else
A battery that ran down while the car sat usually gives itself away. The fob will not unlock the doors, the dashboard glows weakly, the hazard lights blink faintly, or the car just clicks. If the doors unlock as normal and the engine turns at its usual speed without firing, the battery is not what is wrong, and a jump will not help. Tell us which it is when you ring.
Is a jump start enough?
Usually, yes, if the battery was healthy and simply sat for too long. After the jump, drive for around half an hour. If it goes flat again within a day or two of normal driving, the battery is probably worn out.
Our page on when a jump start is not enough covers what we look at, and an electric car that has been parked up has its own quirk: see electric and hybrid cars.
Getting going again
Flat battery in Dublin, Meath or Wicklow after the car sat for a while? It is €120 for the call-out, with no extra for the distance, and you hear that before anyone leaves.
Call 085 783 9202