- A car battery drains slowly when the car stands still for a long time. After two to four weeks it can be too empty to start.
- Parasitic drain from the alarm, keyless system and onboard computer drains the battery, even with the ignition off.
- Summer heat speeds up wear. Store your jumpstarter cool, not in a scorching hot boot or glove compartment.
- A charged jumpstarter at home gets your car started again in seconds after a holiday or storage.
You come back from holiday or take the car out of storage, and it won't start. Sounds familiar. A battery that stands still for a long time drains slowly. In summer, the heat plays a role too. Below you'll read why that happens and how you simply prevent it.
Why does a battery drain when the car stands still?
Even with the ignition off, your car keeps using power. The alarm, the keyless receiver, the onboard computer and the clock continuously draw a small amount. That's called parasitic drain. If you drive regularly, the alternator recharges everything again. If the car stands still for weeks, there's nothing to recharge it and the voltage keeps dropping. A battery that's already a bit older reaches that point faster. You can read more about the causes in car won't start.
What does summer heat do to your battery?
Heat is bad for a battery. At high temperatures moisture evaporates and the plates wear out faster. A car baking in full sun therefore ages its battery faster than you'd think. The same applies to your jumpstarter. A lithium jumpstarter works best between roughly 10 and 30 degrees. If you leave it in a scorching hot glove compartment, that costs it lifespan. Store it cool and dry.
How do you notice your battery is already getting weak?
A battery often gives off signals before it truly leaves you stranded. The starter motor turns more slowly than normal, especially in the morning. Your lights dim briefly the moment you start. Or the car only fires up on the second attempt. If you notice this after a period of standing still, the battery is probably near the end of its life. Have it tested at a garage before you travel. A jumpstarter helps you get going again in the moment, but you replace a worn battery in good time. That way you prevent standing still again halfway through your holiday.
This is how you prevent a dead battery after standing still
- Drive it full: take a drive of at least twenty minutes just before a long period of standing still.
- Trickle charger: connect a maintenance charger during storage that keeps the battery topped up.
- Disconnect the negative terminal: no charger nearby? Disconnect the negative terminal to stop the parasitic drain.
- Charge your jumpstarter: charge it before you leave and store it somewhere cool.
- Store it cool: not in full sun, the hot boot or the glove compartment.
What if it's dead anyway?
If the car has been standing still and won't start, a jumpstarter is the fastest solution. You don't have to wait for a second car or roadside assistance. Connecting takes three steps: you put the smart clamps directly on the battery, red on the positive terminal and black on the negative terminal, you wait until the screen shows 12V Ready, and then you start. The clamps are protected against sparks and incorrect connection. If the cables are too short to reach the battery, check out cables too short.
Don't leave a drained battery empty for weeks. Deep discharge permanently damages the battery. Charge it right after starting with a drive or a charger.
Which jumpstarter is handy after a long period of standing still?
For an average petrol car, the Boost Mini 3750 with 620 CCA (Cold Cranking Amps, the real starting power at a cold start) is more than enough. If you drive a diesel, SUV or camper, go heavier, towards the Boost Pro 8250 with 960 CCA. If you also want to be able to pump up your tires after storage, a model with a compressor is handy, such as the Boost Air Micro.
- Starting power: 620 CCA, suitable for most petrol cars.
- ForceStart: forces a start attempt on a deeply discharged battery.
- Compact: fits in the glove compartment, with power bank and flashlight.
Frequently asked questions
How long can a car stand still before the battery is dead?
Often two to four weeks, depending on the age of the battery and the parasitic drain. An older battery becomes too empty to start sooner.
Should I disconnect the battery during long-term storage?
You can, because it stops the parasitic drain. A maintenance charger is easier, because it keeps the battery topped up automatically.
Is heat or cold worse for the battery?
Both. Heat speeds up wear, cold lowers the available CCA at the moment of starting. Both increase the chance of a dead battery.
Can a jumpstarter start a deeply discharged battery?
Yes, with the ForceStart function. Charge the battery right after, because deep discharge is bad for the battery.
Where do I store my jumpstarter in summer?
Cool and dry, between roughly 10 and 30 degrees. Not in a hot car or glove compartment, that costs lifespan.
