My car (a Toyota Avensis 2001 Diesel 2.0L) often lays idle for long periods. During these periods the battery runs down and it is unable to start. I recognise that the car should be driven more often but unfortunately it is not possible sometimes.

I have a portable jump starter device (http://www.walter-service.at/index.php?page=product&info=1604) that I have used for previous car, however it does not work with this car.

It has been suggested to me that a device with a higher current might be more capable of starting the car. Is this true? If so, how can I determine if the current is large enough for my car?

In summary, how can I best choose a jump starter which is suitable for a car?

  • Looks like your battery is a 70amp/hr battery and that booster only provides 17.2amp/hr - it wont provide enough cranking power with that amperage even though the voltage is right.
    – Mauro
    Commented Jan 7, 2015 at 9:26
  • 1
    @Mauro amp/hr's have no bearing on cranking power. amp/hr is kind of a unit of how much energy a battery can hold. A large car battery can obviously hold more energy than a small, portable battery. For a cranking power comparison (which is what you need to start a vehicle), you want to look at the cold cranking amps (CCA) number of the vehicle battery and the "Peak Amps" on those portable chargers. Commented Jul 10, 2015 at 17:08

1 Answer 1


It sounds like you need a trickle charger or battery maintainer - this is a small charger than monitors the charge on the battery, and keeps it charged. Most modern cars have electronics that have a continuous drain on the battery - a trickle charger produces enough power to compensate for this drain, so that even if the car isn't driven for a few weeks the battery doesn't drain completely. This will also help ensure a longer life for the battery.

In addition to the plug-in models, there are also solar-powered versions, so even if you don't have a power source available you can still keep the battery charged.

Make sure you get one that has "intelligence", so that the battery does not get over-charged.

  • 2
    This is very good, sound advice. Commented Jan 5, 2015 at 1:53
  • I cannot be sure if this answers my question. My question is related to jump starters (are trickle chargers the same as jump starters). Does a trickle charger need to be connected to the mains? Will a trickle charger start a car whose battery is dead?
    – punkle
    Commented Jan 6, 2015 at 20:15
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    It doesn't really answer your question. You described a problem, and asked a question about how to deal with a symptom of the problem. I think you should address the root cause of the problem, not the symptom, but it's your call.
    – chris
    Commented Jan 7, 2015 at 2:52

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