I'm trying to jump start my car with a portable booster pack, the car has been out for about 2 weeks in temperatures that regularly reach -15 C and the battery is completely dead. It's a brand new battery I bought a month ago. Normally when I place the cables on positive and negative, I get a clicking sound and the LEDs on the booster start pulsing. I don't get that now, and the battery doesn't charge, unless I engage the manual override on the booster. Is this a consequence of the cold weather? What can I do to start my car? As it stands the booster does nothing but drain itself out and power the dash/lights.

  • Welcome to Motor Vehicle Maintenance & Repair! You may want to start by disconnecting your battery and bringing it indoors so it can completely warm up. By doing so, you'll be able to get a lot more juice out of it. You can also try to get a complete charge on it, but you'd not want to do that inside because it will emit hydrogen gas during the charging process. Also, if you routinely reach -15° C, you most likely have some type of block heater ... you may try using that to give everything an even chance to get working. Jan 10, 2022 at 13:16

1 Answer 1


The booster pack with manual override sounds like it is working fine. However, something on your car is trying to kill it just like it tried to kill your new battery. Like a heavy short circuit or a bad starter. Disconnect the negative battery post (or remove the battery completely) and charge it fully. Then you need to isolate and fix the electrical fault.

  • The booster pack doesn't detect a battery if the voltage is below 2V and by itself doesn't have enough juice to boost my car from close to 0 volts.
    – user47989
    Jan 10, 2022 at 3:29
  • If here was a 'heavy short circuit' to draw a large current, then surely you would either have something obvious turned on that shouldn't be on, like the lights, or otherwise you would be seeing smoke somewhere. The large current has to go somewhere.
    – HandyHowie
    Jan 10, 2022 at 9:27

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