My Honda Civic died after the temperature dropped lower than -30°C, and will only start now when I boost it. The previous owner told me about this, and he said he replaced the battery. But now, it's doing the same thing again only a year later. I'm wondering if it's something else?

  • 2
    Are you using an engine/block heater at that temperature? – Pᴀᴜʟsᴛᴇʀ2 Jan 6 '15 at 12:14
  • 1
    Car batteries only last a few years, and winter does seem to get the best of them. – GettingNifty Jan 7 '15 at 9:07

The batteries on the cars will not have good cranking power especially if it is cold outside. My car does that too.

I usually jump it and it starts and runs fine, what I suggest you to do is

  1. Throw a battery tender on it as long as it is parked.

  2. Get the battery load tested, most automotive shops do it for free, if not you can buy one at the HFT for about 20 bucks and have it for you for ever. As said by @GettingNifty car batteries usually last about 3 to 6 years, depending on the manufacturer.

  3. Make sure your car doesn't have any shorts or draw of current when not in use. to do this use an ammeter in series to the battery positive, the draw should not be more, I think not more than a couple amps.

  • You may want to explain what HFT is to those who exist outside of the States. – Pᴀᴜʟsᴛᴇʀ2 Feb 29 '16 at 23:41
  • I am sorry for not writing what HFT means, I was thinking as if I was writing in a local forum or some like that. HFT - Harbor Freight Tools (A store with a lot of low priced tools ), I am not sure if they are outside US. – kasey Mar 1 '16 at 2:04
  • I's also add to check that your voltage regulator isn't bad and overcharging and reducing the life of your battery. Check the voltage of the battery while the engine is running. It should be between 13-15 volts. Rev the engine and hold it a bit to make sure it's not going over 15V at higher RPMs. – Mysterfxit Mar 1 '16 at 4:30

Lead-acid batteries contain a solution of sulfuric acid (H2SO4) and water -- the solution is referred to as the battery's electrolyte. Adding a solute (in this case, H2SO4) to a solvent (in this case, H2O) will lower the freezing point of a solution. A fully charged battery has more H2SO4 than a discharged battery. The additional H2SO4 depresses the freezing point of the batteries electrolyte to around -70 °C
However, a discharged battery's freezing point rises to ~-10 °C. A discharged battery will freeze -- a charged battery will not freeze. A battery that has been frozen is very likely a dead battery.

For further info: http://mathscinotes.com/2013/02/battery-freezing-math/

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