Pretty cool electrical tip for weak batteries

[Black1987Stang]

my friend was starting up his mom's car in his garage so i can put my car in there to work on it, it barely cranked, was very cold out, he put on the headlights for less than a minute, supposed to get the electrons moving inside the battery since it was stone cold dead.....went to go crank it and it started right up...I was like ....Thought that was pretty slick, just sharing my experience

 

[86bluecobra]

wow that is cool. I'll try it next time i go to fire up my stang after it has sat the winter.

 

[stang&2Birds]

BAD advice! That worked because there was crud between the battery terminal and the cable terminal. In general, that will KILL a weak battery faster.

 

[Black1987Stang]

BAD advice! That worked because there was crud between the battery terminal and the cable terminal. In general, that will KILL a weak battery faster.

how would the crud make it work?

 

[millhouse]

BAD advice! That worked because there was crud between the battery terminal and the cable terminal. In general, that will KILL a weak battery faster.

Actually, I do recall my high school physics teacher ranting about the same thing. It's been far to long (and perhaps a few to many bong hits) since my school days, but there is some science behind it.

 

[JimBowy]

i seem to recall this having more to do with the resistance in the battery
when you turn on the headlights you are heating up the battery, a warmer battery has less resistance and thats why you have a better chance of starting the car

 

[stang&2Birds]

i seem to recall this having more to do with the resistance in the battery
when you turn on the headlights you are heating up the battery, a warmer battery has less resistance and thats why you have a better chance of starting the car

That's the false thought. A colder battery is weaker. By turning on the headlights, the battery is "suppose" to heat up. That means there is less lost because of the battery's temp.

Well, that work for a *Battery Warmer*. For a cold battery, it's the resistance between ALL of the contact points that will get effected by that short turn-off. The battery won't heat up much from the MINOR load of the headlights. But, poor connections MAY lower their resistance once current starts to flow.

In general, it's a hack. It may or may not work. It's best to have a good battery, CLEAN connection with di-electric grease, and so on.

As for all of the "battery warmer" theories, ask them if they've every used a high resolution infer-red thermometer. And, then ask them if the battery's ability at the "new" temp, if it even heats up, is much different. Of course, to *properly* test, the battery gets put in a thermal chamber and is held at that temp for an hour then tested.

 

[bloopbloob]

i'm in my third year of my Bachelor of Science degree, which means i have taken a **** load of chemistry and physics courses.... and there is no science behind that claim. yes a warmer battery will have more energy, but the idea of using a battery's own energy to increase it's energy output is just silly. by turning on the headlights you do not increase the potential energy of the battery, you lower it! the only explanation for what you are describing is possibly a bad connection. The increased output due to the headlights being on may have created a better connection through the terminal 'crud', but does not increase the battery power. i think just a good cleaning is better advice!

 

[gunmetal5.0]

Hey Bloop nice car, could be improved by taking those mudflaps off? Maybe lowering it a tasteful 1.5 inches.

 

[fastranger347]

bloop bloop is right, draining the battery to increase its output is nearly the same concept a perpetual motion, which is a joke