When you jump starting a vehicle why is it you are supposed to connect the negative jumper cable to a ground instead of the negative terminal of the dead battery?
2007-09-08 03:22:08 · 16 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
There are fumes that come from the battery that can ignite. When you connect the second cable you complete the circuit causing current to flow. As you connect or disconnect the cable there is a likelyhood that you will cause sparks which could ignite the fumes causing the battery to potentialy flash. If the lead is away from the battery the sparks are still there but the chances of having a battery fire are greatly diminished. And as to the answers above, yes the car will start just as well if you connect to the battery directly, but you are taking an unnecessary risk.
2007-09-08 03:27:55 · answer #1 · answered by georges10 3 · 0⤊ 0⤋
When battery voltage drops in a car it sulfates and emits a highly explosive gas. Therefore is best to connect the positive ground of the cable to the dead bettery and the negative clamp to a clean ground elsewhere away from the battery. You'll always notice a small spark when you do this but it's enough to blast a dead battery wide open. I've seen batteries explode laying on a shop floor if there are welding or grinding sparks around.
2007-09-08 04:41:10 · answer #2 · answered by Country Boy 7 · 0⤊ 0⤋
Once you have a battery BLOW UP . you will understand .
Cars use the metal frame and engine itself to complete the electric circuit back to the battery. The negative terminal is wired directly to the engine. That is why you can connect the negative terminal to the engine. That bolt where the battery connects is a good place, usually to attach the negative cable. This is why you don't want the cars to touch, you don't want to allow the current to pass from one car to the other that way.. you want it through the cable.
When batteries charge, especially when they are charging quickly, they split some of the water in the battery into Hydrogen and Oxygen. The Hydrogen is explosive, and a stray spark from you connecting or disconnecting a cable can set it off. This is not a very likely hazard, but it is one you don't need to mess with. That is why the last cable is attached to the engine a little ways from the battery, where there is not likely to be any explosive concentration of Hydrogen.
2007-09-08 03:28:29 · answer #3 · answered by jon_wayne89 5 · 3⤊ 1⤋
Batteries can generate an explosive gas. A spark can ignite said explosive gas, causing your battery to blow up and getting acid on anything close, including you.
So, you connect the positive to positive first, then the negative wherever (negative post there is fine) on the vehicle you are using to jump yours, then to a ground some distance from the battery so that, if there is a spark, it is no where near the vent caps on the battery. Just for safety reasons.
2007-09-08 03:37:51 · answer #4 · answered by oklatom 7 · 0⤊ 0⤋
Older vehicles typically just have an exposed battery (no plastic cover). Over time, it was not unusual to have grime build up on top of the battery. In some cases, this crime could conduct electrical current when it came into contact with the cables, damaging the electrical system. We used to clean the corrosion and grime off by removing the battery and applying a baking soda paste. For some reason, this made the battery look like new again.
Okay, after I submitted this answer I read the ones about the igniting the gas. Clearly one of those deserves to be picked as the best answer, but what I said is correct.
2007-09-08 03:30:43 · answer #5 · answered by Bob 4 · 0⤊ 3⤋
Not sure. Doesn't make sense. The negative terminal post on the battery is already connected to ground, or grounded to the metal frame / engine block. I've never heard that.
Apparently... "hydrogen gas--which forms as a battery discharges and loses its fluid--is flammable, and a spark from the battery cables could, theoretically, set it off. We emphasize slight because the gas would have to be fairly dense around the battery for this to happen. This is unlikely unless the battery has been sitting for a long time and little or no air circulation has occurred in the area, but it is possible."
So I learned something too!
2007-09-08 03:26:25 · answer #6 · answered by Skip S 2 · 0⤊ 3⤋
because the last cable you connect there may be a spark. Batteries can emit a flammable gas. If the gas ignites, you have a fire under your hood. The idea is to keep the spark away from the battery.
Pos - Pos
Neg - Ground of dead car
In that order.
2007-09-08 03:26:37 · answer #7 · answered by T B 2 · 0⤊ 0⤋
A spark at the negative battery terminal could ignite explosive gases around the battery. It's like going to Las Vegas to gamble. Are you willing to take a chance connecting directly to the battery? In most cases you'll be ok. I would wear safety glasses so that any possible explosion disfigures my complexion but still allows me to see my burnt face in the mirror. Check the statistics on the number of people injured by battery explosions every year in this country.
2007-09-08 03:25:23 · answer #8 · answered by bobweb 7 · 2⤊ 1⤋
when a battery is charging it releases hydrogen gas. When you pull the negative side of the cable off the battery, arcing occurs. This arcing (sparks) can ignite the gas. Not Cool!
2007-09-08 03:29:22 · answer #9 · answered by Cody s 2 · 1⤊ 0⤋
Batteries produce explosive gases when charging or discharging. These gases can explode. It is not advisable to make the last connection to a battery post.
2007-09-08 03:32:58 · answer #10 · answered by gejandsons 5 · 0⤊ 0⤋