A fully charged battery can discharge hundreds of amps through a spark, producing a current similar to that of a welding arc; like a massive amount of water that is not under great pressure, this can still kill. Jumper cables are universally color-coded red for positive and black for negative. Reversing these polarities will almost certainly result in a massive spark that can cause severe burn injuries.
The complex electronic systems of modern vehicles can also be destroyed by reversed polarity. Always connect both ends of the red cable first; this prevents accidental sparking to the body of either car as the second cable is connected. When batteries charge, they give off hydrogen gas, and a discharged battery connected to another vehicle via jumper cables is charging.
Hydrogen is extremely explosive when mixed with combustion air, and this dangerous mix typically occurs close to the charging battery. Causing a battery to explode with a spark from jumper cables can create flying shards of plastic that can easily blind anyone standing nearby.
Aside from the obvious dangers of being near an explosion, remember the electrolyte in lead-acid batteries contains sulfuric acid, which aggressively attacks human tissue.
When a battery explodes, it can shower nearby people with acid. Some hybrid vehicles carry a voltage much higher than anything delivered by regular utility mains.
If you have never turned a car key to hear that sad click-click-click of a starter without enough juice to power up the engine, then lucky you. Like changing a tire , knowing how to jump-start a car is a critical skill that every well-prepared motorist must master.
A word of warning: Jumper cables, when live, can be dangerous, so exercise caution when attempting to jump-start a vehicle. You will need a pair of jumper cables and a vehicle with a functional battery to which you can connect. Note that if your cables are too short to connect the two batteries, you can connect two sets of jumper cables to give yourself more length.
Just remember that your car battery may be dead again the next time you try it if the battery was worn down by age or defect; consider driving right to an auto maintenance shop to get it tested and, if need be, replaced. Once jumper cables are connected to a battery, consider them live; touching two of the clips together or letting them touch the ground may cause a shower of dangerous sparks and can also be bad for the battery.
Never try to jump-start a battery that is frozen; if the ambient temperature is below freezing and your dead vehicle was parked outside, you need to warm the battery with some sort of heater or call for professional assistance.
Also avoid connecting jumper cables to dirty battery terminals as this may prohibit a safe and complete connection. Use a brush with stuff bristles to clean a dirty terminal.
0コメント