Mazda 2012 MX-5 Owner's Manual page 330

Keep all flames, including cigarettes, and sparks away from open battery cells:
Flames and sparks near open battery cells are dangerous. Hydrogen gas, produced
during normal battery operation, could ignite and cause the battery to explode. An
exploding battery can cause serious burns and injuries.
Do not jump-start a frozen battery or one with a low fluid level:
Jump-starting a frozen battery or one with a low fluid level is dangerous. It may
rupture or explode, causing serious injury.
Connect the negative cable to a good ground point away from the battery:
Connecting the end of the second jumper cable to the negative ( ) terminal of the
discharged battery is dangerous.
A spark could cause the gas around the battery to explode and injure someone.
Route the jumper cables away from parts that will be moving:
Connecting a jumper cable near or to moving parts (cooling fans, belts) is dangerous.
The cable could get caught when the engine starts and cause serious injury.
CAUTION
Use only a 12 V booster system. You can damage a 12 V starter, ignition system, and
other electrical parts beyond repair with a 24 V power supply (two 12 V batteries in
series or a 24 V motor generator set).
Connect cables in numerical order and disconnect in reverse order.
Jumper cables
Discharged battery
In Case of an Emergency
Emergency Starting
Booster battery
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