Car Battery Charging Tips

Do not turn the charger on until both leads have been connected to the battery. Connect positive to positive and negative to negative. Do not reverse the connections as doing so may damage the charger and battery.
Slow-charging at 6 amps or less is best because it develops less heat inside the battery (which can damage cells and increase evaporation). A slow charging rate will also break up the sulfation on the battery plates more efficiently to bring the battery back up to full charge.
“Smart chargers” also work well because they automatically adjust the charge rate to the battery’s state of charge. Most start out with a charging rate of 15 amps or higher, then taper off the charging rate as the battery charge comes up.
Fast-charging a battery saves time but risks overheating and damaging the battery. If using a fast-charger, don’t use the highest setting. Use the “boost” setting only when cranking the engine.
Refer to the battery’s reserve capacity rating to determine charging times and rates. The charging rate (in amps) multiplied by the number of charging time hours should equal the reserve capacity of the battery. (Example: a dead battery with an reserve capacity rating of 72 will require charging at 6 amps for 12 hours.)

The Porsche 959 was another first to use a tire pressure monitoring system (TPMS) because it was equipped with the world’s first self-supporting run-flat tires made by Bridgestone. This TPMS setup was again used on the 928 for model years 1990 to 1994.

The early system used two sensors mounted 180 degrees apart in special holes in the valley of the wheel. The sensors looked like a stack of poker chips. A diaphragm inside the sensors connected to switches that were set to a reference pressure. The receiver was mounted on the knuckle and was an inductive coil that would pass current through the sensors. Depending on the position of the diaphragm and which switches were open or closed, the amount of current flowing through the receiver’s coil would change.