Bosch’s heavy-duty Long Haul Extreme alternators are engineered to provide superior power output on the road and at idle, with advanced electronics and a design to faciliate trouble-free operation, increased battery life and added fuel savings. The alternators (AL9920LL, AL9921LL and AL9922LL) come in 170- and 200-amp versions, producing respectively 170 and 200 amps at 6,000 alternator rpm operating output and 120 and 122 amps at 2,000 alternator rpm. The Long Haul’s high charge rate at lower engine rpm helps prolong battery life by reducing deep cycling, while dual internal cooling fans optimized for maximum airflow help maintain an even temperature under all operating conditions.
The alternator’s bearing technology and a “brush” compound help facilitate longer life, as does built-in thermal protection designed to allow the alternator to sense extremely high underhood temperatures and to continue to operate at a reduced voltage output until the engine compartment reaches normal operating temperature below 257 degrees Fahrenheit (125 degrees Celsius), at which point the voltage output returns to normal.
