|SEV Motorola alternator 30 Amp Volvo 122S|
|Wired Motorola alternator 30 Amp Volvo Amazon|
Instead of rebuilding the Motorola alternator I decided to get a new stronger one. Also because I didn't like the fact that the little red amp light in the dash was always glowing a bit when driving with the lights or fan switched on.
|Little red AMP light in dashboard Volvo 122S|
When I took out the old Motorola alternator I only disconnected the external voltage regulator instead of taking it out..keeping the original look.
|Disconnected Voltage regulator Volvo 122S 1969|
The new (SCG) Alternator has an internal voltage regulator so it's easy to connect.
|Installation instructions SCG 55 AMP alternator|
|New SCG alternator connections|
The black round part at the bottom is the voltage regulator
|New SCG alternator Volvo B20 engine|
|Factory test results 12V/55A SCG Alternator|
I measured the alternator pulley diameter and the waterpump pulley diameter in order to calculate pulley ratio.
Alternator pulley approx. 74 mm
Waterpump pulley approx. 128 mm
Pulley ratio in my B20 engine: 128/74 = 1.73
The alternator starts working at 1534 rpm --> engine ca. 887 rpm (1534/1.73 = 887)
The B20 engine in my 122S is idling around 900-950 rpm, according to the factory test results the AMP output at idling speed is around 31-35 A, which is already more then the max output of the old Motorola alternator.