Inspired by
Tim's own investigation of his Paseo ... and his constant, incessant bugging me about how much power I thought it took from the battery and/or alternator to run my Pontiac Firefly (Geo Metro)...
Some good to know basic research. I was genuinely surprised how little power it takes to run the engine (no accessories on).
Voltage measured at the battery. Amps measured in a jury-rigged circuit with a multimeter inside the car. Volts x Amps = Watts.
To start the engine for the engine-on readings without blowing the 10A fuses in the multimeter, I roll started it.
Code:
Watts ... item
1.7 key @ ACC, ECU awake
17.8 key @ RUN, fuel pump finished priming
54 parking lights, dash lights high
59 brake lights
112 headlights, dash lights high
120 headlights high beam, dash lights high
36 key @ RUN (fuel pump running - priming)
6 radio low vol
18 radio high vol
96 radiator fan high
30 heater fan low speed (1)
49 heater fan 2
66 heater fan 3
81 heater fan high (4)
58 rear defrost
5 interior light
36 wipers low
53 wipers high
66 cigarette lighter
78 hazard lights (est)
42 horn (est.)
39 reverse lights
60 engine idling @ 880 RPM (alternator disconnected)
62 engine running @ 2500 RPM (no alt)
92 engine idling @ 880 RPM, alternator on (field current is high, topping up battery)
89 engine running @ 2500 RPM, alternator on - lower field current as battery voltage came up