Geo Metro Electrical Audit

[Noel]

'97 Geo with 1.0L

For those wondering just how much electric they use,

I hooked up an analog amp gauge with shunt. Easily to read to about .5 accuracy, good enough for this...

I hooked the gauge on the alternator feed wire going to the main fuse box where the 70 amp main fuse is.

With a fully charged battery, increasing rpm with load to ensure that alternator was able to put out what was being used:


DRL Disabled

Engine running, no lights or accessories on: 14.5 amps

Parking Lights: +4.5amps
Full Lights + 13amps (high beam no real difference)
Fan 1 +5.5
Fan 2 +7.5
Fan 3 +13.5
AC enable +5 for Condenser Fan

Turning on EVERYTHING I could, including rear defroster & Wipers, consumption was 64 amps. Not bad for a 55amp rated alternator. Battery connects on the fused side.

[metromizer]

Awesome report.

Chasing a different issue, I'd like to test mine with the engine and ignition switch OFF... my battery is dead within 4 days, and the belt squeals every morning, suggesting heavy load from a drained battery just from sitting overnight.

[Noel]

Will be doing another test soon, once warmed up once I find a digital meter to hook to my shunt. Cruising seems to be around 11amps, so looks like about 3 amps can be taken off the "just running" load.

[dcb]

Originally Posted by Noel

Engine running, no lights or accessories on: 14.5 amps

I'm guessing this 14.5 was mostly just recharging the battery immediately after a start.

[Daox]

Great post. I was looking for this kinda info just last week.

[Noel]

paid closer attention....11 when running and warmed up (and battery topped off)

[Johnny Mullet]

Originally Posted by metromizer

Awesome report.

Chasing a different issue, I'd like to test mine with the engine and ignition switch OFF... my battery is dead within 4 days, and the belt squeals every morning, suggesting heavy load from a drained battery just from sitting overnight.

Sounds like you have a draw or short. Easy test is to disconnect the + Positive terminal and hook a test light between them. Hook the ground from the test light to the battery disconnected positive post and the other end to the disconnected terminal. If the test light comes on somewhat bright, then you have a draw. Start pulling fuses one at a time until the test light dims out and then you know which circuit to test for the short

[bbjsw10]

Perfect timing on this was just figuring my AH for my alternator switch, I just installed today. Great post.!!

[bennelson]

Any idea how much power the spark plugs pull?

Of course this varies at different speeds, but if it was a known number, it could help calculate how far you could drive your car without an alternator.

[jenski]

You should check the current flowing to the alternator with the engine off or have the alternator tested. There are three diodes (diode trio) in the alternator to keep the current flowing back to the alternator when it is off. It also has to do with changing AC into DC, but that is another story.