Wha's your resistance?

[tashirosgt]

I don't know if such measurements mean anything, but next time you have the battery taken out of your AE92, measure the resistance between the negative battery cable and the positive battery cable. (Don't try such a measurement while the battery is hooked up !)

Mine:

1990 Corolla DX 4A-FE A/T key OFF accessories OFF 115 kilo ohms
1990 Corolla DX 4A-FE A/T key OFF headlight switch ON 45 kilo ohms

I find the reading on the meter drifts, but those are the averages.

[ericdude]

Not sure what the point of that measurement is, but unless you know for certain you meter
is using 12V to measure the resistance, you are probably reading resistance at at much lower
voltage that doesn't accurately gauge the behavior of the electrical system when the battery
is present. (Automotive electrical system responses are non linear, because of relay engagement
or microprocessor startup/shutdown.)

The proper way to do what you want, if I read you right, would be to use a DC current clamp
(best) or use the current setting on a multimeter wired in series with the positive terminal
of the battery. Beware that most multimeters will blow a fuse at 10 amps so measuring
the "everything off" trickle current is about all you can do without the current clamp.

You could get a very small (e.g. .01 ohm) resistor, wire it in series with the battery,
and then use the multimeter to measure the voltage drop across the resistor to calculate
current. You may need different resistors to span the range of starting the car vs. trickle
drain when everything is off--the resistor must be large enough the multimeter can accurately
read the voltage drop, yet small enough the the voltage drop is small compared with 12VDC.

[tashirosgt]

I merely want to see what other people get (with an ordinary multimeter) - just for the heck of it. I don't claim that it diagnoses anything.