98 Sebring Conv.-- Draw on battery.

Ok, here's one for any of you Experts out there.

Battery started dying weeks ago, decided to replace it. Local auto parts
checked alternator in car, charging fine. Noticed big spark when connecting
neg. terminal, so connected 12 Volt test light between neg. and pos.
terminal. Very bright light, meaning big draw. Pulled ALL fuses one at a
time, inside engine compartment and passenger compartment. No difference in
brightness of light. Then pulled fuses on 2nd aftermarket alarm system.
(Don't ask me why this car has two alarms.) No difference in brightness.

I'm thinking it could be bad diodes in alternator? Havent' checked that yet.
Problem is I cannot get my hand down to the connector to disconnect
alternator to check for draw, also don't have the tools right now to take
off alternator.
Anybody know another way to check if alternator is causing a draw?

Another possibility is the draw will reduce after all the systems go to
sleep, and my old battery was just to old to handle the initial draw when
the car turns off.
How do I check for this with an ammeter while the battery cables are
connected?

Thanks.

 

You could look at the voltage with the engine running with an
oscilloscope, but I'm guessing you don't have one if you don't have the
tools to remove the alternator. (not a slam, just a statement of fact.)
Other than that, look for the other end of the wire coming from the
alternator, possibly on the starter solenoid if you have one? Then you
could disconnect there and check for current with your test light.

You don't. Ammeters are used in series so the battery cable needs to be
disconnected. Do you have some test leads with alligator clips?

good luck,

nate

 

Actually nate is not QUITE 100% right.
You need a "clip on" ammeter. They generally come in several ranges
from automotive tool suppliers. The 200 amp unit is used to test
starter draw, the 60 amp to check charging system output, and there
are smaller ones, around 10 amps, for checking loads.

Otherwize, there are "shunt" ammeters that go on the battery post and
the cable connects to it. With the heavy shunt in place it reads heavy
currents - like starting. Open the main switch, taking the heavy shunt
out of the circuit, and it read on the low range for charging system
tests.. On some you can also take out a smaller shunt, making it read
much lower currents for troubleshooting things like "phantom loads"