My battery is experiencing a parasitic drain from an unknown source...

FYI, when using a multimeter, measuring voltage you can use the meter in series or parallel depending on what you are trying to read. Series would be reading a battery voltage at the terminals. Parallel would be putting one probe on the negative battery terminal and one on the frame looking for voltage drops.

Measuring amperage can only be done in series. So the meter has to be part of the circuit that you are measuring amperage through. ( there is also a clamp style meter but not relevant here )

Measuring resistance can be done in series or parallel but the circuit has to be dead.

 

I agree with everything you say but the part about the meter in series across the battery terminals seems a little strange. I could say it is in parallel with a circuit between the battery terminals having infinite resistance?

 

Standing voltage of a battery. Positive probe on the postive post, negative to negative. Can even be done while connected to a vehicle. It is a basic check done to indicate charge state.

 

Obviously but what is the meter in series with? "The Voltmeter is a measuring instrument used to find the voltage levels around an electrical circuit when connected in parallel with the part of the circuit being measured." quoted from this simple tutorial.

 

When the meter is connected to the battery it creates a series circuit. If the battery is connected to the vehicle then technically is is in parallel.

 

Kind of late to debate semantics but:
"For example, if we connect a voltmeter across the terminals of a fully-charged automobile battery, it will indicate 12.6 volts. That is there is a difference in potential of 12.6 volts between the batteries positive and negative terminals. Thus voltage, V is always measured across or in parallel with a circuit component."

 

Posted this on your other thread…

There appears to be a bullion concerning battery drain…

post #5037 on the KDMAX tune thread.

“I took my 2021 tacoma OR 4x4 in for the 6 month maintenance and they wanted to do a update because of battery drain from the overhead emergency assist ( I have not had battery drain). They said it would take another hour so I said I would get it next time. Should I let them do it? Love my KDMAX tune-------THANKS”

 

Have used this method with success quite a few times. Pull fuse, with meter on DC AMPs push leads into fuse holder lugs, wait a minute or two, observe reading, reinsert fuse. About as simple (idiot proof) as it gets.

 

So much surveillance crap on new vehicles that slurps the battery...
My 2021 sat for a month without starting it and it KILLED the battery. Toyota paid for the new battery after it was towed to the dealer...

 

Just a curiosity question. Would an amp probe work or is it not sensitive enough?

 

Is your truck completely bone stock

 

Had my wife's 2018 TLX in for battery problems (battery was replaced because it didn't pass load test).

Dealer said if your FOB is stored close to your car. The car will keep communicating with FOB and it's possible that adds unwanted battery load.

 

Are you talking about a clamp on ammeter? There are low current DC ones available and then there is the problem of separating the individual wires to clamp around.