[KeithD]

Anyone reading my recent posts will see I'm having some...starting issues.
Good news is the starter is fine.
Bad news is I have something drawing power from the battery...killing it. Or at least draining enough juice I can't start her up.
My mechanic disconnected the alarm, and kept a meter (or something like that) on the battery for a day, and there doesn't seem to be any power loss. The alarm is (most probably) aftermarket, and put onwhen the car was new. I would assume a 19 year old alarm might be malfunctioning, and drawing power. I hope so....
Anything else I should look out for a battery drain?

 

[MK2Racer]

Use sandpaper on the battery posts, and cables and make sure they make a very good connection. Disconnect and sand/clean the battery to ground wire (runs from neg. cable on battery to the frame) If it dosent have a good connection at one or all of these points, the car wont have enough current to start, though voltage will still say around 12v. Also, I dont know if it is the same on the supra or not, but on my other car there is an engine to ground strap, and once it got disconnected I had some weird electrival problems.

 

[Dave A.]

Your mechanic was most likely monitoring the current draw from the battery with an ammeter. Do you know what the reading was on the meter?

 

[KeithD]

I think he said it was a steady 12 amps....not 100% positive though. he seemed to think it was fine.

 

[trdmkii]

12 amps seems pretty high of a draw for nothing attached. it should be very low....lemme check my little book here, ahah, ok the allowed level of amperage draw is .5 A (amps) or 500 mA (milliamps). So if it is still 12 amps then you have a really high draw.

 

[KeithD]

Sorry, I meant it's drawing 12 amps when running (generating 12 amps?)
I think he said with the alarm disconnected, it was drawing nothing, or virtually nothing.

 

[Dave A.]

Holy cow! Are you sure the mechanic is on the level! :roll: I hope he/she didn't disconnect the battery while the engine was running or attempt to start the engine with the ammeter connected in series with the battery cable! Never ever disconnect the battery with the engine running as that can cause some real havoc with the electrical system and electronics. Check for excessive current draw with everything Off and doors closed, doors locked, etc.. Disconnect the negative (-) terminal on the battery and connect an ammeter in series between the negative cable and the negative battery terminal and see how much load is being placed on the battery. .5 amps (500 milliamps) sounds a bit on the high side to me. Maybe 200-300 milliamps at most.

 

[trdmkii]

.5 amps (500 milliamps) sounds a bit on the high side to me. Maybe 200-300 milliamps at most.

hey dave i got that out of an automotive electrical book that i took in school last year, if it was .5 amps in our supras i'd be hunting it down but in some newer cars .5 amps is the limit, more computers more memory? i dunno i just went off the book.....