New Battery and now it’s dead

Sounds like your alternator is dead.

Possibly your alternator is not charging. Here's a simple test. Park your truck headed toward a wall or side of a building. Inside a garage is good too. Wait until dark. Now turn on the truck and then turn on the headlights. They should be illuminating the wall or building you're parked near. Notice the intensity of the lights. Now keep observing the head light intensity and turn off the truck. Is there a noticeable lessening of intensity? If no, then the alternator is bad. If yes, the alternator is doing something.

If a new battery went dead overnight I don't think it could be your alternator. It should last several days of normal driving with no charging activity at all. I think it more likely that something is draining your battery. In other words, something is staying on that shouldn't. Buy a 12 volt automotive test light (five bucks or so). Remove the negative cable from your battery. Connect your test lamp to the batter and to the dangling cable. If it glows brightly, something is drawing current that should not. If it glows very dimly, that's probably not the problem. Good luck. jor

I don't think putting a test lamp in series with the battery negative terminal is a good idea if you think there might be an electrical fault. It may just act as a fuse!

Get a Multimeter and use it on the highest Amps range. Reduce the range until you get a sensible reading.

This way you will 'quantify' your problem.

David

No, the lamp is in series - it will only pass it's normal operating current, and no more. It is a valid diagnostic tool for /some/ problems. But it only works well if you are looking for a hard short, when you clear it the lamp goes out or dims noticeably.

With a lightbulb indicator you don't have the resolution to see the milliamp level sneak loads that drain the battery over the course of a few days - for those you need to use a meter.

Regarding the original poster, first thing is to charge the battery overnight with a 110V charger, then see if the alternator is charging the battery and check for loads when everything is supposed to be off.

There are a few loads like the clock and computer memory that are always on, but anything over roughly 10 milliamps is too much.

-->--

Bruce L. Bergman wrote: snip

Exactly...

No. A 12v battery and a 12v lamp will not burn out each other even if you connect the lamp directly across the battery. Since that is equivalent to a dead short, connecting the lamp in series with the negative lead will be even less likely to have a problem. The lamp will limit the current thru the fault, as it will only allow its rated watts thru.

That works too. Unless your multimeter does not have a high enough amp range. And there are not many multimeters which will have an amp range high enough to place directly across the battery. Since a possible electrical fault by be exactly equivalent to that, a test lamp is safer.

sdb

Sylvan Butler wrote: snip

WHAT!?!...Christ, don't EVER put an ammeter across a car battery!...are you nuts?...what could ever be the purpose in doing that?...good lord!...

Exactly.

Which is precisely the reason why I responded to DavidB, who was worried about a testlamp if the car had a fault in the electrical system.

Since a fault might be a short, using an ammeter instead of a testlamp is identical to connecting the ammeter directly across the battery. Hence my conclusion: "a test lamp is safer."

sdb

Well, heck, there's no problem that the electrical system 'could possibly have' where it would matter if you connected a test lamp in series with the battery.

Not too damned 'likely' now, hell, if you had a hard short BEFORE you disconnected the battery then the current limiters would have blown or the battery would be dead as a nit so what's your worry in connecting an ammeter (in series) INSTEAD of a test light?...neither will make any difference at all.

Remember...you can safely connect a (proper voltage) test light 'across' a battery but NEVER connect an ammeter there.

That last sentence certainly is true, this can never do any harm at all.

I sure don't follow your other scenario...there's never any sense in connecting an AMMETER ACROSS any power supply...what could you possibly hope to accomplish by doing that?

Exactly.

Well, obviously when you begin troubleshooting, you replace the fuse and/or charge or replace the battery. At least, you had better.

There was never any other scenario. (Probably why it was hard to follow.)

That was never proposed. But in the worst case short, that is exactly what "series with the negative" would be.

A fire?

Welding?

sdb

Yeah like they said, check with one of those little test lamps on the negative side for a system current drain. That'll tell you right away if you have something draining your battery. Regarding the stalling vehicle ... my old corolla would not run with a weak (near dead) battery. Exact same symptoms you describe. Don't know why that is, but if the battery was near dead, the beast would stall and not run at all. Charged up the battery and all was fine. (I had alternator problem, not draining battery problem) Must have something to do with needing some juice to keep the engine "electrics" up and running. (excuse the farmer description ;)

To follow up on Jors good advice, hopefully your light will glow and tell you have a short. Now pull the fuses, one at a time. When the light goes out, you have found your faulty shorting circuit! Use your trusty troubleshooting skills to find you exact short. I had an old Ford with a cigarette lighter stuck in and cooking away! Now you can pull that fuse every night to prevent the drain until you find your propblem.

Keep us posted and good luck!

But note this will only work if the short is after the fuse - if it is and is bad enough the fuse whould have blown anyway.

Yes...the ignition system requires electrical power to run, so if the battery was almost dead and the alternator wasn't putting out any power then your engine would certainly stop. There'd be no ignition for one thing, and no fuel (electric fuel pump on most) Mind you modern engines also now have lots of electronic gadgets that also require power.

RIGHT. I meant OPEN circuit rather than SHORT circuit. Stereo amp on, light on, fuel pump on, etc. That is a good point about the fuse pulling troubleshooting being after the fuse box, though.

(Or did I mean closed circuit? Anyway, something is ON!)

Yes, you meant closed...most normal circuits are from the negative post of the battery to one side of each piece of equipment's 'on/off' switch, through the equipment, through it's fuse, through the battery's current limiter (just a big fuse) and back to the positive post of the battery. (electron theory), the 'hole theory'(?) - which makes no sense to me - has the current travelling the opposite way.