Annoyed

Okay, so with the battery disconnected and fully charged sitting on around 12.8v, I can re-connect the battery and it will stay 12.8 for at least a day. I done a parasitic draw test on it a while ago and was only losing 30mA from what I remember (and was 50mA I think before I removed the A/C fuse).

So all good at this stage.

As soon as I turn the ignition on, my battery instantly drops down to about 12.3v and then keeps getting lower and lower until the battery dies. That takes about 2 minutes. I lose about 0.03v every second.

Random details/things:
- Battery is fine. Passed battery test.
- Everything was fine before I done an LS1 engine conversion.
- Removing all the fuses inside the cabin makes no difference.
- Dash lights and interior lights work except the right hand side door light and now my console light too.
- I have a bit of a headlight problem (they aren't on when I switch ignition on).
- Standard alarm removed.
- No A/C.
- It's not the fuel pump. Still happens when the fuel pump wiring is disconnected.
- No amp and cd player / radio in car. Antenna and speakers still there.
- I also have an alternator problem which seems to come on (buzz/hum) even when the engine and ignition is off. But I have this battery problem even with the alternator fully disconnected. When the alternator is connected it just drains the battery quicker.
- There is no problem with the charging system and battery when the engine is running.


That's about it. Would really appreciate any help. I've lost my mind over this and am close to driving it through a wall... then burning it... then further smashing it with a sledgehammer. Even took it to an auto elec / mechanic and he couldn't figure it out too after 5 weeks (along with a few other problems with my C4). More $$$ down the drain.

I'm gonna disconnect the starter motor, 02 sensors and antenna tomorrow... see if that does anything.

IAFF alumni

If your battery tests good, clean ALL of your grounds and give each a coating of dielectric grease.

wydopnthrtl

Sounds annoying..

2min to kill the battery is way off. You have either a suppliy or a draw problem. IMO.. I'd try a 100% known to be good battery before proceeding with investigations of draw. (I wouldn't assume the curent one to be ok.. even if its been "tested")

ANTI VENOM

2 minutes to kill a good battery should heat up the cables or burn something up. Then the problem will go away. hehaa

Annoyed

(Thanks for your quick replies & help guys)

I have, minus the grease.
I'm very sure it's not an earth-related problem.
I sanded and cleaned (to bare metal) all the earth points...
I have 2 cables from the engine to chassis + the thin original strap...
My batteries negative cable is only about 4-5 inches long + is thick (no homo lol)...

Annoyed

Agreed.

Poh.. if the problem ends up being the battery.. I'm throwing it through my windscreen.
My mate gave it to me and I've never liked it and have always been paranoid about it as it's only a 460CCA + if I remember correctly, he said it failed a battery test when he tested it and "use it for now just to see if the engine cranks over" when I was doing the conversion..... BUT, I had it checked and it read fine + as long as you don't turn the ignition on, it lasts for ages. As in; I could probably leave the battery connected for 3-4 weeks without it dying.

I so confusious

I'll try my old mans battery (600+CCA) in my C4 tomorrow.... if it's not raining.

Annoyed

Hmmmmm.. this is actually pretty helpful. Thanks.
I'm gonna touch all the cables with the ignition on.. see if any feel warm. Good thing it's cold-as in my garage and the motor will be cold too.

c4cruiser

Who did the battery test? Did you take it out and go to one of the chain auto parts stores? Was the battery fully charged at the time? A good auto repair shop would charge the battery to make sure it's at a full charge then perform a load test with the battery installed in the car.

The hum or buzz from the alternator is not right regardless if the engine is running or not. It may be a short inside the alternator or a bad regulator.

What voltage do you see with the engine running? Use a digital voltmeter at the battery terminals. My '87 shows 14.2 or 14.3 right after startup and slowly drops to around 13.7. If I turn on everything, lights, radio, even the defogger, voltage climbs back to about 14.3v. What's the voltage at the red wire at the alternator?

Once you turn the ignition switch to ON, the voltage should drop as the ignition switch will power up a number of things. A 12.3v reading is not that bad. On both my '87 and '02, I have left the ignition switch on for 15 minutes and I could easily start either engine.

Why such a short negative battery cable? IIRC, the OEM cable attaches to the back of the block and is about 20-24" long.

Annoyed

A popular franchise workshop tested my battery in front of me.
It was 95-100% charged right before I took it there.

Yeah, my auto.elec. told me there's an internal problem with the alternator. I was hoping that I connected the cables to it incorrectly somehow.

I see 14.4v with the engine running with all the acc. switched off.

Shorter the cables the better. Plus I don't know why any negative cable would be longer than a foot. There's earth points everywhere. My batt.earth is connected to the bolt under the "bonnet-stop-thingo".

383vett

I would change both the battery and he alternator and be done with it. Tests don't always diagnose problems.

Annoyed

Interesting.
But like I said, mine dies within a couple minutes.
Also, why should a battery drop down to 12.3-ish v when you turn ignition on? That's a pretty huge jump/difference. Like, what turns on? 4 little dash lights (big deal)?........ I can't think of anything else (in my situation.. with fuel pump disconnected....).


Hmm

12.65 is 100% charged
12.55 is 87.5%
12.45 is 75%
12.35 is 62.5%
12.25 is 50%

So.. going by that ^, my battery goes from fully charged, to 62% charged/full by turning my ignition on for a second.

1963SS

I'm betting that a new battery will fix the problem. If it was drawing enough to kill the battery that fast something would be smoking and/or ablaze. It's almost got to be a cell shorting out.

Annoyed

Yeah. I'll try to change my battery tomorrow.
I can't really afford to spend 200 or so $'s on getting my alternator repaired right now. Have the money but don't wanna be throwing it around on every problem of mine as I'll end up broke, quick-fast, as I'm unemployed.
The alternator isn't bothering me that much too.. as at least I know that that can be fixed/sorted very easily and that it doesn't draw as much power as the other problem.

Annoyed

Sounds good, but.... why doesn't my battery die when the ignition is off???
I'm thinking it's a wiring issue.
Like cable(s) incorrectly connected..
Faulty relay..
Antenna-related..
Immobilizer/alarm module/wiring/relay..
I don't know

I'll try a "new" battery asap and let you all know if it made a difference.

Annoyed

I disconnected the blower connector/plug on top of it & the starter motor. Then I checked the battery and it read 12.61 (which was down from the usual 12.8-12.9 after charging it).
I turned the key to ignition-on then quickly checked the battery again. It read 11.05. So it dropped a massive 1.56 in a second or so. The blower & starter are clearly not the problem.

(Btw, every time it goes from 12.8 to about 12.3 after turning the ignition on, the battery starts to charge itself back up after turning the ignition back off. So it would go from 12.8 to 12.3, then slowly go back up to around 12.74 after 8 or so minutes. But this time around, it went from 11.05 to 10.95 after a minute and just stayed there after turning the ignition back off. It couldn't "Wolverine itself".)

So this has me thinking the problem is the battery after-all.

I'll try to try out my dads battery in about an hour and let you all know if blah blah blah..

Cliff Harris

The negative battery cable should connect directly to the engine block. There is a bolt above the oil filter on the side of the block for that.

The starter draws FAR more current than anything else on the car (roughly 100 amps while cranking). You need a very good connection between the battery and the starter. The positive battery cable goes directly to the starter (actually to the solenoid, but same thing). The return is through the block. That's why the negative battery cable should connect to it.

Annoyed

(Edit: No, I haven't found the problem yet)

Looks like it's the battery.

I removed the battery and then remembered that I hadn't checked the water/acid level of 1 of the 6 "caps" because it was covered by a sticker + couldn't get a screwdriver on it because that diagonal bracket under the "bonnet-stop-thingo" was in the way.
I cut the sticker along the edge of the cap then removed the cap and noticed the water/acid was low so I filled it up to the indicator tab inside the hole.
Then while I was at it, I removed the crappy earth strap beside the battery and hooked up a nice fat cable from there to the back of my LS1 head.

So, here's the outcome..

Battery was on 12.93 after charging it earlier today.
I turned the ignition on for a second, then quickly measured the volts. It showed 12.8. I was like "wtf".
Then I turned the ignition on again and left it on.
Measured the battery again and was 12.61 and slowly dropping.

Then after writing that ^ down so I don't forget + waiting another minute, I measured the V's again and it was at 12.78 (ign.off).
I flicked the ignition on again for a few seconds, checked the battery and it showed 12.40.

Now the volts drop by about 0.008 every second. So that's over a 300% improvement.


So yeah, looks like I'll be spending another couple hundred dollars soon for a new battery.
I'm thinking of swapping my battery with my dads, since his engine is only a 3L and mine's a 5.7L..

Annoyed

Really? So connecting a 2-3 foot cable to the (hot) block from the battery negative terminal is better than a 4-5 inch cable to the (cold) chassis from the battery negative?
Does everyone agree with this??

Yes.
Btw, when you have the chance, can you tell me your before and after (you turn the ignition on) volts?

Thanks for your help + everyone elses.

Annoyed

I'm thinking something still has to be wrong for it to be losing power with the ignition on and just about everything disconnected.
There has to be something sucking the power out of the battery (ignition switch, some relay/module...)

Perhaps Cliff is correct about the neg.cable going to the block(?).

1963SS

The highest current draw on your electrical system is the starter. The starter needs a (+) and a (-) voltage. There are grounding straps on some engines that go from the block to the chassis and the battery is grounded to the chassis. No problem if the grounding strap is long enough. The engine block is isolated from the chassis by the rubber motor mounts and the rubber transmission mounts. The path to ground will be through the universal joints which is not a good thing. If the (-) battery cable goes to the block then there is no problem but if you want a shorter path for voltage then add the grounding strap to the length of the (-) cable to get a real idea of the length.

Straight to the block is a good idea but a grounding strap is still necessary. Best would be from the (-) battery to the block and the chassis.

Your battery is bad, feel free to change it. There are several types of internal shorts in a battery and without getting into all the specifics of each just feel sure that a bad cell can cause your problem.

That should tell you that the problem is internal to the battery, something like.....uh....a shorted cell. Use Google and check out the symptoms of a shorted cell on a lead acid battery. You're going to need a battery IMHO and all the testing in the world won't make your battery good again. A battery test done properly should pick this up easily.

Electricity is very, very logical and some things are just not making sense. If a battery went from fully charged to mostly discharged in that short of a time then it would be on fire. Has to be, always will. Good luck on your continued troubleshooting.