Team Camaro Tech banner

1 - 17 of 17 Posts

·
Registered
Joined
·
282 Posts
Discussion Starter #1
Hey everyone, I am having an issue with my battery going low on volts and not having enough power to start my car.

I have had the car for about 6 years now and last year started having this issue with the battery not being able to start the car. (Had to jump it if it sat for more than a few days). Don't remember really having any ongoing issues before this point, so I figured the battery was 5+ years old and just needed a new battery.

So last March I bought a new Optima Red Top (which came alittle low on Voltage from the store cause it was sitting on the shelf for 6 months). I have been working on a few car projects this summer so I put the new Battery on a battery tender until about a month ago when I finally got the car back on the road.

Now I am having the same issues with starting the car with this new battery. If the car sits for more than a week, there is not enough power to start the car. I hear one click and thats it. I pulled out my multimeter and the battery is currently at around 12.75 volts, but if I turn the ignition key to the ON position(car is not running) and test the voltage across the battery it is down to 12.4 which I assume is why there is not enough to start the car. Is this normal for the ignition on to cause a big voltage drop at the battery? Again the car was not running on this test, if the car is running with no accessories on it is around 13.3-13.5.

What is going on here? Did I just happen to get a faulty new battery and need to return it for another one or is there something else going on in the wiring? I haven't really made any changes to the wiring since I bought the car.

PS - One other thing that might or might not be related, is I have the 4 console gauges with the ammeter and the ammeter with the car running is consistently in the range of -20 discharge with no accessories on. If I turn the parking/headlights on it is practically pegged all the way to the left of the gauge at -40. I am not sure what is considered normal reading on this ammeter, but it doesn't look normal to be pegged at -40

Thanks for all of the help, I can't wait to get this figured out so I can go out to a cruise without jumper cables!!!
 

·
Premium Member
Joined
·
5,583 Posts
With 12.75 volts and 12.4 volts your car should start with no problem. Usually when you hit the key the battery voltage will go down to 9.5 to 10 volts.

I would double check the battery. A friend bought the optima and it only lasted a couple months.

Are you headlights bright and all other electrical works?

Make sure the starter is good. Can you jump it and it starts fine. Also check your positive and ground connections from the battery. Could be a loose connection.

If voltage is fine I would check the starter and all the wiring from the ignition switch to neutral safety switch to ( S ) terminal on the starter.
 

·
Registered
Joined
·
13,338 Posts
Check Mike says above.
Check volts.
With no motor running, and battery charged up... turn all the lights on, wipers, heater fan etc for about 30/ 40 seconds...
turn everything off, now check volts.
This is a quick 'storage' check..... weak or 'dud' batteries can be charged up, read a good voltage, even over night , but discharge very quick.

This is an optima lead acid battery right?
Not one of the other types for modern cars....
I can rem which way round it is , but put a lead acid battery in a new car or visa versa, modern battery in our old cars, they have different charging rates and stuff....1 way the battery doesnt get a full charge, the other the battery gets over charged...either way the battery life is shortened dramatically.

Your local work shop or battery shop should have an electronic scaaner type tool to test your battery...modern verson of the carbon rod, loading tools.

What is the batterys rating?

This may also be an on going issue...
Have u checked between a battery terminal and car connection, with everything off, if there is any currant draw?
If u have a memory radio, or alarm, even off these draw very small currents, enough to kill the charge over several weeks only....it is not uncommon to have a modern radio wired in incorrectly and drawing too much current.
This maybe indicative of your ampmeter reading slightly -ve.....

Another long term issue, is if the intial timing is high, the engine requires extra draw to turn over....this means extra heat in the starter, that becomes weaker over time , till eventually the mystical heat soak issue rears its head.

Before doing anything thu, connections, including the ign wires and alternator wires should all be cleaned up.
 

·
Premium Member
Joined
·
5,230 Posts
With 12.75 volts and 12.4 volts your car should start with no problem. Usually when you hit the key the battery voltage will go down to 9.5 to 10 volts.

I would double check the battery. A friend bought the optima and it only lasted a couple months.

Are you headlights bright and all other electrical works?

Make sure the starter is good. Can you jump it and it starts fine. Also check your positive and ground connections from the battery. Could be a loose connection.

If voltage is fine I would check the starter and all the wiring from the ignition switch to neutral safety switch to ( S ) terminal on the starter.
X2, I would also suggest your starter.
 

·
Super Moderator
Joined
·
32,603 Posts
I suggest swapping in a known good battery, maybe one from your daily driver, as the mechanical controlled charge system wasn't designed for the new design batteries.
The ammeter may be okay after the swap. Doesn't hurt to try, 50-50 chance.
 

·
Registered
Joined
·
282 Posts
Discussion Starter #6
Thanks guys for the reply.

I will check on some of this when i get home from work today and reply back. The headlights seem normally bright and other accessories seem to still work too.

When this problem happens, I can successfully jump start the car when I want to drive it. If I try to start the car within a few hours of taking it out on a drive, it will start fine on its own without a jump start. If it sits in my garage for like a week then I need to jump it to drive it again. Also, I have one of those twist knob battery disconnects on the neg. terminal, so I don't think it can be a drain while sitting because I disconnect it after each drive.

My battery connections are the side post GM ones and I do not have another side post battery on hand to try. I do have a booster battery pack to jump start with though and I have that charging right now, so I will try to jump it tonight and report back.
 

·
Retired
Joined
·
16,016 Posts
If you have never replaced the voltage regulator, hop down to parts store for Wells VR 715, about $10 , its solid state and will better regulate the elec. system too :)
 

·
Super Moderator
Joined
·
32,603 Posts
They have post adapters to go from one style to the other and back.
 

·
Registered
Joined
·
1,913 Posts
What I would do:

Clean battery cables at both ends

Measure voltage at battery, engine idling, no accessories on. Voltage between 13 and 15V? If not, bad alt or regulator.

Turn on headlights, voltage above 12.5V? If not, bad alt or regulator

Turn off engine and all accessories. Remove positive battery cable, insert an amp meter or a some 12V decent size bulb like a backup light. If the meter says >50MA or the bulb lights, something is draining the battery. Start pulling fuses and disconnecting things until it goes out (I'd start with the alternator).

If all that seems OK, reconnect the battery, turn on the headlights (engine not running) for 20 mins. Turn them off and try to start engine. If no crank, then replace battery.

If you get to this point, it's time to have the starter tested.
 

·
Registered
Joined
·
13,338 Posts
Remove positive battery cable, insert an amp meter or a some 12V decent size bulb like a backup light.
Be very causitous about using a light....the light draws current thru it, and everything else that maybe between it and ground.
If it is a bit of 'trickle' current electronics like a radio memory, alarm , gps....could cook it.
use a ampmeter.
 

·
Registered
Joined
·
282 Posts
Discussion Starter #11 (Edited)
Ok, so I got home from work and tested the voltage across the battery. It was 12.3. The lights etc. where still normally bright and I looked at the main connections and all were tight/clean. The car has now been sitting for 2 weeks now with the battery disconnected(no drains). I didn't have another battery to try but I do have a booster battery pak with built in cables to use for jump starting cars. I hooked up the booster battery pak and the engine turned right over! I then disconnected the battery pak and tested the voltage and it was now between 12.5 and 12.6. I then tried with just the Optima battery in the car without the battery pak and it turned over again, probably cause the booster pak gave it alittle juice.

So is it safe to assume that since the car turned over with jumping the battery with a booster pak that all the wiring/connections/switches in the car are good and I just got a faulty new battery from the store? At first I thought it was strange that my new battery was doing the same thing as the old one I got rid of but I am thinking by jumping it that it confirms the wiring is good and the battery is faulty.

thanks again for all the help, good thing this battery still has a warrenty!

PS and the battery is an Optima Red Top 75/25-925 Rated at 725 CCA and 910 CA.
 

·
Moderator
Joined
·
11,336 Posts
Sean, you might want to feel the battery cables for heat when it does not crank. If there is internal corrosion in the cables, they will be resistance and generate heat. If there is enough resistance, it would cause slow cranking. A better charged battery can overcome the resistance if it is not too bad.
 

·
Registered
Joined
·
282 Posts
Discussion Starter #13
Hey Kevin, thanks for poping in. When I just tested the cranking with and without the booster battery I disconnected the Optima battery in the car and while doing this the cables didn't feel warm to me. I will try checking this out again tomorrow.
 

·
Premium Member
Joined
·
4,806 Posts
As stated above, check for parasitic drain by using an ammeter.

Disconnect one battery terminal. Place the postive lead of the ammeter on the disconnected battery cable and the negative lead of the ammeter on the battery post. Do not turn the ignition key or try to crank the motor. You want to select the amps function on the ammeter and see if you are drawing current from your battery even while its off. If the draw is too high, it will discharge the battery enough so it won't have enough juice to crank the starter.
 

·
Registered
Joined
·
282 Posts
Discussion Starter #15
Brent, thanks for the reply,

I will check for drain but I am not sure if that is the problem here because as I stated above I have a twist knob battery disconnect on the neg. cable that I disconnect after each drive. So even though the car might sit for a week or two without driving, the battery is disconnected that whole time.
 

·
Premium Member
Joined
·
5,230 Posts
My Autozone battery is constantly at 12.7 when I check it. Not running of course. This battery is almost new. Just a point of reference.
 

·
Registered
Joined
·
273 Posts
Had the same issue in the spring. Was the battery. Ideally, you should read 12.6V with car not running. 2.1 volts per cell. You said you had 12.3, which might indicate a bad cell(s). 6 years is around the average lifesapn of a battery, although I've had batteries last 10 years and others 3.
 
1 - 17 of 17 Posts
Top