Question: Battery Life in a C4 ?

[LastOfTheV8's]

I replaced the battery in my C4 seven months ago with a NUMAX 75-60 after the previous battery died. I fitted the NUMAX model because it was the only side terminal battery that I could source in the UK that would fit into my C4 (without modifying anything) and it seemed to provide just about enough CCA's to do the job- 550CCA. The voltage displayed when driving was a constant 14.3. I had to work abroad recently so I disconnected the battery before I left, for 5 weeks in total. I'm happy to report she started on the first turn of the key when I returned, but now the voltage varies constantly in the display while driving, varying from 15 to as low as 13, and on manoeuvres at idle she even drops to 11, causing the lights to dim briefly and the engine to shudder.. correct me if I am wrong but isn't this symptomatic of a dying battery ?!? Do I need to replace it again ? View attachment 21519

The previous battery acted in the same way in the weeks before it finally gave up on me, the voltage value in the display was skipping constantly... does anyone else's vette have similar symptoms?

What CCA's are required for cold starting in minus 5 degrees celsius?? -minus 23 fahrenheit ??

 

[Rogue]

If that is the correct battery for your car, it should last for years. I've had mine in the garage for 6-8 weeks at a time and she starts right up. You may want to check your Alternator and the connections. Lights should not dim at idle either.

Once you figure out the issue and fix it, you may want to consider a Battery "Tender". It is a device that you plug to your house current that keeps a your battery topped up when you are away and not driving the car regularly. It needs to be an "Automatic" battery tender that constantly monitors and adjusts the charge so that you can leave it plugged for long periods. A battery tender is not a substitute for a poorly running Alternator though. If you drive your car regularly, the correct type battery should never need replacement for several years (at least three, usually four to five years).

 

[vetteoz]

now the voltage varies constantly in the display while driving, varying from 15 to as low as 13, and on manoeuvres at idle she even drops to 11, causing the lights to dim briefly and the engine to shudder.. correct me if I am wrong but isn't this symptomatic of a dying battery ?

I would get Alt checked first, the volts display is a indication of what is coming out of the Alt ( when the engine is running) .The Alt should be able to run the engine without the battery even in the car ( not recommended)
I had a battery die on me when a long way from home , jumped started it and drove home fine just with Alt power
And yes the computer has a heart attack it voltage goes under a certain level

 

[G Winter]

This sounds like either a connection problem or a voltage regulator problem. Voltage regulator is built into the alternator. You had the battery disconnected so I would be suspect of the cable you had off. Also check the wires on the alternator especially the heavy 12 V constant .Either may have a bad end on it.
My experience has been that a bad battery will usually cause a high charging state.
If you get below 10 volts the ECM will very likely shut down the engine.

Glenn

 

[LastOfTheV8's]

I would get Alt checked first, the volts display is a indication of what is coming out of the Alt....
And yes the computer has a heart attack it voltage goes under a certain level

Thanks, that is sound advice, though it is slightly worrying too! I will have the alternator checked by my corvette guru

.. Lights should not dim at idle either...
Once you figure out the issue and fix it, you may want to consider a Battery "Tender"... A battery tender is not a substitute for a poorly running Alternator though. If you drive your car regularly, the correct type battery should never need replacement for several years (at least three, usually four to five years).

Thanks Rogue, a battery tender just went onto my christmas list! And remembering your point about the lights dimming; I noticed today that it has gotten worse.. pressing the brake while idling (either approaching lights or parking) is causing the lights and even the display to dim now too.. and the display flickers ever so slightly at all times, looking at the reflection of the headlights on the car in front they are actually flickering (slightly) all the time now -it definitely didn't do this before I had disconnected the battery... I suspect it is a slightly loose connector at one of the terminals.. or my alternator

This sounds like either a connection problem or a voltage regulator problem. Voltage regulator is built into the alternator. You had the battery disconnected so I would be suspect of the cable you had off. Also check the wires on the alternator especially the heavy 12 V constant .Either may have a bad end on it.
My experience has been that a bad battery will usually cause a high charging state.
If you get below 10 volts the ECM will very likely shut down the engine.

Glenn

All good advice guys, thank you... though I'm worried about an impending ECM heart attack now! Today when I got in, the digital voltage display read 10.8 -Not good!!! Tomorrow I will check the connections to the battery terminals..

 

[Rogue]

Well, I had my battery die on me slowly one time....it was doing what you were doing but not with engine running. It just died completely. When I replaced with good battery, everything went back to normal.

I think the ECM will just shut down your motor but not actually fry itself or self-destruct. The chip itself is easy enough to replace. I plan on replacing mine with a Super Chips upgrade that can take advantage of a freer flowing intake and exhaust.

 

[vetteoz]

a battery tender just went onto my christmas list!

Lead acid batteries are not designed for long term storage.They must be "worked" ; as in charged / discharged to maintain cond.If left sitting the plates sulphate up and once that happens you lose that area.
I lost a new battery in a year before I found that out because I was not running car often enough.
With the battery tender I have not had any problems

 

[John Robinson]

Back to the basic's

You removed the battery for storage. In order to do that you removed the positive and the negative cable. If the electrical system was working correctly when you put the car in storage then the only things that have changed are the connections for the cables. At this point I would be focusing on only the things that were disturbed. When you put the battery back in the car did you clean the corrosion off the battery terminals and the cable ends. Did you forget to tighten the negative cable tightly. What you describe sounds like an intermittent ground problem. Second thing to look for is to check and make sure while in storage you did not provide a home for a family of mice that ate your wires for a midnight snack and nest building. Again leading to a ground problem. Now we get to the interesting part are you sure that your gauge is not malfunctioning. I have used this trick to check the charging system on cars with only idiot lights instead of gages.

I am using a cigarette lighter plug in that has an on off switch and a fuse to connect to my meter being careful to use the right plus to plus connections. Now I can monitor what the charging system is doing. It is sometimes helpfull to have a Friend go with you to monitor the meter and make notes of any sudden changes. If you have any concerns about the alternator you can run wires from the alternator to the inside of the car and connect the meter to monitor the alternator under various conditions.

 

[LastOfTheV8's]

.. At this point I would be focusing on only the things that were disturbed. When you put the battery back in the car did you clean the corrosion off the battery terminals and the cable ends. Did you forget to tighten the negative cable tightly. What you describe sounds like an intermittent ground problem. Second thing to look for is to check and make sure while in storage you did not provide a home for a family of mice that ate your wires for a midnight snack and nest building. Again leading to a ground problem. Now we get to the interesting part are you sure that your gauge is not malfunctioning...

Thought provoking reply indeed! I disconnected the battery before I left because I was afraid of a possible parasitic drain rendering it dead by the time I returned.. was I wrong to do so ?
I guess the gauge could be malfunctioning, I will have the test you described carried out by way of diagnosis. Does anyone bother to use the analog gauges ? All of mine bar the oil pressure seem to read incorrect/excessive values, but since they have done it for as long as I have owned the car I pay no attention. The analog battery gauge always reads something like 16 I think, similar to another member's experience here.
Thanks for your help

 

[vetteoz]

I guess the gauge could be malfunctioning,

As the lights are going dim at low revs, it would appear that the gauge is reading consistant with what the battery is seeing

 

[vetzs]

At one time I was replacing the battery and sometimes the alternator about once a year. I just now replaced my battery after 7 years, it checked out fine with a load tester but I just got scared of it's age. I credit this to using a battery tender on the vehicle when I would park it for any length of time. I don't worry about battery's anymore, I have tenders on all of them when they sit.

 

[TedC]

At one time I was replacing the battery and sometimes the alternator about once a year. I just now replaced my battery after 7 years, it checked out fine with a load tester but I just got scared of it's age. I credit this to using a battery tender on the vehicle when I would park it for any length of time. I don't worry about battery's anymore, I have tenders on all of them when they sit.

I learned this lesson with my 1988 vette. Even starting the vette every month, I killed off a new battery over the winter. No problems since using a battery tender. I also spent $75 on a digital battery tester that tells me CCAs. Then you can monitor the drop in CCAs as the battery ages, and know when to replace the battery. Suggest cleaning the battery and alternator contacts, and pull the alternator for testing.

 

[Txbobcat]

I had a new exhaust put on my 92. While on the rack the battery went dead so we jumped it off. Leaving the drive I hit the gas pretty hard and it died again jumped again died again on takeoff so we finally replaced the battery. Allwas fixed but what I wanted to say was this. The car woudl misfire some at high rpms making me think it was time for a tune up. But after the new battery was installed it ran fine. Who would think the battery had enough to start the car but not enough power to keep it running correctly.

 

[John Robinson]

Old Saying

From the past we would always say a low speed miss valves. A high speed miss electrical.