battery issues

[forzasteve]

Some of my thoughts on this ...

As someone pointed out, having the car sit for a few weeks without driving should not cause the battery to drain to the point where the car will not start ... unless there is an unusually high battery drain. If you experience problems with a newer car and a low battery, it is most likely you have a bad battery.

Someone else correctly stated that if the battery does drain down too low, then the battery is effectively compromised and it will not recharge to its initial capacity. Surprising to many people, is that once the battery is placed into service, if it discharges to about 80% to 85% of capacity, that is enough to compromise the battery capacity and battery life.

All modern cars will drain the battery when ignition is turned off. The drain is not much. Should not be more than 25mA to 40mA. This will drain a good battery in a few months. In addition, a battery will self-discharge at about 10% per month just sitting.

When you purchase a new battery, always make sure a battery is no more than 4 to 6 months old. Although a new battery may be say 4 months old, it will have drained down to about 70% of initial capacity ... but since it has not been placed into service, this is not too much of problem. Certainly, you should make sure it is no older than 6 months when you purchase it.

A battery tender is an excellent investment if you frequently leave your car for more than 7 to 10 days at a stretch without starting. A good battery tender will not overcharge your battery like the old trickle chargers used to do.

Most new batteries are sealed, but common flooded cell batteries will lose electrolyte over time. There is a school of thought that even so-called sealed batteries should be inspected for electrolyte level.

AGM batteries are not only sealed, but the electrolyte is distributed in a mat between the plates in the cells. Hence the term, AGM = Absorbed Glass Mat. These batteries have less electrolyte and are constructed so the free hydrogen gas given off during charge cycles is re-absorbed into the electrolyte. These batteries do not require venting and you never have to be concerned inspecting the electrolyte level. They are more expensive than common flooded-cell type batteries, but generally deliver superior performance and life span. They are less likely to leak if tipped over. I would not stake my life on that, so keep them upright.

To summarize some recommendations:

• When you replace your battery, strongly consider an AGM battery. Generally, it's worth the extra money to get the superior performance and life span.
• If your battery location is inside the car ... for example, modern Camaro's frequently have the battery in a well inside the rear luggage compartment ... you have even more incentive to use an AGM battery as the risk of explosion due to free hydrogen gas collecting in small space is minimized. If your battery in your Camaro is not an AGM type, it is VERY IMPORTANT to make sure it is vented to the outside.
• Do not put a marine battery in your car. Just because a marine battery is a deep-discharge type battery, it will not deliver the required performance in a motor car.
• If you do not start your car regularly and drive it long enough to recharge the battery, get a battery tender.
• If you do a lot of driving with frequent starting and stopping the engine, this puts a severe demand on your battery ... get an AGM battery as they tolerate this better than common flooded-cell batteries.

I authored a paper and posted on this forum. You can read more here
http://www.camaro5.com/forums/showthread.php?t=431971

Best regards,

Steve

[vatechguy3]

Took the car back to the dealer after a week of driving it normally.

They can find nothing wrong of course, including the battery.

They are keeping it over the weekend and will evaluate it again the first of next week.

Thoughts?
What should i have them test or try?

Thanks
Tony

[forzasteve]

Originally Posted by vatechguy3

Took the car back to the dealer after a week of driving it normally.

They can find nothing wrong of course, including the battery.

They are keeping it over the weekend and will evaluate it again the first of next week.

Thoughts?
What should i have them test or try?

Thanks
Tony

If the battery continues to drain down rapidly when car is off, then it would be good idea to determine what the current draw is when car is off. If the current draw exceeds 25mA to 35mA, then you need to find out why. If the current draw is in that range or less, and the battery continues to fail, then you have a bad battery.

Steve

[vatechguy3]

another dead battery this morning. this time is sat for 7 days.

will be calling the service manager at the dealership. not going through the service writer.

also gonna start looking into the lemon law.

tony

[sigmundreese]

Damn that sucks man, yeah I'd be pretty pissed off right about now.

[nvydvr]

The problem I ran into with one was when they claimed to do a load test and to check for any drains on th battery. They just hooked their computer to the battery for the test and you have to put the meter in series with the system! In other words the battery has to be disconnected and the meter place in series with the circuit... That seems to = too much work for some dealerships.

[68rssscamaro]

Originally Posted by forzasteve

If the battery continues to drain down rapidly when car is off, then it would be good idea to determine what the current draw is when car is off. If the current draw exceeds 25mA to 35mA, then you need to find out why. If the current draw is in that range or less, and the battery continues to fail, then you have a bad battery.

Steve

I would agree with Steve here. Have the dealer show you the sequence of the draw test procedure. There maybe a draw when they do not test it and when the car is off, so the draw test should be done periodically when the dealer has it. If it were me I would go somewhere else, it's like going to the doctor-get a 2nd opinion.

It sucks, but they should be able to find this problem

[68rssscamaro]

Originally Posted by nvydvr

The problem I ran into with one was when they claimed to do a load test and to check for any drains on th battery. They just hooked their computer to the battery for the test and you have to put the meter in series with the system! In other words the battery has to be disconnected and the meter place in series with the circuit... That seems to = too much work for some dealerships.

+1

[roh]

Originally Posted by nvydvr

The problem I ran into with one was when they claimed to do a load test and to check for any drains on th battery. They just hooked their computer to the battery for the test and you have to put the meter in series with the system! In other words the battery has to be disconnected and the meter place in series with the circuit... That seems to = too much work for some dealerships.

Not necessarily

http://en-us.fluke.com/products/all-...html#techspecs

I'd venture to guess that few places put a meter in series anymore. Much easier to measure it inductively.

[nvydvr]

Originally Posted by roh

Not necessarily

http://en-us.fluke.com/products/all-...html#techspecs

I'd venture to guess that few places put a meter in series anymore. Much easier to measure it inductively.

This is true, but do the dealerships have clamp on ammeters with oscilloscopes to read. This is above my knowledge, but are they as accurate... I don't know how much I'd trust the dealership with this, they're not electrical engineers

[roh]

Originally Posted by nvydvr

This is true, but do the dealerships have clamp on ammeters with oscilloscopes to read. This is above my knowledge, but are they as accurate... I don't know how much I'd trust the dealership with this, they're not electrical engineers

While the one I referenced works with a scope, many work with a basic mulitmeter. They are very accurate. The one that a dealership would have (likely as required by GM) would be already integrated with their starting/charging sys/battery tester. It does not take an electrical engineer to measure draw, however when that does not immediatly uncover the problem, things can get a little more complicated.

I'm as cynical as the next guy when it comes to people who work on my cars. the only point I'm trying to make is that you don't have an argument that they didn't put a meter in series, so better to take the angle that they didn't fix your problem, than try to tell them that they didnt do what they said they did.

[nvydvr]

Originally Posted by roh

While the one I referenced works with a scope, many work with a basic mulitmeter. They are very accurate. The one that a dealership would have (likely as required by GM) would be already integrated with their starting/charging sys/battery tester. It does not take an electrical engineer to measure draw, however when that does not immediatly uncover the problem, things can get a little more complicated.

I'm as cynical as the next guy when it comes to people who work on my cars. the only point I'm trying to make is that you don't have an argument that they didn't put a meter in series, so better to take the angle that they didn't fix your problem, than try to tell them that they didnt do what they said they did.

Uhm yea sure... You win... I'm gone.

[roh]

Wow....sorry.
Didn't mean to hurt any feelings here.

Just trying to help keep any members from coming off as a dufus at the dealership.

[forzasteve]

There are two factors which are most common for early battery failures:

1. The battery is faulty. This can be a bad cell or the battery has sat on a shelf too long before being installed in the car and other factors which can lead to early battery failures. This can be determined by placed a prescribed load (are relatively high load) and measuring how long it takes the battery to draw down to something like 10 volts. Most shops have a tester that will quickly determine if the battery is faulty.
2. There is excessive current draw on the battery when the ignition is turned off. The normal current draw that one would expect is about 25mA or so. Give or take. Generally if the current draw is more than say 75mA ... you have a problem. You are not likely to be able to accurately determine this low current draw with a clamp-on ammeter. They are not that accurate, particularly at low current situations. There may be some that are, but by an large, they are not. To measure this current drain when the ignition is off requires that you put a digital ammeter in series with the battery. But the problem comes that you cannot just do that from the git go, because you have to wait 15 to 20 minutes after shutting off the ignition to do that. And, the catch 22 ... when you disconnect the battery to put the ammeter in series you have to wait another 15 to 20 minutes because the act of disconnect will reset the ECU and you have to start over. The way to do this is place the ammeter in series before disconnecting the battery, then wait 15 to 20 minutes before disconnecting the battery.

Here is paper I wrote on this subject ...

http://www.camaro5.com/forums/showpo...07&postcount=1


Steve