Battery, Red Eye, Told to disregard

[olbob]

Checked my batteries recently, out of three (all the same, different years) two showed Red Eye, one Green, yet the voltage output was within a few 10ths. Checked several places and was basically told as long as voltage OK forget the color of the eye, that alot of the time they are not dependable. Batteries have 2 amp trickle chargers on them as cars are not winter driven. Anyone else have "Eye Trouble"
Bob

 

[DTNODYA]

OK, lets see if I understand what you're saying ... You have three batteries (presumably stored) and two of them have red showing in the little "your battery is good/bad" indicator. They should show green if they are good but if I were you, I'd take them to autozone (or another place that will load test them for free) and get them tested.

You can buy a little cheap ass syringe looking deal that has four different colored balls in it ... suck up a little of the water from the battery cells and the package tells you how to read the floating balls (from any auto parts store ... couple bucks) ...

The voltage, if you are reading it with a voltmeter, is not a good way to tell (unless it's reading 10 volts or something real low). Hope that helps some .. FWIW, if you've got chargers on em' all the time, I don't really see why they would be bad. Maybe they just need to be moved around a little to get the "ball rolling" or whatever.

 

[Mike97gt]

ignore the green/red indicator.. that thing is inaccurate so often I wonder why they bother with it.

 

[sgarlic]

Mine randomly went red one day too, but with no indication of low battery charge, or anything. I drove it around 15 miles or so, parked it in my garage, then the next morning it was green again. Now there's no color at all.

 

[san~man]

How old is the battery?

 

[LaserRed01GT]

If you are talking about maintenance free sealed wet cell batteries, the only way that you can test your batteries are with a multimeter and/or a load test. A lot of the maintenance free sealed batteries have a built in hydrometer that tells you the condition of the first and last cell (usually 1 and 6). This is why the hydrometer can indicate green but cells 2-5 can be bad or vice versa.

Measuring the voltage of the battery is not a very accurate way of measuring the condition of the battery, especially if the batteries were sitting on a charger and then you measured them right away. Just a variance of .5V can mean the difference of a 50% depleted battery. If you are doing that then all you are measuring is the surface charge. The surface charge must be removed before testing. To remove the surface charge immediately, you can place a load of 5% of the CCA on the battery for a few minutes, or you can just allow the battery to sit for a few hours off the charger before you measure the voltage.

You should get AT LEAST 12.5V. A good battery will normally show over 12.7V-12.9V. Sulfation can begin to occur at a resting charge of 12.4V or less. Anything under 11V and you can potentially have a shorted cell.

The best way though to determine the condition of a sealed battery is to perform a load test. A load of 50% of the CCA will be placed on the battery for 15 seconds. This has to be done when the battery is fully charged.

 

[Saleen4971]

the red/green etc. eye is used ONLY for measuring electrolyte level in the battery - to accurately test a battery it msut have at least a certain percent (i forget what exactly) - has no bearing on voltage

it is impossible for a battery to show over 12.6v - 6 cells that can produce a maximum of 2.1v each. anythign over 12.6v is called a "surface charge" and will throw off the test results. usually what you do is leave the headlights on fe a minute or so to remove the surface charge.

some higher end battery testers (like the GM testers and some snapon) will tell you to do that if it detects a surface charge