Battery Charging Problem

[JFP in PA]

If the battery is showing signs of not accepting a maintenance charge, pull the maintainer, fully charge the battery with a conventional charger, and then have it load tested (with a real load test unit, not what is described above). The load test is a pass/fail test; there is no ambiguity in the results. If it is good, put the car back on the maintainer; if it is bad, put in a new battery. Leaving the car with connected to the Ctek all winter with a dying battery is not good for the maintainer, and will not recover the battery................

[clickman]

Checked battery electrolyte level, and it was way low.

Filled it with distilled water and put it back on the CTEK. Will check it over the next 3 days to see if it switches from "charge" to "maintain".

I checked the electrolyte level last fall before putting the battery on the maintainer, and it was a bit low, and I topped it up then.

Is it normal to lose so much fluid in one driving season, or is there another problem, like the alternator?

(I was really dumb and had the battery connected up backwards last winter for a few minutes. No codes and the battery voltage checked ok afterwards, like the alternator was still charging ok.)

[JFP in PA]

Accelerated electrolyte consumption is usually the sign of an aging battery. As these things get older, the conversion of lead oxide to lead sulfate (production of current) and then back to lead oxide (on recharge) tends to be less complete, leading to the build up of sulfates on the plates, which increases the resistance inside the battery. Higher resistance leads to higher operating temps, and faster loss of electrolyte/water. While this is normal in the life of the unit, I’d keep and eye on it and periodically load test it……….

[paulv]

I have an '07 Box with the OEM battery, and starting in '09 I began measuring the battery cells (specific gravity and charge level) with a precision refractometer. In May '09 (~25K miles), the average cell measurement was 1.300. For Oct '10 (~41K miles), the average measurement has fallen to 1.265. For a good battery, each cell should be 1.260 or better. As others have said, four years looks like the limit for an OEM battery, and that's the direction my battery seems to be going!

Regards,
paul...

[JFP in PA]

Only problem with depending totally on specific gravities for determining when to swap out a battery is that other factors (internal resistance, cell weak bridging, etc.) will not be detected until the car strands you. A fifteen second load test will not only catch weak electrolyte (low SG), but will catch the other issues as well. The same load test unit can also test your alternator for diode response and voltage regulator activity, all at the same time, which is why load testing has become the standard test for battery replacement…………….

[paulv]

Originally Posted by JFP in PA

Only problem with depending totally on specific gravities for determining when to swap out a battery is that other factors (internal resistance, cell weak bridging, etc.) will not be detected until the car strands you. A fifteen second load test will not only catch weak electrolyte (low SG), but will catch the other issues as well. The same load test unit can also test your alternator for diode response and voltage regulator activity, all at the same time, which is why load testing has become the standard test for battery replacement…………….

Agree. Have you ever used any of those Midtronics battery testers? I used one on my wife's MB because the tech didn't know how to operate it (Tire store tech). They're a nice tester but being a DIY'er, it's beyond what my wallet can afford!!


Regards,
paul...

[extanker]

diode response ?