- 96RIVMANN wrote:
- For the heck of it I decided to pull out my 76month 7 year AC Delco battery from my '96. I have owned the car since July of '03 and I have put 105K on it. I put the battery on the bench, raised one end about two inches and pushed a piece of hose over the vent and began filling it with a big syringe. It took 12.5 oz before it was full. Washed it down in the driveway and stuck it back in. Not sure how to read the date code on the battery but it is at least 8 years old and going strong. I think I caught it in time because that seems to be quite a bit of distilled water to have to add. Anyway, just giving everyone a heads up if you were thinking of doing this I say go for it.
Interesting - but for others reading this note please note the following:
- the healthy battery puts out about 2.1 volts per cell, open circuit. So the first think you wanna know is, is your battery healthy? A quick first step to ascertain that is to disconnect the negative terminal wire, then measure with a voltmeter. You will see approximately 12.6 volts in a fully charged battery. As the battery ages, the fully charged voltage declines a little but don't wig out (yet) if it's like 12.2 or 12.4 volts.
- Reconnect the negative wire, then turn on all the lights (interior and exterior) and measure voltage again. This puts a few amps draw on the battery. Measure voltage. If the voltage drops a lot (my guess would be below 11.75 or so) your battery is weakening. Make a note of that voltage then turn off the lights.
- If your voltages remain above the thresholds, I would not mess with that battery at all. The OE batteries are a lead-calcium formulation and are intended to last a very long time. 10-12 years is no surprise.
- The battery is "done" if it puts out insufficient cold cranking amps. I think the threshold for our cars is 450 CCAs. Unless you have a tester (LINK) that will put that kind of load on the thing you will need to go to an auto parts store or repair shop for testing. Many if not most of the places that sell car batteries test them for free. And if you do want to buy your own check on Amazon or Google Shopping they are about 1/2 to 2/3 the price shown on eBay.
- if you add water to the battery somehow be absolutely sure it's distilled
. If you add water with any mineral content, including what is sold as "drinking" water in bottles, you will add minerals to the electrolyte that will (likely) short out the cells.