Edward

This, big time!

The real key to assessing a battery's ability to maintain its charge is measure its voltage with a reliable meter; and then do it again several days later to check for voltage drop.

A good battery should show at least 12.6v. (IIRC) in its static state, then no more than a .1v drop in around 5-7 days (mine in any of the family cars have stayed the same, or even higher perhaps depending on ambient temperature or when the car was last driven). But even if the car was not driven for, say, one week, a good battery will maintain greater than 12.6 static volts and not lose more than .1v in that 1-wk span. Longer than one week is why folks rightfully decide on using battery maintainers.

But continually using a maintainer without measuring voltage and all you're doing is charging the battery enough to start the car, but its ability to hold that charge is greatly diminished, which either leaves you with a dead battery elsewhere, or worse, a battery that just starts your car, leaving the owner with a false sense of security while that failing battery is now taxing your charging system. And we all know that alternators are far more costly than a battery.

Oh, and add me to the list of non-optima users! Had two in my life, and both died within only a few years; costly and frustrating! Compare that to conventional batteries in every car I and family members have owned over decades, and I can't recall any that have not lasted 5+ years! ...and just changed my 993 battery which was around 9 years old.

Edward

AOW162435

Just checked the 3-year-old Interstate in my 4Runner and found that I could add a small amount of distilled water to each cell in order to have it at the bottom of each fill tube. I will do the same for the Dung Beetle's Interstate tonight.

That is the first time I've ever opened a car battery. Pretty embarrassing considering all of the automotive work I've performed over the years.



Andreas

pp000830

Good to see you battery need not die hard, Bruce Willis would be proud!

IXLR8

An easy way for people to understand that concept Edward is to use the kitchen sink versus swimming pool example.

Voltage is an electrical pressure and if we had 12.6 inches of water (I am not saying 1 inch of water is equivalent to 1V) in both the sink and the pool, the pressure at a drain in each would be the same.

An electrical drain (your standby electrics ...alarm, etc) is equivalent to a drain in the sink and pool.

You can imagine that a drip of water every second would empty a sink far faster than a swimming pool.

And that is what battery capacity (Ah) is all about.

A battery that listed as 70 Ah when new may only be 40 Ah some years later and a given current drain will have the voltage decrease much faster when the capacity has diminished in the older battery...the reason for the quicker voltage drop.

Of course a faulty battery will have a faster self discharge as well.