Help... Batteries are messing with me

[mandolindave]

OK ....Yeah. My two Optima AGM batts are 8 years old.( But I babied them )
Iota smart charger, never let them go below 12 volts, usually 12.2.
After a four hour drive ( fully charged ) they were at 12.2. I checked TV connecter and trailer umbilical cord- both good. Same thing next trip.
So I charged them for a few days, let them rest a few days, and plug in meter read 12.4. So, batteries done ...right. I checked them with same cheap plug in meter a few minutes ago and they read 12.6. What??? So I tested them with a dumb Fluke tester that only has increments of one volt. And it read 13 volts. I guess dumb fluke reads anything over 12.5 as 13 volts. Possibilities??

#1 Cheap plug in meter is wacky, Fluke meter is dumb
#2 Batts go up and down with day/night temps
#3 I need to get a good meter, and scientifically re test everything

What would you do....new batts are $400+

[mandolindave]

After charging....cheap plug in meter read 13.3 volts

[Bruce B]

8 Years is a long time for a battery, you are doing something right. I would borrow a real volt meter and verify the rest voltage. You might want to test the voltage while charging to be sure the charger is working too. I would wager that your batteries are failing.
Good luck!
Bruce

[mandolindave]

The batts recovered. Maybe I used some juice, thus the low reading, then after sitting, the batts recovered slightly

I did see a video on the Optima site, where the tech brought back a "dead" 20 year old red top. He also said ( but in good conscience , I will not recommend, because I am not an expert ) that you can desulferize and recondition an AGM Optima by dropping in on a soft lawn from waist height

DO NOT TRY THIS ON ANY BATTERY OTHER THAN AN AGM!!!!!!!!!!!!!!!!!!!

I also saw a video about a guy rejuvenating a totally dead batt using a
Bendini ( spelling error ? ) " school girl " motor. It was nick named a school girl motor because a young student used it as a science project.

DISCLAIMER: This is for your reading pleasure. It is NOT a suggestion

[Phoenix]

If you suspect your batteries are going bad, remove them from your Airstream and charge each one separately, overnight, with an automotive battery charger. Then, take them to your local autoparts store and have them load tested. Using this method will determine whether you are experiencing battery problems or whether something else is going on.

Also, batteries will show an artificial "float" voltage immediately after charging. This is a temporary higher voltage reading that will change after the battery has set for awhile with the charge voltage removed/off.

If your batteries individually read 12.0 volts or higher, and they seem to provide sufficient power, I would not be too concerned about the specific voltage measurements. However, a dead/shorted cell usually reads about 10.5 volts or less; and the battery probably won't recharge to 12+ volts. Sometimes a battery with a dead cell may temporarily show a higher voltage; but when load tested, the reading will immediately drop to an unacceptable level.

Not wishing to start a controversy, but I would never intentionally subject a battery to a severe shock. An internal dead short between cells can cause a battery to overheat and explode, spewing acid all over the place.

I have personally witnessed a special sealed battery (used in military equipment) outgas so violently when the positive and negative terminals were shorted together (on purpose), that it burst. Plus, before the minor explosion, the sparks from the electrical short ignited the escaping hydrogen gas that was venting out of the overflow, which turned the metal-cased battery into a spinning mass that skittered around on the floor, propelled by a blowtorch-like flaming jet that spewed acid all around the area.

While a spinning automotive/marine battery spraying flaming acid is probably unlikely, sparks, flames and a ruptured battery case that leaks sulfuric acid are not.

Also, while AGMs are more shock resistant than wet cell batteries, and less likely to leak under normal circumstances, an internal short would most likely produce similar results.

Just my opinion...

[mistral blue]

Originally Posted by Phoenix

I have personally witnessed a special sealed battery (used in military equipment) outgas so violently when the positive and negative terminals were shorted together (on purpose), that it burst. Plus, before the minor explosion, the sparks from the electrical short ignited the escaping hydrogen gas that was venting out of the overflow, which turned the metal-cased battery into a spinning mass that skittered around on the floor, propelled by a blowtorch-like flaming jet that spewed acid all around the area.

I would love to see a video of that! From a safe distance of course.

[ROBERT CROSS]

I took Lewsters advise when I was shopping for batteries several years ago, Optima's were considered along with several other brands.

Eight years is pretty darn good no matter the brand.

Bob