Dead AGM Battery

ChessieMike

Hello all! On June 22, I purchased a brand new 12-volt AGM deep cycle dual marine battery for my 2015 T@B. Last weekend, we decided to go camping and I noticed the battery was completely dead. I hooked up a meter and it showed zero volts. I was quite surprised because I pulled the battery fuse as recommended by my dealer. That last time this battery was hooked up to "shore power" was during a three-day camping trip about a month ago. The battery charged last weekend, but I noticed it was dead again today. 
Do I have a larger issue with the trailer or did I simply get a bad battery?  Here is the battery I purchased: https://www.batteriesplus.com/battery/rv/deep-cycle/12/sli24agmdpm
  

Sharon_is_SAM

How long did you charge it?  How did you charge it - via the converter or a separate charger?   Was it fully charged before storage?  I know that a partially discharged battery will not hold it's charge as well and given that you only have a 75 amphr capacity, it would not take much to drop into the depleted range.  

Verna

Try this from our category of "User Manuals/PDF Files..."

http://tab-rv.vanillaforums.com/discussion/1101/how-to-revive-a-dead-agm-battery-that-wont-take-a-charge#latest

ScottG

0V is pretty peculiar, even for a "dead" battery.

Are you checking it right at the battery terminals? Does the voltage come up when you charge it (even if the charge doesn't hold)?

If the battery charges up then discharges that quickly/deeply when it is fully disconnected, that points to a problem with the battery itself.

ChessieMike

SAM said:

"How long did you charge it?  How did you charge it - via the converter or a separate charger?   Was it fully charged before storage?  I know that a partially discharged battery will not hold it's charge as well and given that you only have a 75 amphr capacity, it would not take much to drop into the depleted range."

Hi Sam, It would have charged for about three days when I was camping via the converter. I am not sure if it was fully charged before storage.  I went ahead and charged the battery with a regular battery charger. It only took about two hours to bring it to a full charge. I will see if it holds a charge for the next several days. 

Sharon_is_SAM

Check the battery specs for recommended charging voltage.  Not sure if a regular charger is ideal.  After you charge it for a few days, check the voltage.  You may consider having a shop check it, too.

wizard1880

Wow, if the battery is reading 0v truly, it has a dead cell.  Try your voltmeter on your vehicle's battery to confirm its working, then test the AGM again.  0v?  Take it back to the store and swap out for a new one.

While it's rare, batteries will short out internally or break a contact inside, usually when either new (manufacturing defect) or very old (sulfation buildup shorting a cell).

I hope you get it all sorted out soon...  Primo camping time is not the time for these types of failure!