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mefly2 01-10-2014 11:51 PM

AGM Battery experience / help
 
We have two factory lifeline
agm batteries that are supplied with the solar option.

The problem is that they have consistently for the past 4-5 months dropped 10% per week on the gauge. The master switch is in store mode and we are getting some but not very much clear sunshine. The inside meter shows 30.1 as well today. We charged them fully after purchase and before off season storage ...doesn't seem like they can be trusted for boondocking.

Should the batts be self discharging at this higher rate? All I have been told is on are the smoke and carbon monoxide detectors.

Your experience with AGMs holding a charge in store mode???

lsbrodsky 01-11-2014 04:05 AM

30.1? Is that the percent charged gauge? The only thing I would trust is no load voltage after the charge has settled. If your setup is the same as mine, in "store" mode the only load is the propane detector, but the solar panels are still connected and will charge at 13.x volts. You need to look at battery voltage over a few consecutive days at a time when no charging has occurred for about an hour. Early evening, during the night, early morning. You should not see any real drop in voltage especially if you are charging during the day. A better test would be to measure battery voltage with the batteries disconnected completely over a couple of days. The self-discharge on a healthy AGM is almost nothing.
Larry

lewster 01-11-2014 06:10 AM

Quote:

Originally Posted by mefly2 (Post 1402041)
We have two factory lifeline
agm batteries that are supplied with the solar option.

The problem is that they have consistently for the past 4-5 months dropped 10% per week on the gauge. The master switch is in store mode and we are getting some but not very much clear sunshine. The inside meter shows 30.1 as well today. We charged them fully after purchase and before off season storage ...doesn't seem like they can be trusted for boondocking.

Should the batts be self discharging at this higher rate? All I have been told is on are the smoke and carbon monoxide detectors.

Your experience with AGMs holding a charge in store mode???

You surely have other issues, especially if you have solar. You could have:

• large parasitic drain on the batteries
• solar charger not working correctly
• solar monitor definitely not reading correctly (30.1?? :blink:)
• battery disconnect solenoid not working properly

There are many places to look for the cause of the voltage drop, but first you need accurate readings. Start by disconnecting the battery cables, use a multi meter to read the present voltage to establish a voltage base line and using an external 3-stage charger, bring the Lifelines to 13.2 VDC in a float mode.

After they are completely charged, leave them in a state of rest for a couple of days and re-measure the voltage with a multi-meter. Full charge is considered to be between 12.8 and 13.2 VDC. If they do not read at least 12.8, then they have been damaged and are not holding charge.

My first guess would be the Parallax single voltage converter that Airstream still insists on supplying. A continual charge of 13.6 or 13.8 VDC is NOT what Lifelines require, and will cause them to never receive a full bulk/absorption charge and a float charge that is too high, which will also cause them to start to sulfate. This condition can also be created by a solar charge controller that uses the wrong charging set points for your type of battery.

Try the test and let us know what you find.


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