AGM and GEL Batteries Technical Document
From DEKA Battery Plant in Lyon Station, PA

Posted 12-30-2004    

     When we purchased our 5 GP31 AGMs from the East Penn DEKA battery plant in 2002, they gave us this 16 page technical document. In this document we learned about charging voltages related to bank temperatures. Basically, as the temperature of the battery bank increases, the charging voltage should be decreased. Conversely, as the temperature of the battery bank decreases the voltage charges should be increased. We learned that it is important to have a temperature compensated battery charger and voltage regulator. We have a Xantrax Prosine 2.0 charger/inverter and a next step regulator by Ample Power.

     If you would like to read the 16 page PDF document then please click the link we have provided below. Once you have downloaded the PDF file you should save it on your own computer for printing and for future reference.

• Updated 2/18/2007 (links now to Deka PDF sources)
  • AGMs and GELs are called: Valve-Regulated Lead-Acid VRLA
  • Download the DEKA PDF document HERE
  • Visit the DEKA web site HERE
  • See our Battery Box commissioning photos HERE
     
• Updated 4/16/2008 Copied from the DEKA PDF
  • Does depth of discharge affect cycle life?
    Yes! The harder any battery has to work, the sooner it will fail.
  • Typical* VRLA Battery Cycling Ability
    vs. Depth of Discharge
     
  • Capacity Withdrawn and life cycles

  • %	Gel	AGM
    100%	450	150
    80%	600	200
    50%	1000	370
    25%	2100	925
    10%	5700	3100

    As you can see, the shallower the average discharge, the longer
    the life. This is why it’s important to size a battery system to
    deliver at least twice the average power required, to assure shallow
    discharges.
    
    Follow these tips for the longest life:
    • Avoid ultra-deep discharges.
    • Don’t leave a battery at a low stage of charge for an extended
    length of time. Charge a discharged battery as soon as possible.
    • Don’t cycle a battery at a low state of charge without regularly
    recharging fully.
    • Use the highest initial charging current available (up to 30%
    of the 20-hour capacity per hour) while staying within the
    proper temperature-compensated voltage range.

Sincerely,
Hayden & Radeen