Marine Battery FAQ Lifeline Battery manual
Marine Battery FAQs
What does AGM stand for?
It stands for Absorbed Glass Mat, the type of separator used in all Lifeline® AGM batteries.
What is the difference between AGM batteries and Gel batteries?
Both AGM and Gel batteries utilize oxygen recombination and pressure relief valves to minimize water
loss and allow maintenance-free operation. That is where the similarities end. AGM batteries have the
advantage of being mountable in any orientation without capacity loss, have lower internal impedance to
support high load currents, and have better capacity at low temperatures. Gel batteries must be mounted
upright to prevent air pockets from forming that will burn out the plates. They have inferior performance
at high discharge rates and low temperatures. Refer to Chapter 3 for further details.
Why should I choose Lifeline® AGM batteries?
Concorde has been supplying Lifeline® AGM batteries to the marine and recreational vehicle
marketplace for over 20 years, providing excellent performance, reliability and life. With this long history
and wide variety of successful applications, prospective customers are assured that Lifeline® AGM
batteries have proven themselves over and over again.
What depth of discharge should be used when sizing a battery?
To get the best cycle life, the average depth of discharge should be as low as possible. Concorde
recommends the average depth of discharge be no greater than 50% of the battery’s 20 hour rating.
What is the maximum number of batteries that can be connected in parallel?
In general, the number of batteries in parallel should be limited to four (4). It may be difficult to keep the
batteries in balance beyond this number, unless a special charging system is employed.
Can Lifeline® AGM batteries be installed in sealed containers?
NO! Do not install Lifeline® AGM batteries in a sealed box or enclosure. During charging, hydrogen gas
can be released and must be ventilated to prevent the possibility of ignition and/or explosion.
What is the best way to charge my battery?
Charge with a 3 stage charger that compensates the voltage setting as the battery temperature changes.
See Chapter 5 for further information.
What is the best charge voltage setting for outdoor applications if temperature sensing is not available?
NONE! Charging voltage varies widely depending on the battery’s temperature and there is no single
voltage that will work over a wide temperature range. Batteries will fail prematurely if this is attempted.
How can I tell if my battery is fully charged?
For a battery at room temperature, it can be considered fully charged when the charging current falls
below 0.5A per 100Ah of rated capacity. The open circuit voltage (after at least 4 hours of rest) will be
2.17 volts per cell or higher (13.0 volts for a 12-volt battery), regardless of the battery temperature.
How do I know when it is time to replace my battery?
Perform a capacity test as described in Chapter 5. Short duration load tests and impedance/conductance
measurements are not reliable to determine the actual capacity of a battery.
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