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Selecting a charger

Most deep cycle applications have some sort of charging system already installed for battery charging (e.g. solar panels, inverter, golf car charger, alternator). However, there are still systems with deep cycle batteries where an individual charger must be selected.

When changing between Flooded, AGM and GEL type batteries the existing charger may need to be changed and/or the voltage cutoffs reset. Chargers installed by most high quality original equipment manufacturers have selector switches built into their systems that allow the user to change between Flooded and GEL type batteries.

What follows will help in making a proper selection.

There are many types of chargers available today. They are usually rated by their voltage and there start rates or the rate in amperes that the charger will supply at the beginning of the charge cycle. When selecting a charger, the charge rate should be between 10% and 30% of the battery’s 20-hour AH capacity.

For example: a battery with a 20-hour capacity rating of 100 AH should use a charger rated between approximately 10 and 30 amps (for multiple battery charging use the AH rating of the entire bank to determine the charger rating required.

We recommend using a charger from one of the high quality charger manufacturers Discover® has approved. OEM chargers with Discover® approved charge curves prolong battery life and enhance performance. Alternatively we recommend using a 3-stage voltage compensating and temperature sensing charger. These chargers usually have three distinct charging stages: bulk, acceptance, and float. Some chargers that claim to have an equalize mode or stage should not be used on AGM or GEL batteries. Discover® approved chargers have Balance Charge modes included in there single cycle charge algorithms. Balance Charging is similar to an equalize charge but is performed using specific temperature adjusted current, voltage and time data.

Warning: Do not equalize charge GEL or AGM batteries.

Equalizing is an over voltage-over charge performed on flooded lead acid batteries after they have been fully charged. It helps to eliminate stratification and sulfation, two of many conditions that can reduce the overall performance and life of a flooded battery. Laboratory designed, specific to Discover®,  balance charge algorithms have been designed and are included in all Discover® recommended Industrial Commercial charges offered for sale wherever our Discover® VRLA products are sold. Visually the Balance Charging curve is similar to an flooded equalize charge curve in its finishing voltage, but it is strictly controlled to promote active material conversion and not to prevent acid stratification. Discover’s® Balance charging algorithms are highly recommended for batteries being installed in strings, larger batteries using taller plate groups and/or with batteries constantly being subjected to high rate deep discharges.

General Lead Acid Battery Description
General Lead Acid Battery Applications
General Lead Acid Battery Types
General Lead Acid Battery Chemistry
Discover® Sealed Valve Regulated Lead Acid Batteries
Discover® Deep Cycle AGM Battery
Discover®700 Series Dry Cell Battery
Discover® EV Traction Dry Cell Battery
General Benefits and Features of Discover Valve Regulated Lead Acid (VRLA) Technology
Sales Channels for Discover Battery Technologies
Things to question when making a battery buying decision
What to consider when buying a deep cycle battery
Information gathering before buying batteries
Calculating cost to own when purchasing batteries
Safety First
Safety and Productivity
When working with batteries
When handling battery acid
When installing or replacing batteries
When booster cables are used
Danger of exploding batteries
Warning and warning labels
Parallel connections for sophisticated users and installers
Parallel connections for unsophisticated users and installers
When charging batteries
Selecting a charger
General charging information for AGM and GEL batteries
GEL battery charging
AGM battery charging
Equalizing (Flooded batteries only)
Typical self-discharge of VRLA batteries at different temperatures
Typical self-discharge of high quality deep cycle flooded batteries at different temperatures
How much will a system cost for my 2000 square foot home?
Can I use all of my normal 120/240 VAC appliances?
What components do I need for a grid-tie system?
What components do I need for a complete solar system?
What type of solar module mounting structure should I use?
Where should I mount the solar modules and what direction should I face them?
Should I set my system’s battery bank up at 12, 24 or 48 VDC?
Should I wire my home for AC or DC loads?
Can I use PV to heat water or for space heating?
How do solar panels (cells) generate electricity?
Will solar work in my location?
Tables & Figures