Charging – one of the most critical aspects of flooded lead-acid and VRLA battery care – is often misunderstood. By following proper charging techniques, you can optimize the performance and longevity of flooded lead-acid and VRLA (AGM and gel) batteries.
Be sure to fully charge these batteries after each use and periodically during storage to prevent damage. See your vehicle’s user’s guide and the instructions issued by your charger’s manufacturer.
Tips for Proper Charging
- Refer to your user’s guide for charging specifications for your battery.
- Verify that your charger voltage matches your battery pack voltage.
- Set the charger to the appropriate algorithm or profile for deep-cycle flooded, AGM, or gel batteries.
- Ensure tight connections between the charger and battery.
- Charge only in a well-ventilated area.
- Flooded Lead-Acid Batteries Only. Before charging, make sure the electrolyte covers the surface of the plates. If not, add water just to cover the plate’s surfaces.
- Do not interrupt a charge cycle.
- Never charge a frozen battery and avoid charging in temperatures above 120° F (49° C).
- Flooded Lead-Acid Batteries Only. Periodically equalize flooded lead-acid batteries. Equalization is an intentional overcharge given to a string of batteries. By fully charging all batteries and thoroughly mixing electrolyte, equalization reduces sulfation and stratification to extend battery life. NEVER equalize VRLA batteries unless instructed to do so by the manufacturer.
Charging times depend on how deeply the batteries have been discharged. VRLA batteries charge faster than flooded, and gel charge in about the same time as flooded, or a bit faster.