Valve Regulated Lead Acid (VRLA) batteries are widely used in a number of different applications, from mobility scooters and powered wheelchairs through to communications sites.
When you install a Gel or AGM type battery for any application, you need to ensure you’re using the correct size battery charger for the technology and size of your battery. If your battery is not fully charged, it cannot operate at its peak performance.
So how do you determine which battery charger you should use?
In this blog, the team at Valen take you through the steps of calculating what size charger you need for your VRLA battery.
First, let’s take a quick look at battery charger settings
All VRLA battery chargers have 2 settings – boost and float.
When the charger is boost charging, it is pushing as much capacity into the battery as possible. Once boost charging is completed, the charger light will go to green indicating that the charge has been completed. The charger will then switch into float charge. This means it will trickle charge the battery up to 100%.
In order to get full capacity out of your battery, it is crucial you allow the battery to stay on float charge for several hours after the charger light turns to green.
What information do I need to know?
To calculate what size VRLA battery charger you need, the first step is to make sure you know:
- Battery amp hour (total capacity)
- Battery voltage (total voltage)
- How fast you need to charge your battery (in hours)
- VRLA vattery technology type (AGM or Gel)
How do I calculate what size charger I need?
Once you’ve confirmed the above information, follow the below calculation steps:
- Charging time required (Charging Hours), divided by two = the Charging Time. Note: we divide this in half to give the battery enough time to float charge and come up to full capacity
- Battery Capacity (Ah), divided by the Charging Time = the Charger Capacity (A)
- Charger Size = Battery Voltage (Voltage of the charger) and the Charger Capacity (A) calculated above.
For example, Bob has a 24V100Ah battery system and wants it to be charged within 12 hours. Let’s take a look at how he would calculate his required charger size using the steps above.
- 12 hours (Charging Hours) / 2 = 6 hours (Charging Time)
- 100Ah (Battery Capacity) / 6 hours (Charging Time) = 17A (16.677 rounded) (Charger Capacity)
- Therefore, Bob needs a 24V17A VRLA battery charger
TOP TIP - a battery charger is too large for the battery if it is more than 25% of the battery capacity.
What can happen if I use the wrong size VRLA battery charger?
Using the incorrect sized VRLA battery charger can impact on the performance of your battery as well as reduce its life expectancy.
You have a greater chance of purchasing the incorrect technology specified battery charger than calculating the wrong size. Every battery charger is designed for a specific battery technology. Just as Gel battery chargers are designed for Gel batteries, Lithium Phosphate battery chargers are designed for Lithium Phosphate batteries.
So always ensure you are using the correct technologically specified battery charger for your battery before charging.
We recommend purchasing your VRLA batteries and charger from the same supplier/manufacturer to reduce the risk of using the incorrect battery charger.
Also, let your supplier know of which of the following connection types you require to ensure you get the right charger:
- Alligator clips
- Cannon plug (three pin). These are commonly used for mobility scooters and powered wheelchairs
- Lead and ring terminals
Need further advice about VRLA battery chargers?
The experts at Valen are happy to check your calculations for your VRLA battery charger or walk you through the calculations to ensure you purchase the correct charger for your system.
If you’d like more information, please click here to get in touch with our expert team. We’d be happy to answer any questions you have.