Before selecting a charger for your battery there are a few thing or questions that you need to consider.
How to know which charger will fulfil your needs?
First, determine what type of sealed lead acid battery you will be charging: Maintenance Free, Wet Cell (flooded), AGM (absorbed glass mat), Gel Cell or VRLA (valve regulated lead acid). In most cases one battery charger will work for all types except for Gel Cell. If you have a Gel Cell SLA battery, you will need to find a specific charger. Once you’ve determined the battery type, you will need to know the battery’s voltage and amp hour rating. Typical battery charger voltages can range from 6 or 12 volt, which corresponds with your 6 or 12 volt SLA battery. Typical SLA battery charger amp hour ratings can range from 0.3 to 10 amp hours but it can go beyond that. To determine the correct amp hour charger, you will need to find the maximum rate of charge of your sealed lead acid battery. Typically, this is printed on the side or front of the battery. For example, it will state “initial current – less than 2.1 amps”. This means a charger the size of 2.1 amps or less needs to be used.
What size charger should you buy for your sealed lead acid battery?
The battery charger size you choose depends on the charging current required to restore your battery to full charge. You may want a quick recharge of your sealed lead acid battery, which requires more amps from your battery charger, in which case you would need to purchase a charger with a higher amperage rating. Other times, you may select a smaller charger with fewer amps. This will increase the time it takes to charge your SLA battery, which is fine if you’re not in a rush. The most important thing to note here is to make sure you have enough power from your charger to do the job you require in the time you allocate.
Exactly how long will it take to recharge your sealed lead acid battery?
The length of time to recharge your batteries depends on the battery and charge size, varying anywhere from 2-24 hours. To calculate an approximate total charge time, a good rule of thumb is to take the amp hour rating of the SLA battery and divide by the charger rating, and then add 10% for the extra time to completely top off the battery. For example, to fully recharge a 12 Volt 7 Amp Hour (12V 7Ah) SLA battery using a 12V 1.8Ah charger would take approximately 4.5 hours if the battery is fully discharged.
Once you’ve thought through these questions then you can easily chose the battery of your requirement.
The battery chargers that come in the market usually look like this: