How to Select Battery Charger

There are few considerations that need to be taken cared of on how to select battery charger. They are:

  1. Type of battery to charge
  2. Ampere-hour rating of the battery
  3. Voltage rating
  4. Maximum charging current
  5. Features wanted
  6. Mechanical aspects
  7. Grid voltage
  8. Cost

How to Select Battery Charger Explained

Type of Battery to Charge

Maybe the first thing you keep in mind on how to select battery charger is the chemistry of the battery. Above are just common battery types. They have different characteristics and thus need different charger. You need to be mindful what is the type of your battery. A battery is can be lithium-ion, lithium phosphate or any derivatives, or a lead acid-based battery, etc. Different battery chemistry requires specific charger. For lithium derived batteries, you need to buy a charger with a very sharp output voltage regulation as Lithium based batteries are very sensitive to over voltage. Always check your battery and look for the manual and check the recommended charger. If not indicated, then select the charger based on this article.

I visited Analog Devices product portfolio, as you can see below table, there are different charge control ICs for different battery chemistry. That means a specific charger is designed to a specific battery chemistry.

Ampere-hour Rating of the Battery

Another thing that you must consider battery charger selection is ampere-hour rating. Every battery has specified ampere-hour rating. This is related to the charge storage of the battery. If your battery is big enough say having 10Ampere-hour, then you should not buy a charger that has a charge current of 1A. If so, then it will take your battery to get fully charge by 10 hours. You don’t like this. An ideal charging time for batteries is can be 1-2 hours. Refer to below sample calculations on charging time. Note that this is not that accurate. Charging current is not all the time at its maximum. When the battery is near full charge, charging current usually decreases.

Voltage Rating

This voltage rating is the maximum floating voltage of the charger. The charger max voltage must be 7within the battery max voltage rating. For instance, the battery used is Lithium-ion that is rated 3.7V per cell. Your charger must not exceed this level. Otherwise, the battery may get damage too soon or even exploded right away. Below is an example Lithium rechargeable battery advertised at Ali Express. Each one is rated at 3.7V. So, your charger voltage should not exceed this level.

Maximum Charging Current

Another thing to consider on how to select battery charger is the maximum charging current. Maximum charging current is the maximum current that can be supplied by the charger despite the battery request more. It will stay to this level. When the battery is near full charge, the charging current will slowly decrease. The maximum charging current will mostly happen when charging a battery with very low charge left on it. If your battery is too big, you don’t want to buy a charger with a very small charging current. The battery will take very long time to get full charged. Target a charging time of 1-2 hours or as advised by the battery manual you have. From this, and given the size of your battery, you can compute the charge current that your charger must have.

Features Wanted

The deciding factor to consider in buying a charger with plenty of features are the cost of the battery and safety. If your battery is very expensive, then consider buying a battery charger with some features like over voltage, over current protection and safety features. This just maybe an add on to the basic functionalities. However, if you have good budget, then go for it. Specially for the safety related features.

Mechanical Aspects

This is another important aspect to consider in battery charger selection. You need to consider the termination of the charger if compatible to the battery. You need to consider if the charger is handy enough as what you after of. You need to consider if the charger input port is compatible to your wall outlet and so on. You need to consider if the battery can fit in to the charger slot, etc.

Grid Voltage

Another very important to consider on how to select battery charger is the compatibility to the grid voltage. Grid voltage is the voltage that you can get from your wall outlet. Nowadays, chargers can accept a wide range of input as what they say universal line from 90-264Vac. Just in case, always check the charger input if compatible to your wall outlet. For instance, a US version charger must be rated with 110Vac and not 220Vac. Otherwise, the charger will get damage or may explode.

Cost

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