Guidelines for Battery Charger Selection

Lead Batteries

Lead-acid is the oldest rechargeable battery in existence. Invented in 1859, lead-acid was the first rechargeable battery for commercial use. Even today, they are massively used in cars, wheelchairs, scooters, golf carts and UPS systems.

Charging of Lead Batteries

 

A lead battery’s nominal voltage is 2 V for each cell. There are different types of Lead cells: Gel, AGM, Wet and Calcium. Optimally they need to be charged with different Charge-End Voltage, namely: Gel batteries: 2,36 V, AGM: 2.43V, Wet: 2.47V, Calcium: 2,58V.

Lead-acid batteries are not really suitable for fast charging. Usually, charge time is 8 hours or even more. The maximal charging current depends on the battery capacity. Typically, it should be around 20% of battery capacity (0.2C) and should not exceed 30% (0.3C). Only some lead batteries are appropriate to be charged at 0.4C. Please refer to the batteries data sheet in order to properly charge them.

A periodic fully saturated charge is essential to prevent permanent battery damage. A lead battery must always be stored in a charged state. If you leave the battery in a discharged condition you may cause sulfation and consequently, the destruction of your battery.

If a lead battery is not used for a longer time, (e.g. motorcycle batteries during the winter period) it is very convenient to use a charger with the so-called maintenance profile. In this case, the permanently connected charger will measure the battery voltage and charge it automatically. All MEC charges have this function.

 

Lead-based Battery Charger Calculator

Lithium-based Battery Charger Calculator

Lithium-based Batteries

Lithium-based rechargeable batteries have not been around for a long time; they are still very young. There are more types of Lithium-based batteries: LiFePO4 batteries, Li-ion batteries and Lithium polymer batteries. Performance, cost and safety characteristics vary across types of lithium-ion batteries.

The nominal voltage of a Lithium-based cell depends on the chemistry used (for specific information, see the text below). The nominal voltage of the whole battery depends on the number of cells connected in series. It is a common practice to mark the voltage of the Lithium-based batteries with the number and the letter S. For example, a battery marked with 7S, it means it has 7 cells connected in series. Nominal voltage is simply calculated with simple multiplication of the cell’s nominal voltage and the number of cells (S).

General information about charging of Lithium-based Batteries

All Lithium-based batteries are suitable for fast charging. The maximal charging current can go as high as 100% of the battery capacity (1C) if really needed. However, please note that charging with so high current is suitable only for occasions and not for constant use, as this practice will shorten the battery life.

If you have the case that you need fast charging we recommend ordering a special charger with two charging profiles: where you can choose how fast you want to charge the battery. Majority of MEC charges can be ordered with multiple profiles. Please use the form below and send us an inquiry if you are interested.

LiFEPO4 Batteries

The LiFePO4 (Lithium Iron Phosphate) presents the safest Lithium battery type currently available on the market today. Characteristics are small size, they are light in weight and most importantly, they have a high energy density. In its lifetime it can reach more than 2000 cycles. LiFePO4 batteries have a very good temperature resistance.

Charging of LiFEPO4 Batteries

LiFePO4 battery’s nominal voltage is 3,2 V for each cell, end Charge-End Voltage is 3,6V per cell. The maximal charging current is typically 25% – 50 % of the battery capacity (0.25C – 0.5C) but can also go as high as 1C.

Li-ion Batteries

A lithium-ion battery or Li-ion battery is another type of rechargeable battery. Lithium-ion batteries are commonly used for portable electronics and electric vehicles and are growing in popularity for military and aerospace applications.

Charging of Li-ion Batteries

Li-Ion battery’s nominal voltage is 3,6 V for each cell, end Charge-End Voltage is 4,2V per cell. The maximal charging current is typically 33% – 60 % of the battery capacity (0.33C – 0.6C) but can also go as high as 1C.

Feel free to contact us if you still have questions:

Our experts will be glad to help you to find the most suitable solution for your needs.