Dyness A48100 Lithium Battery Bank Features

In this article we want to introduce our readers to the new A48100 battery bank from Dyness.

We want to talk a little about how to interpret the information found in the manufacturer's data sheet.

It is always interesting to talk about this equipment, as it is important to remember that using lithium battery banks requires some special care.

As we already talked about other articles from Canal Solar, the application of lithium batteries is different from what was done in the past with lead acid batteries.

Lead acid batteries could be purchased from a variety of suppliers and could be connected to virtually any type of inverter. The user himself could form battery banks, connecting the batteries in series or parallel, according to his needs.

Lead acid batteries have currently been replaced by lithium ion batteries, which have many advantages such as greater storage capacity and longer lifespan, with a much higher number of charge and discharge cycles than lead batteries.

However, despite their advantages, lithium batteries require special care. They must always be accompanied by electronic BMS (battery management system) circuits, which equalize the voltage of the battery cells and monitor variables such as temperature, total bank voltage, current and state of charge.

For a storage system with lithium batteries to function properly, it is necessary for the battery bank's BMS system to communicate with the inverter. Fortunately, the user rarely has to worry about this too much. The concern must occur at the time of project design, when the components are chosen and specified.

The main battery bank manufacturers normally approve their equipment with the main inverter manufacturers. When designing a solar energy project with storage, or simply a pure storage system, it is only necessary to check whether the desired battery bank is on the compatibility list provided by the inverter manufacturer.

In the images below, for example, we find an example of a system that uses Growatt inverters and Dyness battery banks. To make this combination possible, the two manufacturers talked to make their equipment compatible.

During installation, the equipment must be connected using special communication cables and the necessary adjustments must be made to the inverter and battery bank (according to the instructions provided by each manufacturer) so that the two equipment communicate and operate safely.

Features of the A48100 battery bank

The main features highlighted by the manufacturer are:

• High capacity – 4.8 kWh per unit;
• Accepts several installation modes: vertically, on the ground or on the wall, or with stacked units;
• Possibility of expansion: the product accepts up to 40 units operating in parallel;
• High security: monitoring and balancing at cell level;
• Compatibility with the main inverter brands.

In the equipment data sheet we find the following table:

The table above shows us that the A48100 battery bank uses LiFePO4 (lithium-iron-phosphate) technology, which is one of the safest (against the risk of fire) among the various existing lithium-ion battery technologies. The manufacturer then informs the energy storage capacity, which is measured in kWh (kilowatt-hours). In this case, we have a 4.8 kWh device.

After the energy storage capacity, we see the charge storage capacity, which is 100 Ah. This information and the previous one are closely related, as the amount of energy that a battery can store is directly related to its charge storage capacity.

It is easy to check the relationship between charge and energy. The table also informs that the battery bank operates with a nominal voltage of 48 V. We know that Energy = Load x Voltage, so we have:

Load = 100 Ah
Voltage = 48V
Energy = 100 Ah x 48 V = 4,800 Wh = 4.8 kWh

Other important information is found in the table, such as the maximum charge and minimum discharge voltages, respectively 54 V and 42 V.

The charge and discharge rate, according to the table, is 0.5C. That is, if the battery has a capacity of 100 Ah and has a C-rate of 0.5C, it can be charged with a maximum current of 50 A and needs 2 hours to acquire the maximum charge, since 50 A x 2h = 100 Ah. The same reasoning applies to the unloading procedure.

The table confirms the considerations in the paragraph above by informing that the maximum charge or discharge current value recommended for this equipment is 50 A.

Despite the recommended maximum nominal current of 50 A, the equipment supports a peak current of up to 75 A. This means that charging and discharging must preferably occur respecting the nominal current, but the equipment can deliver more power to meet consumption peaks, when this is eventually necessary.

Next, we find generic information on the dimensions, weight and operating temperature, among other things, in the table. An important piece of information is the number of cycles supported by the device: 6000. This means that the battery bank can be fully charged and discharged 6000 times.

Considering that the equipment will be fully loaded and unloaded every day (an extreme situation), the product will last 16 years, a very long time. As, in general, charging and discharging do not occur fully and daily in most applications, a durability of more than 16 years is expected, compatible with the life expectancy of most photovoltaic systems.

Finally, we find information about the degree of protection (IP 20, that is, the equipment cannot be exposed to rain), the possibility of parallelism (40 units) and brands of compatible inverters: Victron, SMA, Goodwe, Solis, SAJ, Growatt, Deye and others.