More and more people are demonstrating an interest in server rack batteries. Before server rack batteries entered the home solar market, DIY battery packs were the preferred choice for home high capacity battery packs. So which will be the best choice now?
This post will compare the advantages and disadvantages of server rack batteries vs. DIY LiFePO4 battery packs. Hope it can give you enough reference.
Before we make a detailed comparison, let’s have a brief understanding of server rack batteries.
What is server rack battery
Server rack batteries are not a new thing. They have been used as UPS in data centers before. It uses the same specifications as the server case so that it can be placed in a standard server rack in the data center. Server rack batteries are designed to be compact and can make 48V 100Ah or 24V 200Ah battery in a 3.5U space, along with integrated BMS, circuit breakers and other components.
Advantages of server rack battery
- Small size
The size of server rack battery is between 1U and 4U according to the capacity.
- Easy to use
Using metal shell, LiFePO4 battery cells, safe and long life.
- Ready to expand capacity
Support up to 16 parallel.
Disadvantages of server rack batteries
- Not easy to carry
A 48V 100Ah server rackmount battery weighs up to 50kg; you have to use tools to move it.
- Not easy to repair
When a cell has a problem, it is difficult to replace; for a 48V battery, it usually has 16 or 32 cells inside.
- Not easy to monitor
Usually the only communication interface of server rack battery is RS485, which can only be monitored by computer, no Bluetooth interface; some server rack batteries are equipped with a display screen, which can view the voltage of each cell, SOC and overall voltage and current, etc.
So will server rack batteries be more acceptable than DIY LiFePO4 batteries? Let’s compare server rack battery and DIY LiFePO4 battery pack in detail in terms of cost/quality/convenience.
Server Rack Battery VS DIY LiFePO4 Battery
Here let’s compare the cost per kWh.
For the server rack battery we chose the most common model 48V 100Ah as our sample. The current best price for a 48V 100Ah server rack battery is around $1500. This is equivalent to $312.5/kWh.
Since the cost of DIY LiFePO4 battery pack varies in different regions. So let’s take the example of making a 48V 280Ah LiFePO4 battery pack in Germany by purchasing LF280k battery cells and accessories through Energiepanda. The specific costs are as follows.
The price of 16 EVE LF280k 3.2V 280Ah battery cells is $2550 (including shipping/duty/clearance to Germany, etc.).
Take JBD BMS as an example.
JBD 48V 100A BMS — $99
Take extra soft 4 AWG wire for example, 1 meter red, 1 meter black — $18
4, Ring Terminal
Ring terminal is mainly used for BMS balancing wire to connect to cell terminal and battery wire to connect to inverter/charger or power distributor.
The 48V 16 cell BMS requires 17 ring terminals — $3
4 ring terminals for use on 4 AWG wire — $3
5, Torque wrench — $35
6, Fuse/breaker — $20
7, Others (tape/wooden board/plastic box/heat shrink tubing/soldering iron, etc.) — $50
The total cost is about $2778 USD. which is equivalent to $194/kWh.
Comparing the cost per kWh, the cost of a DIY LiFePO4 battery pack is 62% of the cost of a server rack battery.
This shows that the current cost of DIY LiFePO4 battery is significantly lower than server rack battery.
The quality of the battery pack depends heavily on the cell, BMS, and protection measures.
A good battery cell will give you full capacity, stable output and long deep cycle life.
And a high quality BMS will ensure the safe use of the battery, as well as instantly balance the cells to keep each one in the same condition.
It is hard for you to know the brand and specifications used for the LiFePO4 battery cells in server rack batteries. Take a 48V 100A server rack battery pack. There are those that use 16 3.2V 100A cells and those that use 32 3.2V 50A cells.
Also due to the continued shortage of LiFePO4 cells in the market, it is difficult for battery pack manufacturers to use the same brand and type of cells for their battery packs. So you will see in the promotional materials that manufacturers usually list several brands of cells.
DIY LiFePO4 battery packs, on the other hand, give you the freedom to choose your cells. You can choose any brand and cell type you trust, such as the EVE LF280K.
The BMS plays a vital role in the safe use of the battery pack, and it provides maximum protection for the cells. It provides overcharge protection, over-discharge protection, short circuit protection, temperature protection, as well as cell balancing.
As with the cells, you can not to know what BMS they use inside exactly. usually server rack battery packs do not come with a Bluetooth module either, but some server rack battery packs come with a display that allows you to see the status of some of the cells.You can check the status of some of the cells, such as the voltage of each cell and the SOC, etc.
When it comes to hardware protection, server rack batteries have a definite advantage.
Since server rack batteries are made in the factory by professional assemblers, there are strong enough and correct hardware connections inside.
And many server rack batteries are equipped with circuit breakers and surge protectors.
And, most importantly, it has a rugged, all-metal enclosure.
However, assembling LiFePO4 requires some technical knowledge and experience, and there are certain hazards in the process.
Making the compression device and finding a suitable container is also a challenge.
Although DIY LiFePO4 battery packs give you the freedom to choose a fuse with a higher level of protection, such as a NH fuse or a Class T fuse, there are often bare leaks throughout the battery pack, which can be a certain safety risk in daily use.
In terms of convenience, the advantages of server rack batteries are more obvious.
First of all, server rack batteries are a complete commodity, and they have the property of being ready to use. Once you buy it home, you can start using it immediately.
Whereas DIY LiFePO4 battery packs require up to 2-3 months of preparation and you have to wait until you collect all the materials before starting to make them.. The process of making the battery pack, in turn, requires Diyer to have some electrical knowledge and hands-on skills.
Secondly, although the server rack battery is heavy, it can be quickly moved to a new location and start working with the help of certain tools.
The DIY LiFePO4 battery pack, on the other hand, is not mobile enough, and sometimes you have to disassemble first and reassemble it in a new location. This makes it more difficult to move around.
While using high capacity battery cells you can easily make high capacity battery packs of around 300Ah, and server rack batteries can be connected in parallel with multiple packs to achieve the same purpose.
The above is a rough comparison of them from just three aspects of cost/quality/convenience.
Although it is difficult to compare at once which is more advantageous between server rack battery packs and DIY battery packs, we can draw the following conclusions from the above.
The cost of the server rack battery pack has currently entered the acceptable price range, although we can not know the specific cell type it uses and the BMS used, but this is the fastest way to set up your energy storage system.
DIY LiFePO4 battery packs can give you the most freedom, you can pick the type of cell you trust and the BMS you trust, and you can expand almost infinitely. Most importantly, you can build almost twice the capacity of the battery pack with the same price.
For people who want to build solar systems quickly and on a budget, server rack battery packs are the way to go.
For people who enjoys the process of building things, DIY LiFePO4 battery packs are the way to go and you can have a high quality, high capacity battery pack for the lowest cost.
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