Table of Contents
Preface
Battery pack are a significant cost when you build your own solar/RV/boat power systems. Therefore, you need battery solutions that have higher capacity, high power potential, longer life, sustainability, safety and that meet your needs.
Usually when you buy packaged battery product from the market, the manufacturer does not specify the brand/model of the cells inside, so we have no idea about the quality of the cells.
Knowing the quality of the cells is critical for a battery that is expected to last 7-10 years.
Compared the high cost of purchasing a battery pack, DIY battery packs can significantly reduce the cost, and we can control the brand and capacity of the cells. In addition, we can even increase the capacity in the future as needed.
LiFePO4 cells from EVE, CATL and LISHEN are currently well known by DIYers as high quality cells. Among them, EVE 3.2V 280Ah cell LF280N is the most popular. You can use 4 pieces of LF280N and a BMS to conveniently form a 12V 280Ah battery pack. But we have to make sure to buy A gauge battery cells and a high quality BMS.
Cell
For the cells, we recommend the EVE A gauge 3.2V 280Ah cells sold by Energie Panda.
The internal resistance of this cell is less than 0.25m ohms. It has a deep cycle life of over 3000 cycles under ideal conditions. Supports 1C/1C continuous charging/discharging. Supports 2C/2C peak current (due to the high capacity of 280Ah, there are few opportunities to reach 2C current in real use).
In the extreme case of one deep cycle per day, this battery can last for more than 8 years. I have to say that this is a very ideal battery cell. With it, you can easily build your own 12V/24V/48V 280Ah/560Ah system.
BMS
In an earlier article, we recommended Overkill Solar’s BMS board. It’s a great product. But today we recommend another great brand, DALY, which like Overkill Solar, is also very well known among DIYers. Better yet, it comes with a waterproof case and built-in fan.
DALY has a variety of intelligent BMS, the more commonly used are 4s/8s 100h and 150Ah.
The cost to DIY a battery pack
Let’s take the example of making a 12V 280Ah and a 24V 280Ah battery pack.
12V 280Ah battery pack
Materials Used:
- EVE 3.2V 280Ah battery cell x4
- Daly 4s 12V 200A BMS x1
The price of 4 cells is $730 USD(includeing shipping fee) and the price of daly 4s 12V 100A BMS is about $75 USD.
So the total price is about $805.
A commercially available packaged 12V 280Ah battery pack costs about $1200. You can save $400 or 30% by assembling it yourself.
24V 280Ah battery pack
Materials Used:
- EVE 3.2V 280Ah battery cell x8
- Daly 8s 24V 150A BMS x1
The price of 8 cells is $1388 USD and the price of daly 8s 24V 150A BMS is about $95 USD.
So the total price is $1483 USD.
The price of an assembled 24V280Ah battery pack in the market is about $2800 USD. DIY battery pack can save $1400 USD or 50%.
The above price calculation includes the price of the battery cells (including their shipping from China) and the price of the BMS. The required bus bar to connect the battery is usually included with the battery cells.
It should be noted that the purchased cells are usually shipped from China by sea. This process has been gradually extended to 2 months this year. The price of the cells mentioned above already includes the price of shipping. In addition, energie panda also offers a fast shipping service to the US in about two weeks. However, the price increases by about 20-30%. BMS is easily available on Amazon.
Conclusion
Generally speaking, the larger the capacity of the battery pack, the harder it is to buy in the market. In this case, DIY assembly of battery packs is not a bad choice.
In particular, we can choose our own big brand of battery cells, so as to control the quality of the battery pack and ensure that we can get a long life.
Sarah O'Connell
As a research member with a background as an engineer, Sarah believes we need to know enough about products before we buy and use them, especially those that require some expertise and ability to operate. Sarah is happy to share her opinion and what she has learned with everyone. She believes that conscious consumption is everyone's responsibility and that all content should be complete.