You already know that batteries are an important component of portable electronic devices, but they’re also critical for a sustainable future on a larger scale. Eco-friendly means of generating electricity, like solar panel arrays and windmills, can’t provide on-demand energy whenever it’s convenient for us. Solar panels can obviously only generate electricity when the sun is up and windmills don’t provide anything when there isn’t wind. It is necessary to store the energy from the peak production times for later, which is the perfect application for this massive battery pack made from 2,800 individual 18650 lithium-ion battery cells.
It might not be necessary for you to use a battery pack like this if you just have some solar panels on the roof of your residential home, as you should be able to sell that electricity to the power company and then buy it back when you actually need it. But if you’re living off-grid or in a location where that isn’t an option, this kind of battery pack can get you through the nights. This specific battery pack contains 2,800 18650 battery cells, each of which has an average capacity of 2600mAh. It has a total of 500aH capacity outputting at 48V, with roughly 25kWh of useable storage. The average residential household in the US uses 30kWh per day, so this is easily enough to get through a full day if you have efficient appliances.
This battery pack, which was shown on the HBPowerwall YouTube channel, was built entirely using 18650 lithium-ion cells that were recycled from used laptop batteries. 18650 cells are incredibly common, so they’re easy to find in discarded electronics. But those cells have to be properly charged and balanced like any other lithium-ion cell, which is why these were sorted into groups based on their capacity. They were connected using fused nickel strips from batteryhookup.com and thick copper wire bus bars. This particular battery pack was designed to be used as a DIY Tesla Powerwall, but the lessons you can learn from the video can be applied to any 18650 battery pack.