Did you know that you can use lithium battery packs to power everything from fishing kayaks to RVs to off-grid vacation cabins? Lithium batteries are reliable and versatile. However, you can't use the same battery capacity to power a single navigation bulb on a boat as you can power all the appliances in your house. Try this and you'll run out of power quickly.
That's why it's important to figure out how much battery capacity you need. Once you've done this, you can create the perfect battery pack for your needs.
What is a battery pack?
A battery pack consists of two or more cells connected together. They can be connected in series or in parallel. Doing so allows you to have greater energy storage capacity and power your devices for longer periods of time. Battery pack size refers to the number of batteries you need and what size they should be.
How to Size a Battery Pack
At first, figuring out battery pack sizing can seem like a daunting task. This is especially true when you have large energy needs, such as powering everything in your off-grid house.
But here's some good news: every electronic device tells you its electrical load consumption. Simply check the label or packaging. You can use this information to determine your total energy needs. This is the first step in sizing your battery pack.
So go grab a pencil, paper, and a calculator (or an electronic device, if that's more your style). Look at the electrical load consumption of each device to be powered. Then use the following steps to find out how much capacity your Li-ion battery pack needs.
Other Battery Pack Sizing Considerations
Batteries do not produce energy - they only store energy. Therefore, it is important to make sure you have a way to charge your lithium battery pack.
There are several ways to do this:
A charger connected to the grid
Generator
Solar power
Let's say you have a 200ah lithium battery bank, but your solar panels don't produce enough energy to fully charge it. Your bank will not be able to provide 200Ah and you will run out of power. In this case, you will have to get more or larger solar panels or reduce the amount of energy you use.
The good news? Unlike lead-acid batteries, lithium battery packs don't suffer any damage when partially charged. So the occasional cloudy day is no big deal. However, if your batteries are consistently undercharged, you'll need to pay for battery capacity that will never be used. In this case, it's best to choose a battery pack with a smaller capacity that you know can be fully charged.
For example, if you need a total of 40 amp hours to power a 12-volt application, connect two 12V 20Ah batteries in parallel. When you connect the batteries in parallel, the amps are added and the voltage remains constant.
If you connect the batteries in series, you can increase the voltage. For example, suppose you have a 24-volt trolling boat motor. You can make a lithium battery pack of two 12V 100Ah batteries in series, plus one 12V 125Ah to take care of the engine starter and other onboard equipment.
