A couple of readers of our post about the home built electric trike commented about the batteries. As I noted in the post, that particular build was completed in 2013, so it’s using battery technology available then, but the whole field is advancing pretty fast and you could design a better solution if you decided to build one now. In fact, I came across a pretty cool book, DIY Lithium Batteries – How to Build Your Own Battery Packs, that shows how to create exactly what you need, and not having built any electric vehicles, I didn’t even know building your own packs was an option.
In the same way we’ve written about builders casting their own metal parts when building a conventional motorcycle, the DIY crowd putting together electric vehicles sometimes gets down to pretty basic assemblies, as well, which makes them a lot more interesting to build.
Micah Toll, the author, is a mechanical engineer who has been working in the ebike and electric vehicle industry and he’s built up quite a store of knowledge on the subject. He found that lithium batteries, used by manufacturers everywhere in all sorts of products, are made specifically for their needs, but the ones you can buy for your project are often the wrong size or capacity or shape, so you’re forced to adapt your project to fit what’s available, unless you build your own battery packs and most of us wouldn’t consider doing that because what most of us know about lithium batteries is pretty limited.
What’s in the book?
Micah begins by breaking down the various form factors; pouch cells, prismatic cells, cylindrical cells and then the various types; lithium ion, lithium manganese oxide, lithium cobalt oxide and on and on. Following this, he describes the pros and cons of each type. So far, so good.
Now comes the good stuff. He discusses sourcing the individual cells you’ll need for your packs, cell rating which deals with things like capacity, maximum discharge rate, maximum charge rate etc. which is what you’ll need to know before you can actually combine the individual cells into the packs you’ll be using in your own project. There’s a section on battery management systems, another chapter on construction methods, it really covers all the bases. If you want to build something with electric power that doesn’t have to be plugged in all the time, this book will get you started.
This book is like another book I reviewed a while back, Motors for Makers, which explained electric motors in a similar fashion, no heavy theory, but lots of practical knowledge that will sort through the terminology and types of components you need to know and understand if you’re going to build something running on electrons.
It doesn’t matter if you’re an electric enthusiast or not, these things are coming, electric motorcycles and cars are already here and Tesla is teasing electric pickup trucks and an electric semi tractor to be fully revealed later this year. You might want to keep current, no pun intended, with all of the technology. It’s something you’ll likely be dealing with if you’re going to be working on or building vehicles in the future or anything else that needs a battery and these books are a very understandable intro. Check ’em out.