Joseph P O'Connor

I have spent twenty years engineering battery systems. This store is where I sell the parts I could not buy easily myself.

Most of my career has been on the large end of energy storage. Utility-scale battery systems, the kind measured in megawatt-hours, where the cell selection has to survive a third-party design review and a bad decision costs millions. I still do that work every day.

This store is the small end of the same discipline. Same chemistry, same failure modes, same questions about voltage windows and balance and thermal margin. The difference is that a home builder gets none of the engineering support that a utility project gets, and has to figure it out from forum posts.

That gap is the reason for the book, and the reason for this store.

The book

In 2016 I started writing Off Grid Solar because the resource I wanted did not exist. Everything available either covered grid-tied systems with off grid as an afterthought, or assumed you had already decided what to buy. I wanted a book that started at the load calculation and ended at a working system, used internationally recognized codes, and treated lithium as a real option rather than an exotic one. Today Off Grid Solar books are a flooded market with tons of AI slop books.

It is now in its second edition, in English and Spanish, and it is used as training material by companies that install this equipment for a living.

 

"One of the best solar energy books of all time."
- BookAuthority

 

"This is one of the first books on solar that I personally read and it has become required reading for our employees."
- Global Solar Supply

 

In the 2018 Outside Magazine article with Alex Honnold, the free solo climber, has Off Grid Solar on his current reading list. He was reading it because he wants to add solar to his van!

 

The field work

I have built and taught off grid solar systems in the US, Haiti, Guatemala, Nepal, Portugal, and Virunga National Park in the Democratic Republic of the Congo. Some of those systems power homes. In Virunga, we powered ranger stations deep in a rainforest where the nearest grid connection was miles away.

Micro-grid installations in Virunga National Park, Democratic Republic of the Congo, 2016. Film by the GivePower Foundation.