John Allen Byrne (1944–2025)

Frederick, Maryland and Portrush, Northern Ireland

John Allen Byrne, 81, of Frederick, Maryland, passed away peacefully in the company of family in Connecticut on December 28, 2025.

Allen was born in 1944 in Coleraine, County Antrim, Northern Ireland, one week after D-Day, to Terence Arthur Byrne and Anne Bridget Byrne (née Murphy). He was raised in the seaside town of Portrush. Growing up near the Giant's Causeway and learning the game of golf at Royal Portrush Golf Club, Allen spent his youth on Northern Ireland's Atlantic shore, a natural setting that forged a fierce independence and inspired him to see the world.

After attending St. Patrick's College in Armagh, Allen joined the British Royal Air Force (RAF) where he served on NATO missions and alongside the United States armed forces. His postings spanned 23 countries around the globe, including Singapore, Hong Kong, and NATO Communications Headquarters in Northwood, England. He was honorably discharged on June 26, 1974.

Following his military service, Allen furthered his studies at Havant and South Downs College in Hampshire, England and then began an international civilian career in power systems engineering. While working in Riyadh, Saudi Arabia, he met his wife, Maura, a nurse at King Faisal Hospital. In 1979, the couple moved to the United States, ultimately settling in Frederick, Maryland.

In the U.S., Allen became recognized around the world as an expert in battery-backed power systems. He rose to the role of President at System Engineering International (SEI), co-founded PowerConsult, Inc., and served as Senior Staff Engineer for American Power Conversion (APC). In 2012, he was inducted into the International Battery Hall of Fame. He retired in 2016 as a manager for Interstate Batteries' PowerCare Division, though he continued to consult through his firm, Brass Tacks Power System Advisors LLC, and in one of his most enjoyable roles, with Eagle Eye Power Solutions. Allen was a Senior Member of the IEEE and was one of the founders of Battcon, the premier annual U.S. conference for stationary battery professionals.

Allen was deeply committed to the Frederick community. He was a longtime member of St. John's Catholic Church and served on the Frederick County Economic and Community Development Commission. His spirit of service was evident in his work with the Kiwanis Club of Frederick, including a term as chapter president, Mission of Mercy, and his years spent "ringing the bell" for the Salvation Army. Passionate about rugby, he was a past president of the Frederick Rugby Football Club. He also belonged to the Marine Corps League Shangri-La Detachment 118 and the Frederick Elks Lodge 684.

Over the years, Allen remained a proud and devoted son of Ireland, serving as State Historian for the Ancient Order of Hibernians of Maryland. For over a decade, he also shared his encyclopedic knowledge of Irish history and music with the community as a special guest host of a St. Patrick's Day program on WFMD radio.

Allen maintained a dizzying array of interests and hobbies, from coins and stamps, to making incredible chili for local competitions, to driving Route 66 end-to-end on his own in 2017. He was a man of intelligence, wit, candor, and quiet resolve, who deeply loved his family. He will be greatly missed by all who knew him.

Allen is survived by his devoted wife of 46 years, Maura Byrne; his five children and six grandchildren, who were his greatest source of pride: Oona O'Flaherty (Don Murray) and children Aidan and Kate; Deirdre O'Flaherty (Luke McBride); Conor MacAllen O'Byrne (Hanna) and sons William, Ian Tadhg, and Tomás; Liam Martin O'Byrne; and Aunia O'Byrne (Liam Briody) and daughter Fiadh. He is also survived by his brother, Arthur Byrne, and family of Ballymena, County Antrim.  He was predeceased by his parents and his brother, Martin Byrne.

Friends and relatives are invited  to attend a Mass of Christian Burial  on Saturday, January 24th at 11:00a.m. in St. John The Evangelist Roman Catholic Church, 118 East Second Street, Frederick, MD

Following the Mass, there will be a Gathering in Remembrance from 1:00 - 4:00 p.m. at Frederick Elks Lodge No. 684,  289 Willowdale Drive, Frederick, MD

Plans for North Ireland will be announced.

In lieu of flowers, donations may be made to the Kiwanis Club of Frederick in his memory at: www.frederickkiwanis.org

To offer online condolences please visit: www.boutonfuneralhome.com