Hello Larry B!
J & W. Maybe this will help you. I also have the B+ 225 and I wanted two batteries and after checking out the battery holder I measured it and realized that two SRM-24 batteries will fit into the holder if set side by side and if you bang the lip down on the front of the battery tray. I did mine more than a year ago and now never have to worry about running low on power. Just take your battery out and bang the lip doen flat so that the batteries will sit flat and than use a nylon strap to strap them in. They fit nice and snug . Measure your battery and than measure your tray and you will see what I am talking about. The lip takes a little work to bang it flat but it works out great!