The Stanley site says the 40 amper is discontinued. Hard to tell what would be a good choice.
https://www.baccusglobal.com/I think this one would do nicely. It does 30 amps at first and when the battery is full (by however it thinks it is) it automatically drops to Float. It is regular price at $149 (Can) in Can Tire, check for it on amazon.com for US price.
https://docs.wixstatic.com/ugd/217982_95ac1e45cb874794874d00669b63d4b1.pdfHere it is:
https://www.amazon.com/DEWALT-DXAEC80-Battery-Charger-Maintainer/dp/B06XDJZC1M/ref=sr_1_1_sspa?keywords=Dewalt+80+battery+charger&qid=1555179039&s=gateway&sr=8-1-spons&psc=1
