Up for sale is a genuine OEM Ryobi 48V Lead-Acid Battery Charger, Model OP48RM (Part # 140448001). This came from a working setup. While visiting I mowed using the old charged batteries, and then helped my son replace the 4 AGM batteries with Lithium batteries (more amp-hours) which required a different charger to fit the lithium charging profile needs. He was going to metal scrap this charger (didn't want to spend the eBay time) but I offered to sell it since I am retired and I really really don't like throwing away something perfectly functional (I can't park our cars in the garage because it is filled with "stuff" I or the grandkids might need).

Plugs into standard 3-pin mower ports. Showing normal cosmetic wear from garage storage but functions perfectly. 

This charger came with mower model and other info (shown in the last photo):

Ryobi RY48111 Riding Lawn Mower
48V -- 100AH  38 inches
For use only with SC-48 or OP48RM charger

The info on this charger's metal plate (shown in one of the photos):

RYOBI OP48RM (140448001) Battery Charger
Battery Lead-Acid AGM 24 Cell 50-100Ah
Input  120V ~ 60Hz  500W
Output 48V -- 7.5A

Let me know if you have any questions.