PSA: I just picked up the new 16" HP mower (P1190) and found that the 9ah battery fits just fine with plenty of clearance for the lid to close. I've seen a
Ryobi Tools UK
9AH 6AH LITHIUM ion Battery For Ryobi 18V ONE PLUS P108 RB18L50 RB18L40 RB18L13 - £22.59 | PicClick UK