I have read this page: http://forums.minidisc.org/index.php?showtopic=7423 Where it is recommended to upgrade the battery to a 1400/1450mAh, but there are reports of higher capacity batteries swelling when charged in the NH900 - http://forums.minidisc.org/index.php?showtopic=12583&hl= I have a NH900 ordered (expecting it soon) so i'm sorta planning ahead. I can buy this 1350mAh battery pretty cheap (says made in Japan) http://www.dse.com.au/isroot/dse/images/products/s3399.jpg Specs: # Digitor replacement battery to suit most minidisc players, Sony Walkmans and other branded personal players. # 1.2Volt NiMH (Nickel Metal Hydride) 1350mAh # Replaces original batteries: SanyoHF-A1U, Panasonic HHF-AZ01, HHF-1PSC, RP-BP140H, HHF125T, Sony NH-14WM and Sharp AD-N55BT Any thoughts/info on replacement higher capacity batteries greatly apreciated, i don't want any bad batteries ruining my MD