Can I get the 21Ah battery instead of 18Ah battery and pay the difference? May 01, 2020 21:23 The 21Ah battery is only offered as an additional accessory for the time being. Related articles How fast can the D-class go? Which side is the throttle on? Are the tires puncture resistant on D-class? Is D-Class waterproof? I've recently had a flat tire, is it covered under warranty? Comments 0 comments Please sign in to leave a comment.