Good News! We are in the process of having an extended battery for MiFi 4620L manufactured and we should have it available the first part of June 2012. The MiFi 4620L Extended battery will be a whopping 5000mAH. The 4620L uses the same battery as the 4510L, HOWEVER, the battery door is completely different. Be sure to read the 4510L Extended battery reviews, to get an idea of what existing customers think of the extended battery. Be sure to signup to be notified when this is ready for order, we will allow pre-orders around 2 weeks before we get them in stock.