Really disappointed with this unit. This gives an approximate charge time for different battery sizes, but a high capacity battery says a pair of D 5k-10k Mah cells will literally last WEEKS. The estimated charging time generally refers to batteries with a capacity of less than 500 mAh. Even the lightest AAA battery is usually 1500mAh, ie C Crane is a good company in general - I've known them and been buying their products for many years and it's because of that reputation that I bought this unit. Charge rates are ridiculous in the real world, and C Crane is primarily meant to be ahead of the curve, so it's a surprise! The lid needs to be tilted at an angle to the sun for optimal charging, but this is a simple hinge that doesn't hold the lid at a specific angle - an easily fixable but ill-considered design. The springs holding the batteries to this device were missing or broken so that didn't work. God! Buy almost anything else but NOT this!