Yes! The Jumpr Stack 3, 6, and 9 all support pass-through charging.

Our new Jumpr Stacks 3, 6, and 9 do come with built-in Lightning connectors to power your iPhone 5 or 6.

For the new Jumpr Stack 3,6,9 Series, there is no technical limit to how many you can stack. As this product has “Stack and Charge” as well as “Stack and Discharge” features, it is designed so that it stays safe when stacked, either charging or discharging. This means if when stacked 3-high and charging, the charging time will 3X of nominal assuming all the batteries are at an equal charge level. When stacked 3-high and discharging, it can discharge at its maximum current 3X as long duration, again assuming all of the batteries are at an equal charge level. Although there is no technical limit to how high you can stack them, we recommend the limit of 3. The thinking behind this recommendation is that the electrical connections that are made when stacking the devices are not as good as made when using a cable. This means there is some small power losses when stacking, and we feel 3-high is a conservative and practical limit to minimize those additive power losses.

This is only one battery. The numbers at the end of that Stack Series represent the battery capacity of each product. The Stack 3 is 3,200 mAh, the Stack 6 is 6,200 mAh and so on. Any of these batteries however, can be stacked on top of each other for simultaneous charging, even if they are different batteries altogether (example: stack a Stack 3 on top of a Stack and and both will charge together)