I’m looking for a portable cell phone charger based on 18650s. It must be compatible with the iPhone 3GS and iPhone 4. Since I’d like to use my current stock of 18650s it must be able to use protected cells. It should be able to charge 18650s in addition to using them for power to recharge other devices. What would be the best portable 18650 charger for phone? I would really appreciate your useful information regarding this. Thanks.