I'm looking at using a stock Sparkfun LiPo/Li-ion Battery Babysitter to charge an array of four 18650 Li-ion rechargeable batteries (Panasonic) in parallel, keeping the pack voltage at 3.7V. I chose the charger because it has excellent monitoring and control on-board. I read the data sheet for the Texas Instruments charge controller and it had the needed protection for the unprotected batteries (under-voltage, over-voltage), with the over-current protection provided by a simple fast-blow fuse.
The only issue is that the charger only runs at 1.5A max current. Considering that the battery array is capable of taking more than four times that rate, is there going to be an issue charging so slowly? I've seen Sparkfun recommend this charger for their 3.7V LiPo pack that uses three 18650 batteries, so I figured it would be fine and just charge very (very) slowly. If it's necessary, I suppose I could wire up two chargers and split the batteries between them, but I don't mind the slow charging rate if it won't hurt the batteries.