Because sometimes you just need more than 3.7V!
I’m aware you have single-cell chargers with step-ups, but these are not suitable for robotics applications such as driving motors or larger sensors. The only one I’ve seen that approaches feasibility is the $55(!) AnyVolt 3.
I know this can be done economically. There are several chips available to accomplish this task such as [this one i found in 5 minutes on digikey. Personally though I have neither the components to design my own circuit for the chip nor the desire to order 100 of them.
I’ve looked around at your competitor’s sites and can say with some certainty this a useful item nobody is selling.
Some features I would love to see on such a module would be:
-Native support for solar charging (ie. no timeout, reasonable efficiency and undervoltage / undercurrent tolerance)
-charge rate adjustable by onboard screw pot
-breadboardable
-indicator LEDs
-double screw terminals for the battery (power in / out kind of thing)
-onboard 5V source (ideally a switch mode reg)
Thanks for taking the time to consider this idea!](http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-2233-5-ND)