Arduino Lithium Ion Battery Charger

• Decent instructional at http://henrysbench.capnfatz.com/henrys-bench/arduino-projects-tips-and-more/arduino-18650-battery-charger-project-1/
• Uses Arduino and common parts
• Current limit is 2.5A - but could run at 4v or up to 40V limit, so probably 24V limit. 100W limit. Good for overnight battery charging of a bicycle pack (1kW)
• Project itself suggests 4v at 2.5A - so about 10W limit.