An LEV battery pack is just that, a pack or collection of cells usually lithium-ion manganese in chemistry. The cell types for light electric vehicles generally come in 3 cell types. Laptop size 18650, thin li-polymer foil layers, or larger prismatic rectangles.
We prefer the more name brand-name Panasonic, Sony, LG and Samsung 18650 cells for reliability, stable warranty, safety, and for marketing reasons.
Although those 18650 packs are not created equal either. Most conservative Panasonic packs are generally 1C discharge “laptop” rated cells intended for the EU style 180~250 watt motor set ups. These packs generally work great in lighter load situations.
1C rated packs are not really suitable for the heavier weight and power hungry demands of the North American market. If you are going the route of a 350~400watt motor set up that uses a speed sensor or throttle, you would probably want to have a “high power” 3C rated pack. For 500watts something more along the tune of a “high power” 5C rated pack. 3C and 5C cells are generally made for more demanding “high power” applications like portable drills and saws etc….
Some of the new BUS and other language protocols for LEV systems allow for a smart chip to log user data in the battery’s BMS (battery management system.) Now with a special USB data extracting box, a dealer or vendor can extract user data like:
-battery serial number
-total cycle count
-last charge or plug in cycle
-over stressed cells
-over heated cells
-and individual cell SOC (state of charge)
Gone are the days of consumers in a colder climate like let’s say the state of Maine, leaving a fully discharged pack unconditioned from August till May, and getting a free warranty pack from their dealer. Our battery engineers suggest plugging in the battery pack at least 2 hours/ every 2 months for optimal life cycles.
While these types of packs and diagnostic software will cost you more per unit upfront, in the end they will save you a lot of money in false claim warranty. They will also resonate with your dealer base as a sign of quality and act as a key marketing tool.
So keep this in mind the next time someone tells you about a new “non-brand name cell” battery company with a special new pack, that is cheaper in price. You get what you pay for in the end……..
*Update 2/15/15 Pedego recalls 5000 e-bike batteries. http://www.bicycleretailer.com/recalls/2015/02/09/pedego-recalls-5-000-e-bike-batteries#.VP3rxUZnhng