2 ms·

So aside from what's been said, I can get this for $200 http://www.batteryspace.com/Powerizer-LiFePO4-Battery-12V-15Ah-180Wh-30A-rate-with-PCB-and-LED.aspx http

• conjecTech 11y ago
  Storing a lot of energy and delivering it faster are two separate problems. The batteries you linked are design to store a lot of energy, but are only rated to deliver it at 30Amps. Cranking even a medium sized sedan would take 5x that or more. Creating something that can do that reliably requires a lower energy density. LiFePO4 by itself also doesn't stand up particularly well to cold temperature. The capacitors do most of the heavy lifting involved in starting the car. Using the combination of the two also enables some other nice things like the dead battery prevention.
• sliverstorm 11y ago
  Yes, the caps. Classically the reason we use lead-acid in cars is its tremendous power density. Here they are combining LiPo (high energy density) with caps (high power density). My truck battery pumps out 750CA for short bursts. That's about 12 horsepower. Lithium batteries can only accomplish that in large parallel banks.