Charge & Discharge waveforms of lead acid battery Vs Super Capacitor

Basically, the lead acid battery charges much slower, stores *way* more energy, and then discharges just as slow.

On the other hand, the super capacitor can be discharged all the way down to zero volts; this will kill a lead acid battery.

Luhan

Go to a battery manufacturers website. Most have graphs of the curves for their batteries. There are a _lot_ of variables though. Batteries are a chemical device, and give a very flat output voltage for most of their discharge. However their ability to deliver power at high currents, falls faster than a simple 'resistive' loss, as a result of limitations in the rate of chemical action (also the actual resistance of the cell changes as it discharges). This gives a curve called the 'Peukert curve', which characterises how batteries perform at higher discharge rates. Batteries also have quite complex charge requirements, with many types undergoing accelerated decay if charged wrongly. A capacitor conversely has a relatively simple linear discharge, and can be charged by a simple voltage source, with a current limit to prevent damage. The battery has the big advantage that more of it's discharge cycle is spent at relatively higher voltages, making it simpler to make efficient use of the power.

Best Wishes