When a lead-acid battery is overdischarged to an excessively low level, permanent damage will result. The same thing will happen to a lithium battery. All lithium batteries are deep cycle capable, they just cannot be excessively discharged past empty (over-discharged). Because of this, Voltphreaks batteries contain a Low Voltage Cutoff (LVC) to prevent damage from over-discharge.
One side benefit of the LVC is that you will almost
never return to a dead car if the car is parked for long periods. By setting the LVC to shut off the battery just before the battery is completely empty,
you almost ever return to a dead battery if you park your car for, say 3+ weeks. Check out a demo below of the
LVC feature protecting a BMW M3 from a drained battery.
One common misconception about the LVC is that it will shut off your battery when you park and you will lose radio, alarm, and other settings, while this doesn't happen with a lead-acid battery. This isn't true, for all intents and purposes you can actually pretend the battery doesn't have an LVC, since the LVC shuts off the battery when the battery only has a little bit of energy left. For example, consider a Voltphreaks VPH750 with LVC, and a lead-acid battery (no LVC) of the exact same capacity.
For the VPH750 with LVC, battery will shut off and you will lose your radio and settings after parking the car for 2 weeks. With no LVC, you'd still lose your settings when the VPH750 drains completely after 2 weeks and 6 hours (the additional 6 hours is because the LVC shuts off the battery before it's completely empty so you still have energy to start the car).
For the lead-acid battery of the same capacity, you'll STILL LOSE your alarm and radio settings after being parked for 2 weeks and 6 hours (same as the Voltphreaks with no LVC). This behavior is the EXACT SAME as with the Voltphreaks battery, except that you get 2 weeks "park time" with the Voltphreaks and LVC, versus 2 weeks + 6 hours with the lead-acid, and you will need to jump-start the lead-acid battery. With your Voltphreaks battery, you will not need a jump-start, just press a button to turn your battery back on, and start your car. Though you can still give other cars jump-starts!
If your car is a daily driver or regularly driven (at least once every week or two), then your Voltphreaks battery will never cutoff. This is because you don't leave the car parked for long enough periods. If you do plan on leaving your car parked for long periods, Voltphreaks batteries are compatible with trickle/float chargers that properly stops charging when the battery is charged. We recommend the Deltran Battery Tender Jr. Or, if you plan on leaving your car parked for long periods, you can always shut off the Voltphreaks battery after storing your car.