Lithium Batteries are the most popular type of battery for the European and American markets due to the following reasons:
1) they are lighter in weight than lead acid
2) they have a longer life than lead acid

There are two main types of lithium battery being sold on the market today:  Lithium Iron Phosphate (LifePo4) and Lithium Manganese.  The process to create these cells is similar but the material between the anode and cathode is different.  LifePo4 cells have an advertised rating of about 2000 cycles per cell but when strung together in a pack this comes down to about 1000 cycles for a full pack.  Lithium Manganese have about 500 cycles but weigh less and cost less than LifePo4.

All lithium packs require a battery management system (BMS) to regulate the individual cells. Without a good BMS, individual cells could fail resulting in the loss of the entire pack very rapidly.  The purpose of the BMS is to ensure that all cells get charged equally and that no single cell ever goes below a certain minimum voltage threshold in case a single cell fails more rapidly than the rest of the pack.  If a single cell ever reaches 0 volts, the cell is permanently damaged.

A good lithium charger is also required for a healthy lithium battery pack.  Different cut off voltages apply to different chemistries.  Lithium Manganese cuts off at 4V per cell whereas LifePo4 cuts off at 3.85 per cell.

Many different manufacturers mainly based in China and Taiwan provide a wide range of qualities of Lithium cell, either in the form of loose cells or full packs.  If you are interested in introducing lithium cells as a replacement for lead-acid, the EV Future team can assist you in this.

Lead-acid batteries, invented in 1859 by French physicist Gaston Planté, are the oldest type of rechargeable battery. Despite having the second lowest energy-to-weight ratio (next to the nickel-iron battery) and a correspondingly low energy-to-volume ratio, their ability to supply high surge currents means that the cells maintain a relatively large power-to-weight ratio.
The VRLA (Valve Regulated Lead Acid) also know as MF (Maintenance Free) battery is one of many types of lead-acid battery.
It became popular on motorcycles because its acid is absorbed into the medium which separates the plates, so it cannot spill, and this medium also lends support to the plates which helps them better to withstand vibration.
The electrical characteristics of MF batteries differ somewhat from wet-cell lead-acid batteries, and caution should be exercised in charging and discharging them. MF batteries should not be confused with AGM (Absorbed Glass Mat) batteries, which also have an absorbed electrolyte but again have different electrical characteristics.

Environmental Concerns

Currently attempts are being made to develop alternatives to the lead-acid battery (particularly for automotive use) because of concerns about the environmental consequences of improper disposal of old batteries. Lead-acid battery recycling is one of the most successful recycling programs in the world, with over 97% of all battery lead recycled between 1997 and 2001.[2] Effective Lead pollution control system is a necessity for sustainable environment. There is a continuous improvement in battery recycling plants and furnace designs for greater efficiencies. These recycling plants are ecology friendly as they follow all emission standards for lead smelters, but new methods should be devised or alternatives developed to the lead-acid battery so that lead pollution can be reduced to an essentially negligible amount.