Progressive Dynamics, Inc. has introduced a new lithium battery converter/charger, Inteli-Power 9100L Series designed for use in golf carts, electric vehicles, solar power storage, ups power back-up systems, forklifts and similar applications. These 12-V and 24-V lithium-ion battery converter/chargers are designed to meet the stringent voltages required for properly charging and maintaining lithium batteries. Lithium ion batteries require special balancing circuits and chargers to prevent overcharging a cell or discharging too much.
Standard features of the Inteli-Power 9100L Series converter/chargers include reverse battery protection, electronic current limiting, low line and high voltage protection and a variable speed intelligent cooling fan. Units also deliver filtered dc power to the lithium ion battery to ensure the built-in electronic balancing circuits operate properly (unlike low-cost lead-acid battery chargers which deliver unfiltered dc). Output voltage can be factory adjusted to meet OEM requirements for various lithium-ion battery chemistries and voltages. These converter/chargers are designed for lithium ion batteries, that typically store 3-4 times the energy of a lead/acid battery within the same space, with less weight.
Typical 12-V lithium-ion batteries are composed of 4 cells, each with a voltage rating of 3.2V wired in series providing a total output of 12.8V. Lithium iron phosphate type cells are considered to be the safest and most common type used however, they must never be charged to a voltage over 4V and must never be discharged below 2V, or they will be damaged. Other cell chemistries require different voltage limits. These new chargers can accommodate the needs of each specific lithium chemistry.
Due to manufacturing inconsistencies each lithium ion cell is different (i.e. they will each charge and discharge at different rates). These cell differences make recharging lithium batteries fairly complex and requires that the battery manufacture must install electronic balancing circuits inside the battery to prevent overcharging a cell, or discharging too much. While these balancing circuits protect the cells, they can increase recharge times, depending on the mix of cells in each 12-volt battery pack. This increase in recharge time is especially apparent in higher voltage and or higher current battery packs. Lithium ion batteries also require battery chargers that can produce a higher voltage than provided by standard 12-volt or 24-volt lead/acid battery chargers. Trying to recharge a lithium ion battery with a standard lead/acid charger will result in a partially charged battery and may reduce battery life.