#Coffeecup web form builder 2.5 publish on own site full#

Table 2: Typical charge characteristics of lithium-ionĪdding full saturation at the set voltage boosts the capacity by about 10 percent but adds stress due to high voltage.

#Coffeecup web form builder 2.5 publish on own site how to#

(See also BU-808: How to Prolong Lithium-based Batteries) T able 2 illustrates the estimated capacities when charged to different voltage thresholds with and without saturation charge. State-of-charge (SoC) at this point is about 85 percent, a level that may be sufficient for many users.Ĭertain industrial chargers set the charge voltage threshold lower on purpose to prolong battery life. “Ready” appears when the battery reaches the voltage threshold at Stage 1. Some lower-cost consumer chargers may use the simplified “charge-and-run” method that charges a lithium-ion battery in one hour or less without going to the Stage 2 saturation charge. Chargers for consumer products go for maximum capacity and cannot be adjusted extended service life is perceived less important. Choosing a lower voltage threshold or eliminating the saturation charge altogether, prolongs battery life but this reduces the runtime. In fact, it is better not to fully charge because a high voltage stresses the battery. Li-ion does not need to be fully charged as is the case with lead acid, nor is it desirable to do so. A high current charge will, however, quickly fill the battery to about 70 percent. With higher current, Stage 1 is shorter but the saturation during Stage 2 will take longer. Although the battery reaches the voltage peak quicker, the saturation charge will take longer accordingly. Increasing the charge current does not hasten the full-charge state by much. Elevated self-discharge might be the cause of this condition.

A battery is also considered fully charged if the current levels off and cannot go down further. Discontinue using the battery or charger if the temperature rises more than 10✬ (18✯) under moderate charging speeds.įull charge occurs when the battery reaches the voltage threshold and the current drops to 3 percent of the rated current. This could be due to the protection circuit and/or elevated internal resistance. Some Li-ion packs may experience a temperature rise of about 5✬ (9✯) when reaching full charge. Charge efficiency is about 99 percent and the cell remains cool during charge. Manufacturers of these cells recommend charging at 0.8C or less to prolong battery life however, most Power Cells can take a higher charge C-rate with little stress. The advised charge rate of an Energy Cell is between 0.5C and 1C the complete charge time is about 2–3 hours. In lieu of trickle charge, some chargers apply a topping charge when the voltage drops. Li-ion is fully charged when the current drops to a set level. Full charge is reached when the current decreases to between 3 and 5 percent of the Ah rating.įigure 1: Charge stages of lithium-ion Protection circuits built into the pack do not allow exceeding the set voltage.įigure 1 shows the voltage and current signature as lithium-ion passes through the stages for constant current and topping charge. Boosting the voltage increases capacity, but going beyond specification stresses the battery and compromises safety. Some nickel-based varieties charge to 4.10V/cell high capacity Li-ion may go to 4.30V/cell and higher. Li-ion with the traditional cathode materials of cobalt, nickel, manganese and aluminum typically charge to 4.20V/cell. Li-ion is a “clean” system and only takes what it can absorb. The so-called miracle charger that promises to prolong battery life and gain extra capacity with pulses and other gimmicks does not exist. While lead acid offers some flexibility in terms of voltage cut off, manufacturers of Li-ion cells are very strict on the correct setting because Li-ion cannot accept overcharge. The differences with Li-ion lie in a higher voltage per cell, tighter voltage tolerances and the absence of trickle or float charge at full charge. The Li ion charger is a voltage-limiting device that has similarities to the lead acid system. (See BU-808b: What causes Li-ion to die?) They blame capacity fade on ions getting trapped, but as with all battery systems, internal corrosion and other degenerative effects also known as parasitic reactions on the electrolyte and electrodes still play a role. This claim carries merits but if the scientists were totally right, then the battery would live forever.

Battery scientists talk about energies flowing in and out of the battery as part of ion movement between anode and cathode. Charging and discharging batteries is a chemical reaction, but Li-ion is claimed to be the exception.