![]() ![]() With these constraints and the above values, one gets only one answer, t = 33Ah/10A = 3.3hr. Typically, a battery is considered "discharged" when it looses 1/3 of its capacity, therefore it only needs 1/3 of its capacity to be fully charged (range of operation). You also need to keep in mind that a battery is not supposed to be "fully" discharged. If you want a the battery to last a "long" time and no overheating, then the charging or discharging current must be kept at not more than 1/10 of the rated capacity. However, in the real/practical world, you have to take into consideration the heat generated in each process, the efficiency, the type of battery, the operating range, and other variables. In other words, you can have "any time" as long as when you multiply it by the current, you get 100 (the battery capacity). Or if delivering 100A, it would last 1 hour. 100 watts of solar panel rating generates about 400 watt-hours per day on average, so a 300 watt panel should charge the battery during a day. For example, 100 Ah battery delivering 1A, would last 100 hours. Assuming that the battery is a deep-cycle lead-acid depleted 50, then it needs 100Ah or 1200 watt-hours to recharge it. ![]() If the capacity is given in amp-hours and current in amps, time will be in hours (charging or discharging). In the ideal/theoretical case, the time would be t = capacity/current. But, a very useful % of total charge is reached in 1 hour. The CV stage typically takes 1.5 to 2 hours (depending on termination current% and other factors) so total charge time is about 40m +1.5 hours to 50 minutes +2 hours or Discharging occurs anytime you use the battery for power. To be safe, never discharge lower than 3.0V unless you know your cell's specification. When charged from "empty" at C/1 a LiIon cell achieves about 70% - 80% of full charge in 0.6 to 0.7 hours ~= 40 to 50 minutes. 18650 lithium-ion batteries are charged up to 4.2V and down to between 2V and 3V depending on the cell's specification for cut-off voltage. Higher % termination current = longer cycle life, lower charge time and slightly less capacity for the following discharge cycle. They are then charged at CV = constant voltage = 4.2V and the current falls under battery chemistry control.Ĭharge endpoint is reached when I_charge in CV mode falls to some preset % of Imax - typically 25%. LiIon's are charged at CC = constant current = <= max allowed current from 'empty' until charge voltage reaches 4.2V. This is usually C/1, sometimes C/2 and very occasionally 2C. LiIon / LiPo should not be charged at above manufacturers spec. The main reason to adding an answer to a 3+ year old question is to note that: H=Higher charge rates have lower energy efficiencies as resistive losses increase towards the end of charging.īelow LiIon and LiPo are interchangeable in this context. LiIon / LiPo have almost 100 current charge efficiency but energy charge efficiency depends on charge rate. Discharge rates are well enough covered here. ![]()
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