What is the capacity of 18650 battery?

As for small capacity UPS, in addition to the standard around 30 min.The battery matches outside quantity to extend battery backup time. Generally large capacity UPS has no standard battery, but according to the needs of the match.These need to choose the battery capacity, but generally cannot get correct battery capacity calculation.Reason is that if the discharge current of the battery is more than the threshold value stipulated discharge rate, it may appear nonlinear, which is to say, the discharge current and battery voltage no longer maintain linear relationship, so it needs to calculate and check the table or curve with the combination of methods to determine the battery capacity.

Using the constant current discharge curve to determine the battery capacity

Before the check curve, first calculate the discharge current value Id

Type of Id - discharge current (A);

S - UPS power rating (VA);

F - the load power factor, F 1 or less;

Eta - inverter efficiency, eta 1 or less;

K - load utilization coefficient;

Umin moments before - UPS power off the battery voltage (V).

Case 1: a 10 kva load power factor is 0.8, mains power request delay after 8 h.The user require the use of 100 ah battery, need how many?

Solution: choose according to the requirements of a nominal value is 15 kva UPS, inverter efficiency eta = 0.95 is known, 16 12 v batteries, dc voltage with load utilization coefficient k 1.

Often have this kind of circumstance, suppliers to reduce prices, improve competitiveness, without authorization, chose load utilization coefficient is small, and give a "according to", in the case of initial user puzzled, head start.To the user after the compatibilizing planted hidden dangers.Generally this load utilization coefficient k should be chosen by the users themselves.It is advisable to suppliers to choose 1.Calculated on general situation, the rated dc voltage should be

Un=12V×16=192V(2)

18650 is lithium ion batteries granddaddy of Japan's SONY company in order to save cost and set a standard of lithium ion battery model, including 18 said to 18 mm in diameter, 65 said length is 65 mm, 0 means for cylindrical batteries.General notebook with 18650 batteries usually capacity is 2200 mAh (mAh) can be interpreted as: 3.7 V voltage, 2200 ma (ma) current power supply, can be used for 1 hour (hour) capacity of the current times, count the result (mAh) also:

Learned to know the physical, W (watt, power unit) = V (V, voltage unit) * A (Ann, current unit), so, we can calculate 18650 x 2200 mAh batteries capacity of 3.7 V = 8.14 Wh, so they know three core battery capacity 8.14 * 3 = 24.42 Wh, four core battery capacity 8.14 x 4 = 32.56 Wh, six core battery capacity is 8.14 * 6 = 48.84 Wh.

The above three total capacity value is far difference between each other, especially between the Cdt and Cft is sent 1424 ah, on the UPS battery is a difference of 15 day!If section 100 ah battery meter by 800 yuan, 12000 yuan, now 15 kva UPS about 40000 yuan, this is about a third of the price of UPS.Particularly noteworthy is due to battery capacity difference, will confuse the user: exactly which capacity value right?Which one battery capacity value to meet the requirements?Battery capacity is small while prices to fall, but planted users suffer losses.

Above is just the difference between the capacity caused by some worry, because the battery capacity has not yet been finalized, which is to is wrong needs further analysis.Due to the battery discharge current increases when the discharge regularity is nonlinear, calculate alone is not the correct results.So still need to check discharge curve is shown in figure 1, it is Panasonic battery100 ah discharge curve, can be seen from figure 1, there are four different temperature of the discharge curve, from left to right, in order to 15 ℃ and 0 ℃, 25 ℃ and 40 ℃.As an example, just check a curve corresponding to 25 ℃.There are two types of check method: by the time check current method and the current time.

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