How do you calculate lead-acid battery capacity and discharge?

Electric vehicle batteries currently include lead-acid batteries and lithium batteries. The lead-acid battery has a capacity of 12AH, 14AH, 20AH and 24AH. Lithium battery capacity is variable, because lithium battery can be any combination of large capacity batteries such as 48V40Ah, 72V80Ah and so on.

The capacity of electric vehicle battery indicates how much electric energy is stored in the battery, that is, after the battery is fully charged, the electric vehicle battery is discharged continuously with a certain battery value, starting from the discharge to the terminal voltage drop to the specified discharge termination voltage, the product value of discharge current and time. The unit of capacity of electric vehicle battery is ampere • hour, usually expressed as "Ah". Electric bicycle battery fully charged, the temperature of (25 + 2) ℃ environment let stand 1 ~ 4 h, and then to 1/2 rated capacity of the battery (2 hours) of constant current discharge to the monomer accumulator (A) the average voltage of 1.6 V (6 V battery is 4.8 V, 12 V) 9.6 is terminated, record the discharge time. New electric car battery in three tests, discharge time is greater than 120min on one of the qualified. The actual electric vehicle discharge current multiplied by the actual discharge hours is the actual capacity of the battery.

The size of the electric vehicle battery capacity depends on the electrochemical reaction of the active material and electrolyte quality. Plate manufacturing process, geometry size and the temperature of battery when using the measured actual capacity may also be affected. Plate piece number, the more the greater the relative area, the more active substance involved in chemical reactions, the greater the electric car battery; When using the higher the temperature, battery electrolyte to plate strong penetration ability, participate in the depth of the chemical reaction of the active material is more deep, the greater the electric car battery.

Commonly used valve control lead-acid battery electric vehicle there are mainly six - DZM - 10 and 6 - DZM - 20 two standard specifications, 6 here refers to the battery inside is composed of six cluster series, the former 2 hr capacity of 10 ampere hour (Ah), the latter 2 hr capacity of 20 Ah, some manufacturers also use 12 v10ah / 2 hr and 12 v20ah / 2 hr identity. In order to adapt to more design, after adjusting the battery plate shape, thickness, quantity and the proportion of the electrolyte concentration, dosage of active substances, such as technology, also has such as 6 - DZM - 7, 6 -, 6 - DZMDZM - 12-17, 18 June - DZM -, 6 - DZM - 24 models, etc.

1, "MAH" is the unit of battery capacity. The Chinese name is called MAH (in measuring large capacity batteries such as lead-acid batteries, for convenience, generally by "Ah", Chinese name is).

1, MAH = 0.001 amperes * 3600 seconds = 3.6 ampere s = 3.6 coulomb

2, the coulomb's power unit, the coulomb is not a basic unit of international system of units, but the international system of units derived units.1 coulomb = 1 amp, seconds.

Transport within 1 s 1 a current of electricity, which is 1 c = 1 a. s.

3, the electrical power calculation formula: P = UI.P is the unit of watts W; In the pure resistor in the circuit, according to the ohm's law in P = U = IR can also get the UI: P = I = U) (U * * IR/R

A, the most direct algorithm:

1, the first to get the current electrical equipment

2, battery capacity to be divided by the current results of electrical equipment is the length can be used

Such as:

A 3000 MAH, the rated voltage of 5 v battery to a 2.5W power consumption, voltage of 5 v power supply electrical equipment, its theory of hours used for:

I=P/U=>2.5w/5v=>0.5A=>500MA

3000 MAH, the current is 3000 ma can one hour,

3000/500 = 6 hours

Second, through the charge coulomb algorithm

C = IS = > 3 a * 3600 s = > 10800 C coulomb (charge)

10800 c * 5 v = 54000 w power

54000w/2.5w=21600/3600s=6h

The algorithm of UPS backup time after 2010-03-25

UPS battery discharge time calculation method

1) Calculate the biggest battery discharge current value:

I biggest = P Cos ф/ (eta critical * * E N) note: P - the nominal output power UPS power supply

Cos ф - UPS power output of the power factor (UPS generally 0.8)

Eta to EPS inverter efficiency, average of 0.88 ~ 0.94 (the actual calculation can take 0.9)

E critical - critical discharge voltage of the battery (The 12 v battery About 10.5 V, 2V battery is about 1.7 V)

N -the number of cells in each group

2) According to the selected battery backup time, find out the battery discharge rate value C, then according to:

The nominal capacity of the battery pack = I most C/C time and discharge rate

15 minutes 30 minutes 60 minutes, 90 minutes, 120 minutes, 180 minutes 1.98 C0.92 C0.61 C0.5 C0.42 C0.29 C

3) Such as 400 KVA time delay for 15 minutes

Battery rated power the maximum discharge current of 1058 a = 400000VA x 0.8 present each section efficiency (0.9 * 32 * 10.5 V batteries discharge voltage)

The nominal capacity of the battery pack = 1058 a present 1.98 C = 534.3 AH

The total capacity of the battery pack = 534.3 AH * section 32 * 12 v = 205171.2 AH so configuration section 12 v150ah32 section 4

Definition: the electrode is mainly composed of lead and its oxide, the electrolyte is a battery of the sulfuric acid solution. English: Lead – acid battery. Discharge condition, the positive main ingredients for lead dioxide, negative main composition as the lead; Charging status, the main components are all lead sulfate is negative, divided into exhaust type battery and maintenance-free lead-acid batteries.

Battery is mainly composed of tubular positive plate and negative plate, electrolyte, separator, battery case, battery cover, a column, filler cap, etc. Exhaust type of battery is made up of lead and lead oxide electrodes. Electrolyte is sulfuric acid aqueous solution. The main advantage is that the voltage stability, the price is cheap; Shortcoming is lower than can (that is, the storage battery power) per kilogram, short service life and maintenance frequency. Old-fashioned common battery life in 2 years, and to periodically check the height of the electrolyte and add distilled water. But with the development of science and technology, the life of the lead-acid battery maintenance is become more and more simple.

Lead-acid battery is marked by the top have to unscrew the plastic sealed cover, with the air vent. The filler cap is used for filling water, electrolyte and emissions. According to the theory, each time the lead-acid battery need maintenance check the electrolyte density and liquid level height, if there is a lack of need to add distilled water. However, as the battery manufacture technology upgrade, lead-acid battery development for lead-acid maintenance-free battery and colloid and maintenance-free batteries, lead-acid battery to add electrolyte or use distilled water. Mainly using the positive produce oxygen can be in negative oxygen absorption to circulation, can prevent the water cut. Lead-acid battery is mostly used in tractors, tricycles, motor starting, etc., and maintenance-free lead-acid battery application is wider, including uninterruptible power supply, electric power, electric bicycle batteries, etc. Lead-acid battery according to the need of application can be divided into constant exile electric (such as uninterruptible power supply) and instantaneous discharge (such as automobile starting batteries).

When discharging, the concentration of sulfuric acid solution will continue to decrease. When the density of solution drops to 1.18g/ml, it shall stop using for charging.

Charging: 2 PBSO? +2H?O = PBO?+ PB + 2 H?SO?(cell)

Lead battery

Lead battery (4)

Discharge: PBO?+ PB + 2 H?SO?= 2 PBSO?+ 2H?O (battery)

Anode: PBSO?+ 2H?O - 2 e ‐ = = = PBO?+ 4 h ﹢ + SO?2 ‐

Cathode: PBSO?+ 2 e ‐ = = = PB + SO?2 ‐

Negative: PB + SO?2 ‐ - 2 e = = = PBSO?

The positive: PBO?+ 4 h ﹢ + SO42 ‐ ‐ + 2 e = = = PBSO?+ 2 H?O

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