What is the capacity of the 12V maximum battery?

There are two kinds of batteries for electric vehicles. They are lead-acid battery and lithium battery. Lead-acid battery capacity are 12 ah, 20ah, 20ah, 24ah! Lithium battery capacity is not necessary because lithium battery can be any combination for large capacity battery, such as 48 v40ah, 72 v80ah and so on!

Battery capacity is one of the important performance index to measure the battery performance and it says under certain conditions (discharge rate, temperature, voltage, etc.) out of battery power (or JS - 150 - d discharge tests), namely the capacity of the battery, usually, ampere hour as the unit (hereinafter referred to as expressed in a. H, 1 a. H = 3600 c).

Battery capacity according to different conditions as the actual capacity, capacity and nominal capacity, battery capacity calculation formula of C = C ∫ t0It1dt (in the t0 the t1 time on current I integral), battery is negative.

Battery capacity according to different conditions can be divided into the actual capacity, theoretical capacity and rated capacity.

Under a certain discharge rate from 25 ℃ to discharge voltage of the minimum capacity is a design and production rule of battery capacity, this is called a rated capacity of the discharge rate of RH.

Square lithium ion batteries

Square lithium ion battery

Battery capacity with AH commonly (ampere hour), another is the CELL plate (unit) a few watts (W).(W/CELL)

1. Ah (ampere hour) calculation, the discharge current (constant current) I (discharge time (hours) T. For example, 7 ah battery if continuous discharge current of 0.35 A, so time is 20 hours continuously.

2. Recharge time to 15 hours as a standard, 1/10 of the charging current of battery capacity, quick charging will reduce battery life.

Battery capacity refers to the size of the battery storage capacity. Battery capacity is the unit of "mAh", Chinese name is ma (in measuring large capacity batteries such as lead-acid batteries, for convenience, generally by "Ah", Chinese name is, 1 Ah = 1000 mAh).If the battery rated capacity is 1300 mAh, the discharge current of 130 ma to battery, the battery can last work for 10 hours (1300 mAh / 130 ma = 10 h);If the discharge current is 1300 ma, the power supply time is only 1 hour (the actual working hours due to the actual capacity of the individual difference of the battery have some differences).This is the ideal situation analysis, digital device when the actual work current could not remain constant in a numerical (digital cameras, for example, working current, flash and other parts of the LCD display larger changes in the open or closed), so the battery to the power supply time only on a device is a about value, and this value is only estimated by actual operating experience.

We usually speak when battery capacity is based on Ann for the unit, which is based on the established a battery.

Like we said the cell phone battery capacity is much; How much is the battery car battery capacity, are respectively according to different batteries. In view of the battery voltage that have been confirmed, without taking into account the actual voltage, just say when Ann can represent the battery capacity.

For different voltage of battery, however, we cannot simply use Ann representative capacity, such as a piece of 12 v20ah battery, a 15 v20ah battery, even if is 20 ah, the same power supply load, the equipment can work normally, but the duration is different, so the size should be the standard in order to work for the unit.

For example, a device can support the 12 v and 24 v can also support, with a 12 v (20 ah) batteries, can provide an hour, then use two pieces of series will be 24 v (20 ah) including Ann did not increase, but the duration of a times, so cells hold capacity should be considered at this time for the work, not only consider to Ann.

W (work) = P (power) * T (time) = I (current) * U (voltage) * T (time)

So discuss battery capacity have some practical significance, must seek truth from facts, otherwise may have a cell phone battery is bigger than battery car battery capacity, this is obviously not scientific.

To constant current constant voltage charge a battery, and then to constant exile, release how much power is the capacity of the battery, battery, nickel metal hydride batteries, etc., but not a lithium battery, it has a minimum discharge voltage, the discharge voltage not less than 2.75 V, usually in 3.0 V voltage to lower limit protection. Such as lithium battery capacity is 1000 mAh, the charge and discharge current is 1000 ma, inside the battery voltage of 4.2 V to 3.0 V, release the capacity is the most real capacity of the battery.

Battery capacity is an important indicator to measure the performance of the battery. Ann is commonly used in the comings. Discharge time (hours) and the floorboard of the discharge current (amps), namely capacity = x discharge current discharge time. The actual capacity of the battery, it depends on the active substances in the cells and the utilization of active material. The more amount of active material is, the higher the utilization of active material, the capacity of the battery. Vice volume is smaller, there are many factors which can influence the battery capacity, commonly has the following kinds:

(1) The discharge rate's impact on battery capacity

Lead battery capacity to reduce with the increase of discharge ratio, that means the larger the discharge current, calculate the content of the battery. A 10 ah battery, for example, use 5 a discharge can put 2 hours, or 5 x 2 = 10; In 10 a discharge can only release 47.4 minutes, 0.79 hours. Its capacity is only 10 * 0.79 = 0.79 ampere hour. So for a given battery without rate to devolve electricity at the same time, there will be a different capacity. We must know about your capacity when discharge rate or rate. Simple speak is how current discharge.

(2) the influence of temperature on the battery capacity

Temperature had a greater influence on the capacity of lead-acid battery, generally with the temperature decrease, reduced capacity, capacity and temperature relations such as:

Ct1 + k = Ct2/1 (t1, t2) t1t2 were the temperature of the electrolyte, k for the temperature coefficient of capacity, Ct1 temperature for t1 capacity (Ah), temperature for t2 Ct2 is the capacity (Ah) in battery production standard, typically a rated temperature for normal temperature, such as t1 as the actual temperature, t2 as the standard temperature, (general is 25 degrees Celsius) negative plate is affected by low temperature sensitive than positive plate. When the temperature falls, electrolyte viscosity increases, ion by larger resistance, diffusion ability to drop, electrolyte resistance also increases, the electrochemical reaction resistance increased, part of the normal transformation of lead sulfate. Charge to accept ability to drop, as a result, battery capacity decline.

(3) Terminate the influence of the voltage of battery capacity

When the battery discharge to a certain voltage, voltage drops sharply, which is actually gained by the energy is very small, if long-term deep discharge, the damage to the battery is quite large. So must terminate discharge at a voltage, the globe discharge voltage discharging termination voltage. Set the discharging termination voltage, is of great significance to prolong the service life of the battery. Generally we repair of electric vehicle batteries, electric motorcycle battery discharging termination voltage of 1.75 volts per cell, which means that 12-volt battery is 6, the discharging termination voltage is 6 x 1.75 = 10.5 v. [2]

(4) Plate geometry size effect on the battery capacity

When the amount of active material must be direct contact with the electrolyte plate geometry area, and the battery capacity increases, so the plate geometry size has the impact on the battery capacity cannot be ignored.

(1) Plate thickness effect on the capacity

The quantity of active substance must, battery capacity with the increase of the thickness of the plate, plate is thicker, sulfuric acid and active material interface is the less, the lower the utilization of active material, the smaller the battery capacity.

(2) The plate height effect on capacity

In the battery, the utilization of active material of plate of fluctuation two parts there is a bigger difference, the experiment proves, the early discharge, the upper plate is 2 times higher than the lower current density is about ~ ~ 2.5 times, the difference with the passage of discharging gradually reduce, but the upper than the lower current density.

(3) Plate area of the impact on the capacity

The quantity of active substance is certain. The larger plate geometry size, the higher the utilization of active material, and the greater the capacity of the battery is. The battery shell is the same, under the condition of constant quality of active matter, use thin plate to increase plate number, which is also to increase the area of effective reaction plate, thus improve the utilization of active material, and increase the capacity of the battery.

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