How To Choose Batteries For Mechanical Mods And Regulated Mods
- Time of issue:2020-04-30 14:08
How To Choose Batteries For Mechanical Mods And Regulated Mods
There are many types of batteries in the market today, so the choice of batteries has always been a headache for newbies. So which battery is suitable for your mods? Today I will share some tips about the battery selection.
Usually the 18650 battery is fully charged at 4.2V, while the stable voltage is 3.7V (there are some special lithium batteries are 3.2V, this article only focuses on the commonly used 3.7V lithium batteries). When using a mechanical mod, the voltage applied to the atomizer is the voltage of the battery itself. Unlike the regulated mod can adjust the output voltage.
Basic guide - battery specifications
There are two major specifications of battery, one is the capacity (mAh rating), and the other is the amps (continuous discharge rate). The capacity or mAh rating refers to how long a battery will last, and the amp rating or continuous discharge rate (CDR) refers to the available of maximum continuous discharge current of the battery. Because the larger the capacity, the higher the internal resistance of the battery, so the two are usually inversely proportional.
How to choose the battery for the mechanical mod
The principle of the mechanical mod is actually the battery container and the current conductor, which can directly exert the maximum output capacity of the battery, so the requirements on the battery are higher.
A. Use high-quality, brand name batteries
Regarding the mech mod, the most important thing is the safety. There are several reasons for mech mod accidents:
1. Inferior battery without pressure relief valve.
2. The maximum continuous discharge current is too low, and exceeds the standard value during use, resulting in excessive battery pressure, serious damage to the battery steel shell due to heat, and the internal material reacts with air to release a large amount of gas. When the pressure is large enough, the wall of the mech mod will be spread. In fact, this is still due to the lack of the pressure relief valve, the battery will not automatically stop working.
3. A broken battery causes short-circuit or form a circuit without passing through the switch after contact with the shaft. The atomizer will work automatically, and an accident may occur if it is not found for a long time.
4. Some structural defects or unreasonable design of the mechanical mod will also cause battery short circuit.
5. The electrode structure of the atomizer causes a short circuit in the battery. For example, the positive part of the power supply is flush or concave atomizer is used with a mechanical mod without a positive pole.
We can found that the basic cause of the accident is the battery. Therefore, please use the high quality brand name batteries.
B. Do not exceed the battery's max continuous discharge current
In addition to choosing a qualified battery, it is also necessary to pay attention to the continuous discharge current of the battery not to exceed the standard (that is, the issue of the atomizer resistance is too low and short circuit).
So what standard battery should we choose? Calculate it according to the standard Ohms law calculations at full charge voltage, i.e. voltage / resistance = current. For example:
if you use 0.2Ω, then it is 3.7 / 0.2 = 18.5A,
if you use 0.12Ω, then it is 3.7 / 0.12 = 30.8A.
Because 30A is a stable continuous discharge current, so it is also possible to reach 40A in a short time, but it will affect the battery life. And the increase of the internal resistance of the battery may cause safety hazards, so the resistance value is not recommended to be less than 0.12Ω.
And the power output of the mechanical mod is related to the resistance value, we use another formula to calculate, 3.7²/ resistance = power, then
resistance 0.2Ω represents (3.7 * 3.7) / 0.2=68.45W,
and 0.14Ωis (3.7*3.7) / 0.14=97.78W.
You can determine to use how much resistance according to your cloudy vapors need. Then you can choose the battery according to this resistance value.
Since the capacity is inversely proportional to the maximum continuous discharge current, if you don’t need large cloudy vapors, you can use a low-amps high-capacity battery.
C. Pay attention to the discharge performance of the battery
There is also an important reference for the battery - discharge performance curve graph. Through the curve of the voltage drop when the battery is discharged at different currents and the duration of the discharge, the discharge performance of the battery can be well reflected.
For example: if a battery can support 40A at the highest discharge, but the actual test that its voltage dropped from 4.2V to 3V in just 1 second under 40A, then the performance of this battery is obvious not good.
It is recommended to choose a battery that has a stable continuous discharge, and not too small capacity, so that you can guarantee the mod endurance while ensuring your taste.
How to choose battery for regulated mod
Regulated mods use circuitry and a processor to control power output from the batteries, monitor power settings, atomizer resistance and battery life with safety protections, so the requirements for the battery are lower than the mechanical mod. But it does not mean that any battery can be chosen at will.
So how do we choose the battery of the regulated mod? First of all, you need to know how much power you usually use, so that you can determine how much stable and continuous discharge current of the battery you need, and then use this data to select the battery capacity. So you can maximize the performance of the battery.
An important attention! Because on a regulated mod, there is a voltage regulator in between the battery and the atomizer, so the mod screen display the output amp load and voltage, not the amp load drawn from their batteries. Therefore, what you really want to know is the input of the board.
According to the Ohms law, P (watts) / V (cut off voltage) =I (amps)
Then, the amps = watts used / battery cutoff point / number of batteries / mod efficiency
Why use cutoff voltage? Because the battery voltage drops during use, the regulator will have to increase the amps drawn to keep him at set watts.
First, let’s use a single battery mod at 70W, guess the cutoff voltage 3.2V, 90% mod efficiency (some mods show the efficiency on their datasheet).
So you only need a battery with 25A continuous discharge, even at cut off where amp load is highest.
For the dual batteries, it is divided into the series and parallel forms:
the voltage = the sum of all battery voltages
the current = the current of each battery
the voltage = a single battery voltage
The current = the sum of battery currents
We can find that we don’t need to care the batteries in mod are in series or in parallel, because the calculated result is the same.
In the case of 70W again, mod with dual cells:
70/3.2/2/90%=12.15 amps per cell
That means a single 20A battery is enough.
If the discharge of the battery is lower than the calculation result, the battery power is not durable, and the mod will remind low battery voltage when the power display is still one third, and the set output power cannot be reached.
Tip: Even if your regulated mod has safety protections, do not use a broken battery to avoid danger.
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