18650 rechargeable battery lithium 3.7v 3500mah

Technical points and precautions for converting 18650 rechargeable battery lithium 3.7v 3500mah of electric vehicles into lithium batteries

The battery on the battery car can be understood as a movable and dischargeable power source. The power source is ultimately used for other loads such as motors and bulbs on the car. The power source pays attention to parameters such as voltage, current and capacity. As long as the voltage is close and does not exceed the rated voltage of the load on the car, the lead-acid battery can be converted into a lithium battery. The larger the capacity, the longer the mileage.

1. When modifying, you must consider the volume and space issues. Under the same capacity, the volume of the lithium battery is only half of that of the lead-acid battery, so it can definitely be installed, but you must pay attention to some shape and packaging issues. After all, the space on the car is not necessarily in the same direction as the battery. You have to consider fixing it reliably to avoid vibration and falling. And if economic conditions permit, of course, you hope that the capacity of the modified lithium battery is as large as possible, so you need to make full use of the upper space and choose a battery with a reasonable shape for layout. If you replace the same capacity, because there is much remaining space, you need to find something to fill the extra space when replacing it to avoid the lithium battery shaking and falling off during driving.

2. When disassembling and assembling the battery, although the battery output is just two positive and negative wires, which is very simple, you should also remove them one by one, wrap the exposed wire ears with tape, and then mark them with ± marks. In this way, when you install them back, you can connect them one by one, positive to positive and negative to negative, to avoid connecting the positive and negative in reverse when you are confused, or accidentally short-circuiting the positive and negative poles of the positive and negative batteries, causing safety problems.

3. When buying lithium batteries, it is best to ask the merchant to match the same or similar plug terminals. If the plug shape is different, some may need to re-press the wire ears or weld, or even convert the wires. You must pay attention to the current size to choose the specifications. It is best to put a multimeter with DC, and re-measure the voltage when wiring to avoid reversing the positive and negative. Remember, the positive and negative poles must be placed separately, and do not perform operations such as grounding the negative pole.

4. If you change the battery and enlarge the motor and controller at the same time, you should consider whether the main circuit line should also be thickened. You can check the electrician's manual to see how many square wires can pass how many amperes of current. If the original car's wires are thin, this will also leave safety hazards, and the efficiency and power effect will be discounted.

5. When changing 18650 rechargeable battery lithium 3.7v 3500mah to lithium batteries, the charger must be changed to a special one for lithium batteries. 18650 rechargeable battery lithium 3.7v 3500mah have a large internal resistance. Generally, the output voltage of the charger should be higher, and many have pulse charging functions. In this way, the lithium battery may be overcharged during charging. Because there is a protection board to protect it, the charger output voltage setting will be abnormal during charging, and the lagging monomer may not be fully charged and cause damage. If the protection board happens to be broken, high-voltage charging can easily cause an explosion.

6. If conditions permit, you can consider changing the undervoltage and overvoltage protection range of the controller. The lead-acid battery monomer is 2 volts, and 6 of them form a 12-volt battery. The lower limit of discharge is generally controlled above 10.8 volts. The nominal voltage of a single ternary lithium battery is 3.7 volts, and the actual voltage of three batteries connected in series is only 11.1 volts. However, the lower limit of discharge can reach 9 volts. If four batteries are connected in series, the lower limit of discharge is 12 volts. If the threshold protection voltage of the lead-acid battery continues to be used, some of the electricity will not be released effectively, reducing the advantages of the lithium battery.

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