Want to modify battery packs for electric skateboards, electric toys, electric scooters, etc.?
If your answer is: yes. Then this article can help you better DIY lithium battery pack.

We have compiled the following 4 tips for reference.

1. The choice of battery: The choice of battery is often the key to DIY lithium battery packs.lithium-battery
The choice of lithium battery is mainly from two aspects of battery voltage and capacity. The battery voltage should be the same as the voltage of the motor, or slightly higher than the voltage of the motor. The capacity of the battery is in AH. When the voltage is the same, the capacity is larger and the volume is larger. For example, the working current of the motor is 10A and the voltage is 12V, that is, 10A*12V=120W. If you use a 12V/10AH battery, the motor can work for 1 hour. The rated working current of the 120W12V DC motor is about 10A, and the battery energy storage for 20 minutes at the maximum power of 120W is 40Wh. The battery pack needs a capacity of about 12V4Ah, and the lithium battery is a power battery. The recommended combination is a manganese-lithium polymer battery with a single-cell capacity of 4-5Ah, three in series, a working voltage of 3*3.7V=11.1V, and a battery weight of about 100-200g.

2. Battery processing

When you get the battery, it doesn't mean you can dispose of it immediately. It must be processed again before it can be used. (For power battery pack). The battery pack must be equipped with a matching protective plate!

The battery requires matching consistency, the more consistent the better, and the more stable. If the matching is inconsistent, there will be insufficient capacity, and in serious cases, the battery protection board will fail to detect and the battery pack will not work. How to deal with it?

(1) If possible, you can also filter by machine. If there is no machine, use the internal resistance tester to measure one by one, put the voltage, internal resistance, and capacity together, and let it stand for a period of time (7-15 days). After standing, test again. If it is still consistent, you can process it. up. This is also a physical method for judging the stability of the battery cell.

(2) Many friends will also ask if it can't be assembled and used directly? Of course, but if it does not match, the battery pack will follow the barrel theory and the capacity is limited to the lowest board. The worst cell in the battery pack is the upper limit. In layman's terms, the capacity of the battery pack will drop by 10-40%. More seriously, if there is a bad battery in the battery pack, the entire battery pack will not work. Inspection and maintenance work is cumbersome.

3. The choice of battery protection board

(1) Two electric wheels below 40A are sufficient. The specific choice should be judged according to your own motor power.

(2) The voltage should also be matched. 60V is mostly conventional. Need to distinguish between ternary and iron-lithium, as well as the number of strings.

(3) Try to use large capacity and low power, stable and durable. If it is a high-power small battery, be sure to calculate whether it supports the discharge rate.

(4) Try to choose a protection board with low protection voltage to give the battery a certain margin. For example: 4.25V protection is not as good as 4.2V~4.1V, because it will not allow the battery to reach 100% capacity.

4. Battery spot welding: the choice of tools is closely related to personal safety18650-spot-welder

In the spot welding process, safety is undoubtedly the key. Therefore, for DIY players, having a simple and easy-to-operate mini spot welder is undoubtedly the best choice.
The SQ-SW1 smart spot welder is powered by a battery, and the OLED display can display high and low voltage warnings. Adopt brand-new spot welding technology, intelligently switch automatic or manual working mode to meet different needs. It is a flexible and efficient welding tool.

Need a spot welder? You can buy it here:Buy spot welder

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