How Harley Scooter SLA Battery 60v 20Ah Change to Lithium ion Battery?
more and more people know lithium ion battery could give much power and lengthen total navagation kilometer(km), so they want to DIY his/her harley scooter SAL battery replaced with lithium ion battery. if you have same interest, could take reference as below:
1. Selection of Lithium Batteries
It is better to choose polymer lithium batteries than lithium particle batteries. Because lithium particle batteries are prone to explosion, combustion and debris splash when they are overcharged, overdischarged or overheated, and they occur at the same time in an instant, which makes it difficult to prevent them. When polymer lithium batteries are over-charged, over-discharged or over-heated, the aluminium-plastic membrane bulges in the star shell: the inner plate of the battery is separated from the plastic membrane separator,'Because there is no electrolyte in the battery, the internal resistance of the battery increases rapidly, the capacity is lost, the battery fails automatically, and the accident terminates itself, so explosion is not easy to occur.
2. select capacity
Choose large capacity lithium batteries as far as possible. For example, the original battery capacity lOAh, when choosing lithium batteries, it is best to use 5Ah block lithium batteries in parallel. The capacity of the assembled lithium battery shall not be less than that of the original vehicle battery.
3. select new and old
Choose new lithium batteries of the same type and batch produced by the same factory as far as possible. These new batteries have good consistency, safe use and long service life.
4. select protection circuit
When lithium batteries are used to refit electric vehicles, a multiple protection circuit combining single battery protection with overall battery protection should be adopted.
(1) Each single battery shall be equipped with its own protective plate, and then connected in series to form a battery suited for the voltage and capacity of electric vehicles. Each protective plate shall have at least the following functions:
1) Over-current protection: When the current reaches 15C, the power is automatically cut off. Among them, C is battery capacity.
2) Overcharge protection: When the charging voltage reaches 4.2V, the power will be cut off automatically.
3) Over-discharge protection: When the discharge voltage reaches 3.ov, the discharge will stop automatically.
(2) The lithium turtle pool pack assembled by single lithium batteries for general protection needs to be equipped with general protection circuit, including multiple protection such as over-current, over-charge, over-discharge and over-temperature.
An example is given to illustrate the method of installing overall protection circuit for a group of 60V/IOA lithium battery packs.
1) Current protection
The picture above shows the overcurrent protection device. E is 60V/1OAh lithium battery pack; BX is 20A insurance; J is relay (replaced by YE-KDC-A04:8 color TV switch): C is dry reed tube; LlR is current limiting resistance; C is energy storage capacitor; D is diode; TK is a temperature switch, operating temperature 45 C, M is electric vehicle motor.
When the JK is closed, the. M runs normally. E charges to C through D, and the electric vehicle runs normally. When I (> 14A), the strong magnetic field emitted by L closes the contacts in G. The stored electric energy in C is absorbed by the internal resistance R and R of J winding. J makes Jl (release, cut off the circuit. E) stop supplying power to M. This ensures that E is not burnt down by high current.
The relationship between the action current I of the protector and the number N of L turns of the sampling coil is shown in the attached table.
The protection device has the following advantages: 1. The sampling circuit coil L is a 1.2mm enameled wire with a length of llcm, and its energy consumption tends to be 0; 2. The protection action is sensitive and crisp.
2) When over-voltage protection is used to charge 60V lithium battery pack, when the voltage reaches 42V, the charging power supply must be cut off automatically. The circuit shown below meets this requirement. Three diodes Dl, D2 and D3 (1N5408x3) are connected in series at the positive output terminal of SP-70A charger in the car (second stage). When charging 60V lithium battery pack E at the beginning (first stage), the voltage at point A is 71.04V.D1~D3, and the up voltage drops to 2.6V. When charging 60V lithium battery pack E at constant current of 1.5A, the voltage drops to 2.6V. With the passage of time, the voltage of E keeps rising. When the voltage rises to 66.88V, SP-70A moves to the second stage of charging. The output voltage of point A suddenly changes to + 66.72V. O.lV.DI~D3 is in reverse bias lower than point B. The charging current is automatically blocked and charging ends.
3) The rated discharge termination voltage of overdischarge protection single lithium battery is 3.OV. For electric vehicles, the discharge termination voltage should be increased to 5.04V. 60V lithium battery pack, discharge termination voltage set to 315V has the following advantages: 1. It is compatible with the original vehicle lead battery discharge termination voltage 50.4V, so that the original vehicle controller can be applied to both lead-lithium batteries at the same time, which reduces the cost and improves the reliability; 2. The lithium electric discharge depth becomes shallow and benefits its life.
Therefore, the 50.4V over-discharge protector in the original controller is decided to be used as the over-discharge protector of lithium battery pack. When the lithium battery discharges to 50.4V, the protector acts (green undervoltage lamp is on). The power supply to motor M of electric vehicle is automatically cut off. This protects the lithium battery pack from damage due to overdischarge.
What SINOLI Battery can do for you?
SINOLI battery is a professional lithium ion battery manufacturer. it offers good quality battery and protective circuit board, which will be test before assembley so as to make sure quality is under guranttee.