1. What accessories come with the batteries ?
2. How to prolong the lifetime of Li-ion batteries ?
3. How to store Li-ion Batteries ?
4. What can potentially damage batteries ?
5. How much current can I draw from my battery pack ?
6. How many cells do I need to have for my application ?
7. What cell size is most suitable for my application ?
8. Why is my TSL charger acting strange after a full charge ?
9. Can I adjust the output voltage of my charger ?


1. What accessories come with the batteries ?

Bolts and copper connectors are provided with battery purchases with no additional cost.

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2. How to prolong the lifetime of Li-ion batteries ?

Li-ion batteries must be maintained within a certain voltage range, 2.50 - 4.25V, at all times. We recommend our users to control cell voltage between 2.80 – 3.80V during application. Two things have to be avoided:

• over charging (> 4.25V per cell)
• over discharging (< 2.50V per cell)

To prevent over-charging, users are recommended to use our matching chargers: TSL series for motorcycle, scooter and bike applications, and EPS series chargers for car applications. Our chargers are specially design to prevent over-charging condition. To prevent over-discharge condition, users are recommended to set proper low voltage limits in motor controller. Our batteries have no memory effect. You do not have to fully discharge the battery before recharging. In fact, fully discharging will cause capacity loss. We recommend users to charge as often as they wish. For car application, we also strongly recommend users to implement BMS (Battery Management System), which will monitor voltage of each cell, current and temperatures of the battery pack. BMS will provide over-voltage, under-voltage, over-current and over-temperature alarms, which can be fed to charger and motor controllers to trigger proper actions. Cell balancing capability is a very beneficial feature to bring the cells within a pack more closed matched. We currently do not have cell balancers available. We are exploring in this direction. We welcome collaboration and partnership leading to most suitable solution in this area. We only recommend putting cells in series during application, never in parallel. This ensures all cells are having the same charge and discharge rate (same current).

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3. How to store Li-ion Batteries ?

Our batteries have characteristics of very low self leakage rate, ~ 3% per month, which allows batteries to be stored over extended period of time. Batteries are to be charged at 40-60% full before long term storage. Batteries must be stored in cool temperature environment. Avoid batteries being exposed to summer heat. Users are recommended to check cell voltages periodically, eg. every 2 weeks, to ensure proper voltage level. If cell voltage drops close to 3.0V or under 3.0V, battery needs to be recharged.

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4. What can potentially damage batteries ?

• Not using a proper charger or no protection during charging, which lead to an over-charging condition.
• Not monitoring or properly control low voltage limit during discharging, which lead to over-discharge condition.
• Drawing extreme high current (>3C) over extended period of time (>20seconds).
• Put batteries in parallel, which leads to unbalanced charging and discharging condition
• Mixing batteries with different characteristics, voltage range, capacity, internal resistance, age and etc, which leads to uneven loading across batteries and potential over-charge and over-discharge conditions.
• Not operating and storing batteries in the desired temperature range

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5. How much current can I draw from my battery pack ?

Cell voltage will drop with increased current draw, or voltage sag can be observed during high current draw. Voltage sag may become significant when current draw is over 2C. We recommend pulsed current draw to be limited to 3C, and continuous current draw to be limited to 2C during application. Pulsed current draw must be limited under 20 seconds. Extended period of high current draw (over 3C) will shorten the lifetime of batteries, and may even damage the batteries.

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6. How many cells do I need to have for my application ?

Each cell has nominal voltage of 3.2V (2.5V min and 4.25V max). Based on your electric motor voltage demand, you can decide how many batteries you need. If you have a 144V system, the number of batteries you need is 144V / 3.2V = 45 cells.

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7. What cell size is most suitable for my application ?

After you decide how many cells you need, now you need to decide what cells you want to use for your application. You need to choose how much energy capacity you need in each cell. This depends on how much range you want with you vehicle and how much energy consumption per mile of your vehicle is. Your driving habit strongly affects energy consumption rate (kWh/mile). Range drops with increasing speed. Under Technical Reference session of this website you can find range vs. speed curves under link EV Application Calculation. A typical small sedan will consume about 0.25 kWh energy per mile. Based on your desired conditions for your application (vehicle weight, average speed, range, etc.), you can decide how much energy you need in your pack (kWh), which will then decide the capacity of your battery choice. For example, if you need 28.8kWh capacity and you have decided on 45 cells based on the voltage range of your motor, 28800 kWh / 45 cells / 3.2V per cell = 200Ah. You need cells with 200Ah capacity.

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8. Why is my TSL charger acting strange after a full charge ?

TSL charger has 3-step charging program: constant current, constant voltage and pulse charging. At the final stage, you will notice that the charger is on for a minute and off a minute and repeating. This is normal because it is in the pulse charging mode. The pulse charging step helps to bring the cells within a pack more closely matched in terms of charging state and voltage.

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9. Can I adjust the output voltage of my charger ?

TSL series chargers have fixed configuration. Each type of charger is designed for a certain pack size, like 8 cells, 12 cells, etc. EPS chargers have adjustable current and voltage ranges. EPS chargers are designed for maximum pack size of 40 cells, 50 cells, and up to 100cells. For example, if you have a 55 cell pack, you may buy a 60 cell charger (max 240V output) and adjust output voltage level down according for 55 cell pack (adjust to 220V output).

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