Cymbet Rechargeable Battery & Energy Storage Device
The following questions are commonly asked. If the answer provided below is not answered satisfactorily, please contact Cymbet directly.
| Q: |
May I use a constant current source to charge the battery? |
| A: |
Yes, however it must be followed by a constant voltage mode and in both modes the voltage must not exceed the recommended charging voltage. See AN-1002 for recommended charge circuits and charging guidelines. |
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| Q: |
Can I use a standard Li-ion battery charger? |
| A: |
Yes; however, the battery charging current will be very low and the reverse leakage current must be kept low in order to prevent the battery from discharging through the charge circuit. |
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| Q: |
How will I know when the rechargeable battery is fully charged? |
| A: |
Either by time or current. The rechargeable battery are typically fully charged in about one hour; as the battery becomes fully charged, the current will decay to less than about 250 nA for the CBC012 and less than about 1 µA for the CBC050. |
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| Q: |
What happens if I charge the rechargeable battery before it has been soldered to a board? |
| A: |
The battery performance will be degraded and, if soldered while in a partially or fully charged state, might be destroyed. See AN-1001 . |
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| Q: |
What if I short-circuit the rechargeable battery or discharge it to zero volts slowly? |
| A: |
The battery cycle life will be reduced from its rated value. See AN-1002 . |
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| Q: |
What happens if I apply a voltage higher than the recommended charging voltage to the rechargeable battery? |
| A: |
The battery will likely be destroyed. |
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| Q: |
Do I need to use a safety circuit to prevent overheating or short-circuiting of the rechargeable battery? |
| A: |
No; however, discharging the battery to less than 3V will affect the cycle life of the battery. See AN-1002 . |
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| Q: |
What happens if the cell is short-circuited? Will it explode or leak harmful chemicals? |
| A: |
No. There are no harmful chemicals to leak and the battery will not explode. |
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| Q: |
Do I need to use a constant current followed by constant voltage charger? |
| A: |
No, although that charge method is permissible. A constant voltage charge method is acceptable. See AN-1002 .
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| Q: |
What types of protection circuits are required? |
| A: |
It is necessary to limit the battery charge voltage to no more than the recommended charge voltage. It is also important that external power supplies are not connected to the battery terminals except in accordance with Cymbet’s battery charging guidelines. See AN-1002. |
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| Q: |
How long will the cell hold a charge? |
| A: |
The self-discharge of the cell is a function of several parameters, including temperature. For the self-discharge specifications, see the product data sheets http://www.cymbet.com/content/products.asp .
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| Q: |
What happens if the cell is left in a discharged state for a long period of time? |
| A: |
Leaving the cell in a discharged state is not detrimental to the cell performance. |
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| Q: |
What happens if the cell is charged indefinitely? |
| A: |
Charging the cell indefinitely is not harmful to it. |
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| Q: |
What is the cell impedance? |
| A: |
The cell impedance is determined by a number of factors, including the surface area of the cell. For specific specifications of cell impedance, see the product data sheets at: http://www.cymbet.com/content/products.asp . |
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| Q: |
Can the cell be solder reflowed? Lead free? |
| A: |
Yes, the cells are tolerant to the lead-free 260°C reflow soldering profile. |
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| Q: |
What is the nominal voltage of the cell? |
| A: |
The nominal output voltage of the cell is 3.8V; at approximately 3.0V, the charge on the cell is nearly fully depleted at low discharge currents. See the product data sheets at http://www.cymbet.com/content/products.asp for typical discharge profiles. |
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| Q: |
Are the Cymbet rechargeable batteries sensitive to electrostatic discharge (ESD)? |
| A: |
Yes. Prior to charging the batteries, they are sensitive to ESD and should be handled accordingly. See AN-1001. |
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