Charging an A123 battery?
04-19-2010, 11:35 AM
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Charging an A123 battery?
Hello all,
I just got a couple of A123 batteries to use as Rx Packs. My charger, a Venom - Pro, which seems to have very simular programing as many of the other chargers, says it has the capability to charge Li-ion/Polymer/LIFE batteries, however I can't seem to figure out what settings to use. I understand that I need to charge it to 6.6v, but should it be on the lipo setting? Or what?
Thanks in advance,
I just got a couple of A123 batteries to use as Rx Packs. My charger, a Venom - Pro, which seems to have very simular programing as many of the other chargers, says it has the capability to charge Li-ion/Polymer/LIFE batteries, however I can't seem to figure out what settings to use. I understand that I need to charge it to 6.6v, but should it be on the lipo setting? Or what?
Thanks in advance,
04-19-2010, 12:03 PM
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RE: Charging an A123 battery?
I guess that's my problem: I can't find the Life setting. The battery types cycle through Lipo, Nimh, Nicd, and PB, however the manual and box states it charges Life batteries.
Is the Life setting in a sub menu somewhere?
Thanks,
Is the Life setting in a sub menu somewhere?
Thanks,
04-19-2010, 06:15 PM
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RE: Charging an A123 battery?
OK, now for yet another question:
So, for the first charge I charded it at 2c so it being an 1100 mah battery I set it up for 2.2amps. My thought process was that it should take no longer than 1/2hr. to charge a completely depleted battery. This charge took 42 minutes and put only 340 mah back in.
Does this sound normal?
Thanks,
So, for the first charge I charded it at 2c so it being an 1100 mah battery I set it up for 2.2amps. My thought process was that it should take no longer than 1/2hr. to charge a completely depleted battery. This charge took 42 minutes and put only 340 mah back in.
Does this sound normal?
Thanks,
04-19-2010, 10:19 PM
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RE: Charging an A123 battery?
A123 (and other lithium chemistries) do not charge at a constant rate. Instead, the chargers ramp up slowly until they hit either the predetermined charge rate, or the maximum voltage (which for A123 and LiFe is 3.6 volts per cell). They then reduce charging rate holding the voltage constant. Once the charging rate fall below a preset value (normally on the order of a couple milliamps), they are done. This process may happen quickly or slowly, depending on your charger and your battery condition. Further, these batteries are not shipped fully discharged. They have nominal charge to prevent reversing the cell polarity over time.
Its not a good idea to use a Pb setting for A123 cells, as these charge settings don't cut off at the maximum voltage, and you'll risk excess gassing from your cells at best, shortening cell life, or possibly causing a battery fire.
Brad
Its not a good idea to use a Pb setting for A123 cells, as these charge settings don't cut off at the maximum voltage, and you'll risk excess gassing from your cells at best, shortening cell life, or possibly causing a battery fire.
Brad
04-20-2010, 09:40 AM
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RE: Charging an A123 battery?
ORIGINAL: bkdavy
A123 (and other lithium chemistries) do not charge at a constant rate. Instead, the chargers ramp up slowly until they hit either the predetermined charge rate, or the maximum voltage (which for A123 and LiFe is 3.6 volts per cell). They then reduce charging rate holding the voltage constant. Once the charging rate fall below a preset value (normally on the order of a couple milliamps), they are done. This process may happen quickly or slowly, depending on your charger and your battery condition. Further, these batteries are not shipped fully discharged. They have nominal charge to prevent reversing the cell polarity over time.
Not necessarily true, depends on the electonics in the charger. If there is no current limiting, currents can be higher than what is safe and; if the voltage is not limited, they will NOT cut off when the battery approaches full charge.
Its not a good idea to use a Pb setting for A123 cells, as these charge settings don't cut off at the maximum voltage, and you'll risk excess gassing from your cells at best, shortening cell life, or possibly causing a battery fire.
Again, not entirely true, a properly designed Pb charger for 6 volts has a maximum voltage out of 6.7 +- 0.1 volts so will not overcharge a 2 cell A123 (in fact will not quite fully charge it). You can also charge a 4 cell A123 on a good 12 volt Pb charger as it will limit the voltage to approximately 13.7 volts so that is the maximum voltage it will charge the cells to.
Brad
A123 (and other lithium chemistries) do not charge at a constant rate. Instead, the chargers ramp up slowly until they hit either the predetermined charge rate, or the maximum voltage (which for A123 and LiFe is 3.6 volts per cell). They then reduce charging rate holding the voltage constant. Once the charging rate fall below a preset value (normally on the order of a couple milliamps), they are done. This process may happen quickly or slowly, depending on your charger and your battery condition. Further, these batteries are not shipped fully discharged. They have nominal charge to prevent reversing the cell polarity over time.
Not necessarily true, depends on the electonics in the charger. If there is no current limiting, currents can be higher than what is safe and; if the voltage is not limited, they will NOT cut off when the battery approaches full charge.
Its not a good idea to use a Pb setting for A123 cells, as these charge settings don't cut off at the maximum voltage, and you'll risk excess gassing from your cells at best, shortening cell life, or possibly causing a battery fire.
Again, not entirely true, a properly designed Pb charger for 6 volts has a maximum voltage out of 6.7 +- 0.1 volts so will not overcharge a 2 cell A123 (in fact will not quite fully charge it). You can also charge a 4 cell A123 on a good 12 volt Pb charger as it will limit the voltage to approximately 13.7 volts so that is the maximum voltage it will charge the cells to.
Brad
