Li-Ion instead of Li-Po?
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Wojciech B
Nov 18, 2019, 9:23:07 AM11/18/19
to BeagleBoard
Hi,
Has anyone used Li-Ion instead of Li-Po batteries in BBBlue? MP2615 is used as charger and according to chip documentation it is "suitable for 1- or 2- cell lithium-ion or lithium-Polymer applications". Is anyone aware of any Li-Ion batteries contraindications ? The other question is about capacity. Can it be 3000mAh instead of suggested 1200mAh?
Regards
Robert Forsyth
Nov 18, 2019, 5:38:48 PM11/18/19
to BeagleBoard
Li-Po is a Li-Ion, just it has jelly/jello like chemical solution instead of liquid which makes them more leak resistant.
These cells often have a temperature dependant resistor to both ID the battery (capacity) and reduce overcharging danger.
Li-Po / Li-Ion cells should not be charged when the temperature is below 0 Celsius or for longer than 5 hours.
Wojciech B
Dec 1, 2019, 12:49:40 PM12/1/19
to BeagleBoard
Thank you for the answer. I also found that my LI-Ion have additional internal protection and they simply do not allow overcharging so I hope I am on the safe site.
What is the reason for 5 hours limit? Assuming I have 3000mAH battery and 500mA charger it would always take longer to charge battery.
Regards,
W
Robert Forsyth
Dec 1, 2019, 7:28:38 PM12/1/19
to BeagleBoard
It seems a Li-ion cell should be charged in 3 hours. When twice the capacity has been applied, stop charging. Li-ion cells should not be trickle charged. I don't know why 5 hours limit.
Dennis Lee Bieber
Dec 2, 2019, 1:51:54 PM12/2/19
to Beagleboard
On Sun, 1 Dec 2019 09:49:40 -0800 (PST), in
gmane.comp.hardware.beagleboard.user Wojciech B
"""
The advised charge rate of an Energy Cell is between 0.5C and 1C; the
complete charge time is about 2–3 hours. Manufacturers of these cells
recommend charging at 0.8C ...
"""
"""
Li-ion cannot absorb overcharge. When fully charged, the charge current
must be cut off. A continuous trickle charge would cause plating of
metallic lithium and compromise safety
"""
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
https://www.powerstream.com/li.htm
"""
The lithium ion battery is easy to charge. Charging safely is a more
difficult. The basic algorithm is to charge at constant current (0.2 C to
0.7 C depending on manufacturer) until the battery reaches 4.2 Vpc (volts
per cell), and hold the voltage at 4.2 volts until the charge current has
dropped to 10% of the initial charge rate. The termination condition is the
drop in charge current to 10%. The top charging voltage and the termination
current varies slightly with the manufacturer.
However, a charge timer should be included for safety.
The charge cannot be terminated on a voltage. The capacity reached at 4.2
Volts per cell is only 40 to 70% of full capacity unless charged very
slowly. For this reason you need to continue to charge until the current
drops, and to terminate on the low current.
"""
"""
When the charge rate during the constant current phase is low, the charger
process will spend less time during the constant voltage tail. If you
charge below about 0.18 C, the cell is virtually full when the 4.2 volts is
reached. This can be used as an alternative charge algorithm. Just charge
below 0.18C constant current and terminate the charge when the voltage
reaches 4.2 volts per cell.
"""
On a 3000mAH battery, 0.18C is 540mA, so a 500mA charger would be
following this simplified algorithm -- you just need to monitor voltage and
kill the charger as appropriate.
--
Dennis L Bieber
gmane.comp.hardware.beagleboard.user Wojciech B
<wojciech.ben-Re5J...@public.gmane.org> wrote:
>Thank you for the answer. I also found that my LI-Ion have additional
>internal protection and they simply do not allow overcharging so I hope I
>am on the safe site.
>What is the reason for 5 hours limit? Assuming I have 3000mAH battery and
>500mA charger it would always take longer to charge battery.
>Regards,
>W
>
https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
>Thank you for the answer. I also found that my LI-Ion have additional
>internal protection and they simply do not allow overcharging so I hope I
>am on the safe site.
>What is the reason for 5 hours limit? Assuming I have 3000mAH battery and
>500mA charger it would always take longer to charge battery.
>Regards,
>W
>
"""
The advised charge rate of an Energy Cell is between 0.5C and 1C; the
complete charge time is about 2–3 hours. Manufacturers of these cells
recommend charging at 0.8C ...
"""
"""
Li-ion cannot absorb overcharge. When fully charged, the charge current
must be cut off. A continuous trickle charge would cause plating of
metallic lithium and compromise safety
"""
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
https://www.powerstream.com/li.htm
"""
The lithium ion battery is easy to charge. Charging safely is a more
difficult. The basic algorithm is to charge at constant current (0.2 C to
0.7 C depending on manufacturer) until the battery reaches 4.2 Vpc (volts
per cell), and hold the voltage at 4.2 volts until the charge current has
dropped to 10% of the initial charge rate. The termination condition is the
drop in charge current to 10%. The top charging voltage and the termination
current varies slightly with the manufacturer.
However, a charge timer should be included for safety.
The charge cannot be terminated on a voltage. The capacity reached at 4.2
Volts per cell is only 40 to 70% of full capacity unless charged very
slowly. For this reason you need to continue to charge until the current
drops, and to terminate on the low current.
"""
"""
When the charge rate during the constant current phase is low, the charger
process will spend less time during the constant voltage tail. If you
charge below about 0.18 C, the cell is virtually full when the 4.2 volts is
reached. This can be used as an alternative charge algorithm. Just charge
below 0.18C constant current and terminate the charge when the voltage
reaches 4.2 volts per cell.
"""
On a 3000mAH battery, 0.18C is 540mA, so a 500mA charger would be
following this simplified algorithm -- you just need to monitor voltage and
kill the charger as appropriate.
--
Dennis L Bieber
Wojciech B
Dec 2, 2019, 7:05:56 PM12/2/19
to beagl...@googlegroups.com
Thank you for the answer and links! Really great reading extending knowledge.
--
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