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Old 05-25-2009, 01:52 PM   #1
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Default LiPo Race Charging?

I am just getting back into the hobby with LiPo instead of NiMh. Does it matter at what rate you charge a LiPo for better discharge? If it is a 5000 pack, and you charge it @ 2.5A vs 5A, will it still discharge the same? (My ancient charger is limited to 2.5A for LiPo )

I think I remember you always wanted to charge NiMh batts higher amps for racing. Less charge current was longer run time...

I am not sure if it matters in LiPo...
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Old 05-25-2009, 02:11 PM   #2
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I am just getting back into the hobby with LiPo instead of NiMh. Does it matter at what rate you charge a LiPo for better discharge? If it is a 5000 pack, and you charge it @ 2.5A vs 5A, will it still discharge the same? (My ancient charger is limited to 2.5A for LiPo )

I think I remember you always wanted to charge NiMh batts higher amps for racing. Less charge current was longer run time...

I am not sure if it matters in LiPo...
Charging rate for lipo only determines how fast the battery will charge - no effect on performance if you charge at 5A instead of 2.5A.
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Old 05-25-2009, 02:24 PM   #3
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Lipo Chargers charge using a CC/CV procedure.

CC = Constant Current.

The Current or Amperage stays at the pre-set value until the LIPO Charge Voltage is reached. (Generally 4.20 volts per cell =/- .02 volts per cell)

A 5000 mAh pack should be a 2 cell, so it would charge to 8.38 - 8.44 volts.

Once the charger sees the voltage, it starts turning down the amperage, until the batter is fully charged.

a 2.5 amp charge on a 5000 mAh battery would be considered a .5 c charge, which is very slow....and if you have to put 2000 - 2500 mAh back into your pack after a race, it's going to take a LONG TIME. Probably well over an hour....if you are running a motor combo and time frame that uses MORE than that in a race..you better show up with 3 batterys CHARGED on Race Day!!
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Old 05-25-2009, 03:48 PM   #4
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Lipo Chargers charge using a CC/CV procedure.

CC = Constant Current.

The Current or Amperage stays at the pre-set value until the LIPO Charge Voltage is reached. (Generally 4.20 volts per cell =/- .02 volts per cell)

A 5000 mAh pack should be a 2 cell, so it would charge to 8.38 - 8.44 volts.

Once the charger sees the voltage, it starts turning down the amperage, until the batter is fully charged.

a 2.5 amp charge on a 5000 mAh battery would be considered a .5 c charge, which is very slow....and if you have to put 2000 - 2500 mAh back into your pack after a race, it's going to take a LONG TIME. Probably well over an hour....if you are running a motor combo and time frame that uses MORE than that in a race..you better show up with 3 batterys CHARGED on Race Day!!
A new charger would probably be cheaper than 3 batteries.
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Old 05-25-2009, 06:56 PM   #5
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Thanks to all who replied! You guys are very helpfull.
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Old 05-25-2009, 07:13 PM   #6
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one thing about lipo's, you can charge them anytime, at mah its stated for. All lipo's chargers will shut off when amperage is acquired. It just may take 1500mah to 2000mah to peak out a 5000mah lipo. You never see it charge upto 5000mah. You never discharge lipo to 0v, lipo cutout voltage is 3v for longevity.
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Old 05-25-2009, 09:02 PM   #7
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one thing about lipo's, you can charge them anytime, at mah its stated for. All lipo's chargers will shut off when amperage is acquired. It just may take 1500mah to 2000mah to peak out a 5000mah lipo. You never see it charge upto 5000mah. You never discharge lipo to 0v, lipo cutout voltage is 3v for longevity.
Just for clarifications, the cutoff is 3v per cell, so if you have a two cell battery, you dont want to let the voltage drop below 6v, a 3 cell below 9v and so on..
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