Battery Storage - Principles / Offseason

01 Nov 2015 10:49 AM | Marshall Henley (Administrator)

AUTHOR: Jonathan Hendrickson

Winter is on its way and you may not know it but your electric planes need some winterizing just like your gas or glow planes.  You need to pay particular attention to your batteries.  There are several different types of batteries and different storage methods/procedures for each.

LiPo or Li-ion

LiPo batteries should be stored at about 50% capacity. This is approximately 3.75-3.85 volts per cell.  They should be stored in a cool dry location in a LiPo safe bag or fireproof container.  To get the best possible capacity retention your LiPo should be stored at 32° F.  Storage at this temperature has a capacity loss of 2% per year.  Storage at 72° will result in a capacity reduction of 4% per year.  A good way to achieve the 32°F storage would be to refrigerate them, but make sure that the batteries are placed in a plastic bag to protect against condensation before putting them in your LiPo safe bag.

LiPo’s should always be stored in the method above even during the flying season.  It is good practice to charge the battery to full the same day or the day before you are going to use it and then return it to 50% capacity for storage.  LiPo’s left fully charged will have their useful life drastically reduced.

LiFePO4
(A123 or Lithium Iron Phosphate)

LiFePO4 batteries store similar to LiPo’s, but do NOT need the special LiPo storage bag for fire prevention.  However the storage voltage is less at 3.2-3.35v per cell. They should also be stored at lower temperatures like the LiPo’s.

Storage Voltages

LiPo

6s pack = 22.86v

5s pack = 19.05v

4s pack = 15.24v

3s pack = 11.43v

2s pack = 7.62v

1s pack = 3.81v

LiFePO4

6s pack = 20.1v

5s pack = 16.75v

4s pack = 13.4v

3s pack = 11.2v

2s pack = 6.7v

1s pack = 3.35v

NiMH (Nickel Metal Hydride)

Ni-MH batteries should be kept clean and dry during storage. They can be stored for many months in a charged or discharged state without any detrimental effects as long as they are not exposed to extreme temperatures for any long period of time. After storage the battery should be charged and/or cycled before use.


Winter is on its way and you may not know it but your electric planes need some winterizing just like your gas or glow planes.  You need to pay particular attention to your batteries.  There are several different types of batteries and different storage methods/procedures for each.

LiPo or Li-ion

LiPo batteries should be stored at about 50% capacity. This is approximately 3.75-3.85 volts per cell.  They should be stored in a cool dry location in a LiPo safe bag or fireproof container.  To get the best possible capacity retention your LiPo should be stored at 32° F.  Storage at this temperature has a capacity loss of 2% per year.  Storage at 72° will result in a capacity reduction of 4% per year.  A good way to achieve the 32°F storage would be to refrigerate them, but make sure that the batteries are placed in a plastic bag to protect against condensation before putting them in your LiPo safe bag.

LiPo’s should always be stored in the method above even during the flying season.  It is good practice to charge the battery to full the same day or the day before you are going to use it and then return it to 50% capacity for storage.  LiPo’s left fully charged will have their useful life drastically reduced.

LiFePO4
(A123 or Lithium Iron Phosphate)

LiFePO4 batteries store similar to LiPo’s, but do NOT need the special LiPo storage bag for fire prevention.  However the storage voltage is less at 3.2-3.35v per cell. They should also be stored at lower temperatures like the LiPo’s.

Storage Voltages

LiPo

6s pack = 22.86v

5s pack = 19.05v

4s pack = 15.24v

3s pack = 11.43v

2s pack = 7.62v

1s pack = 3.81v

LiFePO4

6s pack = 20.1v

5s pack = 16.75v

4s pack = 13.4v

3s pack = 11.2v

2s pack = 6.7v

1s pack = 3.35v

NiMH (Nickel Metal Hydride)

Ni-MH batteries should be kept clean and dry during storage. They can be stored for many months in a charged or discharged state without any detrimental effects as long as they are not exposed to extreme temperatures for any long period of time. After storage the battery should be charged and/or cycled before use.


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