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Battery charge level for long time storage.

Kevin
(@kevin)
Estimable Member Customer

Would it be possible to add a feature to prepare/charge a battery to the recommended levels for long time storage?

This is useful if the battery will be in stock for a long time before selling.

And by the way, what is the recommended charge level in this case?

 

Thanks

 

 

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Topic starter Posted : 25/07/2021 6:33 am
torture
(@torture)
Member Moderator

Charge the battery to 40% and you can store it. The storage voltage of the cells should be 3.5-3.6v.

 

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Posted : 25/07/2021 8:07 am
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batFix
(@batfix)
Reputable Member
Posted by: @kevin

And by the way, what is the recommended charge level in this case?

some good reading from MIT paper is here

Lithium Ion Battery (mit.edu)

Lets Make NLBA Great ! Together.

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Posted : 25/07/2021 8:44 am
Kevin liked
DjiBattWorkshop
(@djibattworkshop)
Member Moderator
Posted by: @kevin

And by the way, what is the recommended charge level in this case?

Just an example.

All DJI batteries with LiPo and LiHv cells have autodischarge to storage feature, so called DTS. BMS stops discharging the cells as soon as 60% of RSoC is reached which corresponds to 3.9v for LiHv 3.80 (4.35V) chemistry.

For LiPo 3.7 (4.2V) same percentage level corresponds to less voltage of about 3.8v.

Some sources state that optimal storage level is much less at about 30% of RSoC.

But if battery with 30% of charge will be left for long storage period there is a chance it will be depleted below Permanent Failure threshold thus being locked.

So actually storage level is compromise parameter which depends on how long you plan to store the cells, in order to give them enough capacity reserve for selfdischarge and bms consumption.

Before putting to storage, it's highly recommended to transfer the battery monitoring circuit to hibernation or shipment state to reduce power consumption. In that state battery could be stored much longer time than in active state due to extremely low power consumption.

As a conclusion it would be nice to have such an option or dedicated Storage button in the Nlba device.

By pressing it battery is charged or discharged to selectable storage level, after it reached, firmware specific SHIP command is sent to the chip to transfer to hibernation.

 

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Posted : 25/07/2021 9:33 am
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batFix
(@batfix)
Reputable Member
Posted by: @djibattworkshop

after it reached, firmware specific SHIP command is sent to the chip to transfer to hibernation.

Will it require other special cmd to begin work normally ? "unSHIP" ?

Lets Make NLBA Great ! Together.

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Posted : 25/07/2021 9:49 am
DjiBattWorkshop
(@djibattworkshop)
Member Moderator

no, return to normal mode is done by standard Wake-up procedure, i.e. by applying external voltage, inserting a battery in laptop etc.

 

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Posted : 25/07/2021 9:55 am
Kevin liked
Kevin
(@kevin)
Estimable Member Customer

Thanks All, this is very helpful.

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Topic starter Posted : 25/07/2021 11:28 am
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