Small lithium batteries

[Cerebus]

I have some small devices in which the batteries will not deplete to zero even if the device is not used for a year and if batteries were charged to 80% before device stored
But other devices, the batteries deplete quickly.

What is the logic behind it?
Is there a solution to looking after the batteries?

Go pro (or copies of) batteries seem to deplete if the device is stored for some some time.

A submersible camcorder taking 700mAh batteries also is found to have batteries (stored next to device) depleted after a while.

In contrast, 2 kindle fires (first gen) have 50% capacity after a year of storage?

What is the difference?

What can I do to keep the smaller batteries in good form? There will come a time when the batteries are no longer available.(5 are sitting next to the submersible camcorder now awaiting a full charge)

TIA

 

[William_H]

I have some small devices in which the batteries will not deplete to zero even if the device is not used for a year and if batteries were charged to 80% before device stored
But other devices, the batteries deplete quickly.

What is the logic behind it?
Is there a solution to looking after the batteries?

Go pro (or copies of) batteries seem to deplete if the device is stored for some some time.

A submersible camcorder taking 700mAh batteries also is found to have batteries (stored next to device) depleted after a while.

In contrast, 2 kindle fires (first gen) have 50% capacity after a year of storage?

What is the difference?

What can I do to keep the smaller batteries in good form? There will come a time when the batteries are no longer available.(5 are sitting next to the submersible camcorder now awaiting a full charge)

TIA

Batteries are being discharged either by the device itself or by natural loss of charge. (even if removed. ) Batteries will not discharge to zero from device current because as voltage falls discharge current becomes less usually in a very non linear manner. Not applicable but as an example an LED diode will take good current above about 3 volts but will take no current below that critical voltage. Many devices will have a small discharge current at all times when off.
I understood lithium.rechargeable batteries had quite small natural discharge over time. ol'will

 

[MontyMariner]

You know how some battery operated devices come with batteries fitted and a small plastic tab that you pull to activate the power.
Make yourself some plastic tabs and insert them when you're putting the device away for a length of time.

 

[Sea Change]

The natural self discharge rate of lithium batteries seems to be around 1-3% a month. If there's any parasitic draw then it will be worse. That will vary by device.

 

[Cerebus]

Thanks.

The small batteries that are flat (and not in a device) have obviously discharged because they are lithiums which have the discharge characteristics mentioned.

The kindle fires have bigger batteries and cannot be removed from the device (turned off) but have probably discharged but being larger batteries with larger capacity are not completely flat (50%).

The flat batteries I will charge to 100% (to recalibrate them) and try to maintain them at about 60% if not used. Not letting them get below 40% and not charging above 80%

Thanks

 

[st599]

All batteries self discharge to some extent. Chemical reactions within the battery reducing the number of electrons available, crystal formation ("memory") etc.

I seem to remember NiMH could discharge at 70% a month and exhibit memory effect.

 

[Cerebus]

What is the fully charged voltage of an old style lithium ion battery?

Label states 3.7V

In reality they charge to about … what is it ? 4.1v or 4.2v?

Of course, they should only be charged to 100% (4.2v?) now and again to recalibrate.

Normal useage charge to 80% capacity.

 

[Refueler]

What is the fully charged voltage of an old style lithium ion battery?

Label states 3.7V

In reality they charge to about … what is it ? 4.1v or 4.2v?

Of course, they should only be charged to 100% (4.2v?) now and again to recalibrate.

Normal useage charge to 80% capacity.

The max voltage of Li depends on the Chemistry .... LiIon can be had in lower (3.6v) or higher voltage (4.2v) capabilities .... but the standard is 4.2v

3.7v is the nominal level and the best storage level for the 4.2v format ....

For use - normal usage is to charge to 4.2v .... full 100%. There some people who believe that charging to 4.0 .. 4.1v gives better life - but the life of battery is dependent more on the rate of charge / discharge ... not on charging to max.

 

[Cerebus]

The max voltage of Li depends on the Chemistry .... LiIon can be had in lower (3.6v) or higher voltage (4.2v) capabilities .... but the standard is 4.2v

3.7v is the nominal level and the best storage level for the 4.2v format ....

For use - normal usage is to charge to 4.2v .... full 100%. There some people who believe that charging to 4.0 .. 4.1v gives better life - but the life of battery is dependent more on the rate of charge / discharge ... not on charging to max.

Interesting, I believed older lithium batteries liked to be discharged to 40% and charged to 80%.

Occasionally, to recalibrate, discharge fully to zero and charge to 100%.

My batteries are not new in the least. I seem to collect them, but never throw the old ones away in case they can be of SOME use even if in an emergency.

 

[Refueler]

Interesting, I believed older lithium batteries liked to be discharged to 40% and charged to 80%.

Occasionally, to recalibrate, discharge fully to zero and charge to 100%.

My batteries are not new in the least. I seem to collect them, but never throw the old ones away in case they can be of SOME use even if in an emergency.

Re-calibrate ???? Unless the battery has a BMS - there is no calibration of any battery ....

Li batterys deteriorate by way of Internal Resistance usually .,.. which makes the battery work harder to provide the power demanded ... this means observed shorter 'run-time' and often increased temp of the battery .... but once load removed .. the battery often bounces back giving impression its still reasonably charged - it is but its limited by that internal resistance and fails to deliver demanded output.

 

[lustyd]

My favourite batteries are DJI. They have a BMS on board and after about a month they burn down to 50% with an internal resistor (slow enough not to get hot). After that they never seem to go further down. I left some for 3-4 years and they were about 50% and seem to have no loss of performance or capacity.
It is infuriating though when you go to use the drone after a month and every battery is at 50%!

 

[Shaz77]

Slightly off subject here but I have a floating MOB torch hanging upside down in the cabin, next to the steps, (so it is not nicked,) with normal everyday batteries and I only change them every 5 years or more. I do keep them greased and of course the lamp is airtight.

 

[Refueler]

My favourite batteries are DJI. They have a BMS on board and after about a month they burn down to 50% with an internal resistor (slow enough not to get hot). After that they never seem to go further down. I left some for 3-4 years and they were about 50% and seem to have no loss of performance or capacity.
It is infuriating though when you go to use the drone after a month and every battery is at 50%!

I have a Phantom 3 Standard and a Phantom 3 Pro .... along with about 200 LiPo's .. some non DJI with BMS .. many without.

The DJI Phantom Batterys - 4S LiPoHV (that is 4.35v max per cell) have as you say a BMS. That BMS is user settable for how long battery sits fully charged before discharging via BMS to storage (3.85V per cell). I have mine set at 2 days - which is what most people I know with similar .. Mavics, P2, P3's etc ... set theirs to.

BUT - the DJI batterys WILL discharge past 50% and I have this as witnessed and also stated clearly by DJI forums .... the rate of discharge to storage is at a moderate rate - taking a few days .. but once reached - the rate falls to a very low value - this is because the battery BMS is still active in 'monitoring' the cells ... it does not shut off 100%.

You may have experienced 3 - 4yrs and still have working batterys - but I will be honest and suggest you were very lucky. Even DJI themselves in the forums advise to periodically charge up and let the BMS auto-storage function look after the batterys .....

 

[lustyd]

I didn’t know it was configurable, thanks will take a look. May not be on my Air and Mini 4 as they’re a bit lower in the range.
I didn’t leave them on purpose. Covid and a generally hostile attitude to drones in Britain meant it sat in a cupboard

 

[Refueler]

I didn’t know it was configurable, thanks will take a look. May not be on my Air and Mini 4 as they’re a bit lower in the range.
I didn’t leave them on purpose. Covid and a generally hostile attitude to drones in Britain meant it sat in a cupboard

The Air and Mini are not ones I have experience of .... I use the heavier Phantom - which is far more stable in wind etc. Even the original Mavic cannot match the Phantom stability.

Worth checking out about your battery setting .....

 

[Stemar]

If you use AA size lithium batteries, this is worth a watch

 

[lustyd]

AA size lithium batteries

An AA would be a 14500 not a 18650 since it’s 14mm diameter not 18mm and 50mm long not 65mm

 

[Refueler]

If you use AA size lithium batteries, this is worth a watch

18650 are not AA size.

As to brands - I use Sanyo and another reputable brand which I cannot recall at present ....

With regard to rechargeable NiMh .. I use Grundigs which are Ultra Low Self Discharge same as and half the price of Enerloops !

 

[Stemar]

An AA would be a 14500 not a 18650 since it’s 14mm diameter not 18mm and 50mm long not 65mm

Oops - sorry.

 

[lustyd]

I was just being nerdy, I assumed you knew