Battery discharge ? Help

[Hayabusa]

I have my batts set to discharge after 3 days. I charged them I guess about 3 days ago. Anyways, I’m trying to head out to get some pics/vid of the Symphony of the Seas. (Largest cruise ship)
All my batts have 4 bars when pressed but when I hook every up it says self discharge-storage.
And won’t charge on charger because, I guess all lights are still full so thinks it’s charged. Idk.
I’m afraid to fly with it saying that.
what’s best thing to do?
I turned them on to see if I can get to 3 bars and then charge.

help

 

[old man mavic]

what you could try is to turn on the battery and then plug it in to the charger and see if it starts to charge

 

[Hayabusa]

what you could try is to turn on the battery and then plug it in to the charger and see if it starts to charge

That worked.
They are charging but once again, I missed my window fir that ship. Leaves at 4pm,
I’ll try again next week.?

thanks

 

[Hayabusa]

Let’s say I was already out and did not have a charger. Could you still fly as normal with them in self discharge mode?
Just curious

 

[old man mavic]

That worked.
They are charging but once again, I missed my window fir that ship. Leaves at 4pm,
I’ll try again next week.?

thanks

glad it helped good luck with your project

 

[old man mavic]

Let’s say I was already out and did not have a charger. Could you still fly as normal with them in self discharge mode?
Just curious

cant honestly answer that question as i have never had it happen to me ,what you could do is just do a hover test and watch what happens i guess ,another thing to do is if you have charged them up and the 3,day auto discharge is eminent just press the button on the battery and it will reset the timer

 

[SXB1]

Let’s say I was already out and did not have a charger. Could you still fly as normal with them in self discharge mode?
Just curious

I have mine set to discharge after 3 days, had been 2 weeks before I checked them and yes they had discharged to 50%. Then 1 evening I wanted to check some settings out so started up my mav, which showed the self discharge mode on screen, I did however carry on. Hovered for a minute after altering settings and then a very brief flight just from the back garden to check settings and then down.
Everything was as normal, however if I was intending to do a proper flight so to speak I would have charged the batteries back up fully ??

 

[WithTheBirds]

Let’s say I was already out and did not have a charger. Could you still fly as normal with them in self discharge mode?
Just curious

It is a universal recommendation to commence flight with a fully charged battery. This isn’t simply to ensure the capacity is reported correctly, there is a larger and likely of greater significance problem to be avoided. That is the chance that the cells have gone out of balance during an auto discharge event. Charging the pack brings the cells back into balance, commencing flight with the cells out of balance will quickly lead to the the lower voltage cell(s) sagging under load- the pack will shut down when any cell reaches LCV. A battery is only as good as the weakest cell.

 

[DanMan32]

It also makes sure the gas gauge is accurate.

 

[WithTheBirds]

It also makes sure the gas gauge is accurate.

Yes, as I stated. It is a secondary consideration however. The real problem seems to be the out of balance cell voltage condition which seems to relate directly to the bleed resistors switched in to perform the auto discharge terminate the cells individually (the same resistors that are swtched in during balance charging to bleed off excess voltage as required). You don’t need the resistors have very high difference in value to end up with unevenly discharged cells (this would be avoided by bulk discharge with a series connection).

Reported SOC=Q/Qmax, where Q is passed charge (derives by coulomb counting algorithm) from the full-charge state and QMax is max chemical capacity. That is assuming the Texas Instruments Gas Gauging with impedance track algorithm (or equivalent system) is employed. Cell imbalance won’t cause the total SOC to be reported incorrectly, it is the cells ability to deliver the stored charge in a series connection which is the problem. The lower voltage cell(s) in the pack will discharge at a faster rate, significantly faster with greater voltage difference and at an increasing rate during discharge. It can’t end well.

 

[DanMan32]

The TX BMS uses more complex algorithm than simple coulomb counting. Voltage, current, temperature and recent history is likely also taken into account.

 

[WithTheBirds]

The TX BMS uses more complex algorithm than simple coulomb counting. Voltage, current, temperature and recent history is likely also taken into account.

Thank you for making my point, the determination of SOC and capacity/run time to empty is, as you have suggested an advanced algorithm using many measured and derived parameters.

You might have been a little hasty in your assuming I had suggested it might be simple column counting. Q is, and can be with little significant error, derived by coulomb counting- it is Qmax that is of greatest importance to accuracy and updated in real time, including the parameters you mentioned and, even more critical to accuracy and absent from those you cited, the derived internal resistance value.

 

[DanMan32]

The thing is, short cycles could confuse the algorithm, where a full cycle can help normalize it.

I agree, the main reason to "deep cycle" is cell balance, but normalizing the gas gauge is another reason.

 

[WithTheBirds]

The thing is, short cycles could confuse the algorithm, where a full cycle can help normalize it.

I agree, the main reason to "deep cycle" is cell balance, but normalizing the gas gauge is another reason.

How did we get to deep cycling? Cell balance is achieved by the SOC switching in resistors to bleed off individual cells at higher voltage during the constant voltage charge phase. Not by discharging. Deep discharge does little to assist in gas gauging calibration. If you are interested in understanding why that is I would recommend reading the TI white papers on impedance track and gas gauging. They claim within 1% accuracy over the life of the pack without the need for deep discharge. It is simple coulomb counting that require a regular deep discharge for accuracy in reported SOC and usable remaining capacity. The Ongoing tracking of IR and cell health provides that deteriorating cell condition can be accounted for with high accuracy.

 

[offtheback]

How did we get to deep cycling? Cell balance is achieved by the SOC switching in resistors to bleed off individual cells at higher voltage during the constant voltage charge phase. Not by discharging. Deep discharge does little to assist in gas gauging calibration. If you are interested in understanding why that is I would recommend reading the TI white papers on impedance track and gas gauging. They claim within 1% accuracy over the life of the pack without the need for deep discharge. It is simple coulomb counting that require a regular deep discharge for accuracy in reported SOC and usable remaining capacity. The Ongoing tracking of IR and cell health provides that deteriorating cell condition can be accounted for with high accuracy.

Yikes!Things were much simpler in the days of carbon zinc batteries?

 

[crlmjohnson]

Let’s say I was already out and did not have a charger. Could you still fly as normal with them in self discharge mode?
Just curious

yes. I have. press the button on the batteries twice. before installing them. it stops the discharge.
but I do not think this is recommend. but it works.

 

[D-Rosin]

I have mine set to discharge after 3 days, had been 2 weeks before I checked them and yes they had discharged to 50%. Then 1 evening I wanted to check some settings out so started up my mav, which showed the self discharge mode on screen, I did however carry on. Hovered for a minute after altering settings and then a very brief flight just from the back garden to check settings and then down.
Everything was as normal, however if I was intending to do a proper flight so to speak I would have charged the batteries back up fully ??

whats the discharge sign means?
and pushing the button on the battery will stop this?
is there a way to set the discharge time?

 

[crlmjohnson]

whats the discharge sign means?
and pushing the button on the battery will stop this?
is there a way to set the discharge time?

pushing the battery will reset the discharge time..(start over)...stopping it....

The battery will be discharge up to that time(if this makes sense)..

you have to go into your settings, and you can change the days, that the batteries start to discharge.

I think by default...after the last update...the batteries start to discharge after 5 days of idle time..to storage charge.

 

[D-Rosin]

pushing the battery will reset the discharge time..(start over)...stopping it....

The battery will be discharge up to that time(if this makes sense)..

you have to go into your settings, and you can change the days, that the batteries start to discharge.

I think by default...after the last update...the batteries start to discharge after 5 days of idle time..to storage charge.

so whats the best recommendation if you dont fly much to change this setting?
there is allot going on in this controller lol where do i find these setting to change this?

 

[crlmjohnson]

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i looked, but I think it has changed. last since the last update.

from another forum link: Setting number of days to discharge batteries

this used to be there: