I meant DO NOT put them in the freezer at all - put them in the refrigerator for 15 mins!
Battery not charging
- Thread starter danilocd
- Start date
The different types of Lithium batteries are described here Types of Lithium-ion Batteries – Battery University
Early DJI battery cells tended to go out of balance (which reduced capacity, similar to a memory effect) and the easiest way to rebalance was to run the battery down and fully recharge. It shortened the total life of the battery but at least maximum possible flight times were obtained for each use. Now with improved software and hardware the "fuel gauge" on the battery is more accurate and only needs rebalancing rarely. I don't know why DJI didn't explain this to us.
That physical memory effect is very slight and only applies to LiFePO4 batteries as commonly used in EVs. It is exacerbated by the regenerative braking in EVs that give the battery multiple small cycles during every use. The digital memory effect is also a problem in EV's because of the flat Voltage/Discharge curve in LiFePO4 batteries means the "fuel gauge" can easily be confused about the actual state of charge of the battery but it is important to realize that the digital memory effect is only an error in measurement, not a real reduction in battery capacity.
Thanks for the info, that was really informative.
However.... all I want DJI to do is to make a statement informing us, their customers, why we no longer need to "cycle" our very, very expensive batteries, that's all.
Just got back from a drone less holiday. Left the 3 batteries cycling in the P4CH Charging Hub on Storage mode for 4 weeks.
The one Phantom 4 battery is still working fine. The 2 Phantom 4 Pro batteries are totally unresponsive. Tried to charge them individually (without the hub) overnight with no success. Tried to put them in the drone with no success. Nor sure what to do now. Any suggestions?
At 180USD a pop and having completed 50 flights with one and 20 flights with the other, that would make a charge cost of more than 5USD per flight (without counting the cost of electricity)...
The one Phantom 4 battery is still working fine. The 2 Phantom 4 Pro batteries are totally unresponsive. Tried to charge them individually (without the hub) overnight with no success. Tried to put them in the drone with no success. Nor sure what to do now. Any suggestions?
At 180USD a pop and having completed 50 flights with one and 20 flights with the other, that would make a charge cost of more than 5USD per flight (without counting the cost of electricity)...
The 'maintenance' cycling of LiPo's is a myth and wasted time and risks damaging cells of a LiPo unless controlled properly - which DJI setup prevents.
Use of a programmable LiPo charger can 'kickstart' a LiPo but is best left to those who have knowledge of what is needed ? Basically using either NiCd or NiMh mode - it is only banging in voltage similar to a DJI charger anyway.
The better way with a LiPo charger is to use the LiPo mode with setting : LiPo Charge, 4S, 5A ....
If the LiPo charger has LiPo High Voltage mode (LiHV) - then use that ... LiHV Charge, 4S, 5A
(LiPo standard charges to 4.2V ... LiHV charges to 4.35V per cell ... )
Before connecting - battery needs to be switched on ... then plug into LiPo charger.
I use LiHV chargers a lot on my DJI batterys ....
Nigel
Please provide evidence of Memory Effect with LiPo's ... because LiPo have no memory effect at all.... if they did - then continual use of storage charge would create unuseable batterys ...
Memory effect is only with NiCd and is related to repeated partial discharge ... even NiMh do not have memory effect to same as NiCd.
Nigel
It has been shown that 'conditioning' when new can give you a few mAh ... but once a LiPo has been cycled a few times - there is no benefit to deep cycling and no memory effects.
The only item that affects LiPo's during their operating life is : Internal Resistance.
This increases over the life of LiPo use until its high enough to create such voltage drop that the battery no longer performs well. As the Ri increases - the temperature of battery in use will rise ever higher as well .. a good sign of this happening.
As regards many online sources of info ... many of them are not updated and still put out old info. Battery world like computers evolves daily ... and what was excellent info last month is old hat now.
The only item that dos not change with LiPo's .......... treat with respect, do not overdischarge, do not charge at too high a rate, store at storage level, store in cool place well away from sources of heat or flammable materials, do not leave charging LiPo's unattended.
Nigel
Intelligent ? The board fitted to the DJI batterys ..... mmmmmm ...
Lets look at a DJI battery. I have had a number apart and myself and others as a group have tried various actions ...
a) The cells used are LiPo High Voltage versions that top out at 4.35V per cell. The top 10% of charge acts as HV and then the LiPo follows same pattern as a standard 4.2V per cell LiPo ... this is why standard LiPo cell storage advise works 100% for the HV version as well.
b) The cells do have balance and power leads, but both go to the small circuit board fitted at front of pack inside case.
c) The board reduces the connections to outside to two sets ... main +/- and the secondary smaller +/- contacts.
d) The boards main function is as Charge controller. It replaces what a LiPo charger has and means DJI charger is a plain regulated power brick of 17.5V only. The board monitors charge rate and terminates at the 17.4V total voltage state.
e) Secondary action of the board in terms of battery is to have the setting of when auto discharge is initiated. DJI default is 10 days. This is ok if the P3 is used often .. but is not advised as 10 days is too long. Any damage by having full charge then is accumulative. Better to reduce this to 2 or 3 days maximum. The discharge is ';resistive discharge' - this means energy is dissipated as heat and therefore is slow. Discharge continues at steady rate till below 65%, then slows and continues... well past 50%. Eventually battery reaches a low level of storage and enters Hibernation mode. This then basically cuts off discharge and only physical chemistry takes over.
f) The board has a third function of providing battery data for telemetry based on the balance lead connection. This relays to your display the voltage of each cell ... no load when on ground, loaded when flying. The general display is an average of the 4 cells figures.
OK onto the 'myths' of this 'intelligent' board.
1. It is a total voltage monitor at heart and does not actually correctly balance or even out cells.
2. When charging - once it detects 17.4V regardless of cells inbalance - it terminates charge, unlike a LiPo charger that in final stages balances cells.
3. Deep discharge is not fully monitored or controlled and therefore risks damage to one or more cells. The board terminates at a total voltage figure.
It would be very good if DJI would actually give the information we would all like to have - but they do not and myths get repeated and become accepted fact. Its then very difficult to convince some of the errors.
I will not claim to be 100% correct - but all above has been observed and tested to be as accurate as we can determine.
One of my biggest concerns : is the DJI charger in fact. It is same as your Laptop computer supply .. a regulated power brick. Nothing special, nothing fancy. It will deliver 17.5V till you remove power from it. It has no safety cut-out that we could find. This then means that it relies on the Battery and its Board to cut out when full charged. What happens if there's a fault in the battery or board ?
I prefer using a LiPo charger because I have a second safety back-up .... the LiPo charger will cut out immediately it detects a fault ....
Nigel
Thank you ... someone who doesn't follow the myths that have built up about these batterys.
Cheers
Nigel
100% spot on !!
Trouble is it removes the possibility of knowledgeable users to maximise efficient charging and use of the batterys.
99% of the RC model world works with plain LiPo batterys ... without problem. I have seen DJI batterys - one being my own after its 'swim in the river' become dangerous. Given my limited experience .. I have seen as many DJI batterys fail as normal batterys, leaving out wear and tear.
Nigel
You did what ???? You left LiPO batterys cycling for 4 weeks ????
Have you never seen a LiPo fail into flames ?
Back to cycling - a) its a total waste of time ... and b) if you left packs cycling for 4 weeks - I am not surprised they are useless. Can you imagine the heat and turmoil inside those packs ? The 'boards' being bombarded for 4 weeks trying to regulate charge rate in / out continually ??
I've read and heard some incredible things to do with LiPo charging / use - but that just about beats all hands down !!
Nigel
I agree about the evolution of everything, Nigel, but given the batteries we use in our ACs today are not going to evolve any further, that was my interest.
I've since spoken to a UK Lipo manufacturer and they too recommend cycling their batteries and in their view, cycling any Lipo - including DJI - may derive a benefit but world certainly not be detrimental to its performance.
I prefer independent expert advice.
Cyc,ring has been shown to only benefit a new battery and has virtually no effect on a used battery other than using up life. If I was a manufacturer - I would love everyone to cycle as often as possible.
Itbakso depends on what level of cycling you do - the old DJI recc'd deep cycling is a definite no-no and even DJI recognize that now. But cycling from storage to full and back etc. - would not be detrimental but again really only uses up life cycles.
My basis of battery info is from a firmer senior tech from Mallory, who are famous for Duracell etc. I know I said I prefer independent - that's when I cannot get info from him .... a long standing friend.
Nigel
Cyc,ring has been shown to only benefit a new battery and has virtually no effect on a used battery other than using up life. If I was a manufacturer - I would love everyone to cycle as often as possible.
Itbakso depends on what level of cycling you do - the old DJI recc'd deep cycling is a definite no-no and even DJI recognize that now. But cycling from storage to full and back etc. - would not be detrimental but again really only uses up life cycles.
My basis of battery info is from a firmer senior tech from Mallory, who are famous for Duracell etc. I know I said I prefer independent - that's when I cannot get info from him .... a long standing friend.
Nigel
Sorry not being difficult - but LiPo are well documented to lose performance due to internal resistance .... not the same as NiCd memory effect. Its funny actually that even NiCd memory effect is argued about !
Nixx are recognized as benefiting from cycling - this breaks up 'chrystaline' formations.
Nigel
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