How bad is it really to store battery at 100%?
- Thread starter Saudio
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agreed.... The figures I quoted earlier (from the battery university) suggest keeping your packs flight ready at 100% SOC you are throwing away 1/4 of your usable capacity in a year (above what you would resting at 40%).
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Well I only used one of them so the 2nd battery remained 100% full and was stored like that. About a week went by and I used that same battery to update my firmware and got the message I had a bad cell. Long story short that battery is now useless and DJI only warranties the batteries for 6mos so I'll have to buy another 6mo warrantied DJI Battery.
That battery above only had 8 charge cycles on it.I won't be leaving mine stored fully charged. Also I believe we can change the # of days before it will auto discharge in the DJI Go App. Mine was set to default.
Storing your battery fully charged for one week will not damage a cell and render the battery useless. What happened to you was merely a coincidence. Just because you're advised not to leave a battery fully charged for long, it doesn't mean that any bad thing that happens while you do that is *caused* by the battery being at 100%. Storing your battery at 100% causes a gradual decrease in the battery capacity, which happens over months, by a few percentage points every month. It doesn't nuke the battery in 7 days.
THIS IS NOT DJI SPECIFIC! But I have a neighbor (I live in an aviation development), who will NEVER leave liPo batteries fully charged again. THIS IS NOT CERTAIN, but his hangar caught fire, and burned a million dollars worth of airplanes, an antique motorcycle collection, and a lifetimes' worth of tools, most likely because he had recharged a full set of tool liPo batteries, and left them on the workbench where the fire was traced to starting---------
Rereading the above extensive comment about the results of leaving a battery fully charged----I think that It is a pretty safe supposition that the batteries that caused the hangar fire DID short between the anode/cathode, "which will cause a fire"-----they were new batteries, "exchanged because the previous ones were defective", and the three of them had just been fully charged before being left on the bench-----I emphasize AGAIN, these WERE NOT DJI "smart batteries", just that they were LiPo batteries.
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In addition to the above advice. I believe that the greatest cause of LiPo batteries catching fire is excessive heat causing insulation to breakdown or due to LiPo damage due to sudden impact caused by a crash or a fall. If a battery swells due to excessive heat or due to an accident it is best to discard that LiPo. However storing undamaged fully charged batteries at room temperature is not likely to cause a fire.
I can tell you that if you take a fully charged battery and leave it fully charged at room temp, it will swell. I know this because I have a counterfeit lipo that works great in my P2V but, unbeknownst to me earlier, doesn't have auto-discharge.
Edit: It was at about three weeks that I noticed the swelling and then realized it wasn't auto-discharging.
Edit: It was at about three weeks that I noticed the swelling and then realized it wasn't auto-discharging.
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Thank you for your information. If I store a fully charged battery for more than a few hours I keep it in the refrigerator, and so far no problems.
Excellent YouTube vid about "critical Low Voltage" problem due to cold batteries.
This happened to me last week flying in cold weather in Chicago. Put a full charge battery in and took the P3 up - luckily only 30' away- and got a "crital low voltage" warning. Brought it right down and let the battery warm up with props spinning. Was fine after battery got to about 25° C temp. The warning happened because battery was at 18°.
From that point on I put my next battery to fly inside my coat to keep battery warm. No problems after that.
Reason I mention is for the post about keeping batteries in the fridge - good idea & I think this summer I may do that. But more important- keep a cooler in the car with a reusable ice pack just so if I do have to lock up the car they won't over heat.
Then make sure each battery I want to use gets warmed up a bit before sending the bird 400' up...
I'm in Portland this week and first dawn here temps in upper 40's (Farenheight) did some flying and one of the batteries sitting in an open case gave me a Damaged cell warning right away. So I brought it down and didn't use that one. But later in the day when it was warmer, put it back in & looked at all the stats, cell voltage & what not, it was fine. And have flown it since. Again, it was a cold battery.
This happened to me last week flying in cold weather in Chicago. Put a full charge battery in and took the P3 up - luckily only 30' away- and got a "crital low voltage" warning. Brought it right down and let the battery warm up with props spinning. Was fine after battery got to about 25° C temp. The warning happened because battery was at 18°.
From that point on I put my next battery to fly inside my coat to keep battery warm. No problems after that.
Reason I mention is for the post about keeping batteries in the fridge - good idea & I think this summer I may do that. But more important- keep a cooler in the car with a reusable ice pack just so if I do have to lock up the car they won't over heat.
Then make sure each battery I want to use gets warmed up a bit before sending the bird 400' up...
I'm in Portland this week and first dawn here temps in upper 40's (Farenheight) did some flying and one of the batteries sitting in an open case gave me a Damaged cell warning right away. So I brought it down and didn't use that one. But later in the day when it was warmer, put it back in & looked at all the stats, cell voltage & what not, it was fine. And have flown it since. Again, it was a cold battery.
The discharger works for P2s and P3s. That's why it's called an "intelligent" discharger. See the review feedback section.
msinger has the same one and uses it too, and he has also recommended it for the P3.
msinger has the same one and uses it too, and he has also recommended it for the P3.
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Very interesting video showing the increased internal resistance of the LiPo at lower temperatures. Taking off with a fully charged LiPo probably enables the LiPo to warm up enough before the critical LiPo internal voltage is reached.
A few weeks?
If it's fully charged, I'd leave it alone.
If it's somewhere between 63% and 87%, I would bring it down to just below 63%
If it's 50% to 63%, I'd leave it alone.
If it's below 50%, I'd bring it up to just over 50%.
MHO
If it's fully charged, I'd leave it alone.
If it's somewhere between 63% and 87%, I would bring it down to just below 63%
If it's 50% to 63%, I'd leave it alone.
If it's below 50%, I'd bring it up to just over 50%.
MHO
OK this is what I do :
General LiPo's do not like being stored at over 70% charge level. In fact damage starts almost immediately but slow. Its accumulative and irreparable. Some claim repair success but its a temporary phenomenon only.
It is recc'd in the LiPo world that storage of LiPo's be made with 3.7 - 3.85V per cell. This roughly equates to 30 - 60% charge level. It is also generally recc'd to err on the lower side of storage than the high.
DJI have created a battery pack that has a built in discharger. This is factory set at 10days idle and then kicks in to bring battery down to about 55% over 2 days. It will then slow and continue to discharge and stop at what is termed Hibernation level ... (so far even DJI haven't actually stated what level that is and its difficult to measure as battery needs waking up to register anything !).
So how do I play the DJI game ?
First I do not worry about full charged batterys. I have 3 and I try to stagger the charge so the discharge occurs different days leaving me at least one pack near full charge if within idle settings.
I like 3 days as my setting - 10 days is too long.
So Charge up and use. I like to land with about 30% on the app showing. This means that battery once switched off and rested will likely bounce back to about 35% - PERFECT storage level for LiPo's.
If I charge up and don't use - I know that 3 days later battery will start auto-discharge to 55% and then slow to lower.
To avoid batterys going low to Hibernation - I like to check every few weeks to make sure at least 1 solid + 1 flashing LED's shwo when checked. If only 1 LED - then I charge fully and let auto do its work again.
Why ? It saves cutting off on estimated charge level - the DJI system looks after the battery for me basically. Going to full as well - gives me confidence that battery is fully capable.
I have a lot of LiPo's .... been using them since first days they took over from NiXX ... and I still have many of the oldies working fine ...
I don't put in the fridge ... I don't do anything special except respect the storage level ...
I do have manual dischargers for DJI as well as all my other LiPo's - but only need them when I don't fly and want to safeguard my 'inventory'.
FInal word - I do not support deep discharge other than to reset the DJI battery Chip counter - as it does not reclaim / repair / rejuvenate / magically create a better LiPo ...
Nigel
General LiPo's do not like being stored at over 70% charge level. In fact damage starts almost immediately but slow. Its accumulative and irreparable. Some claim repair success but its a temporary phenomenon only.
It is recc'd in the LiPo world that storage of LiPo's be made with 3.7 - 3.85V per cell. This roughly equates to 30 - 60% charge level. It is also generally recc'd to err on the lower side of storage than the high.
DJI have created a battery pack that has a built in discharger. This is factory set at 10days idle and then kicks in to bring battery down to about 55% over 2 days. It will then slow and continue to discharge and stop at what is termed Hibernation level ... (so far even DJI haven't actually stated what level that is and its difficult to measure as battery needs waking up to register anything !).
So how do I play the DJI game ?
First I do not worry about full charged batterys. I have 3 and I try to stagger the charge so the discharge occurs different days leaving me at least one pack near full charge if within idle settings.
I like 3 days as my setting - 10 days is too long.
So Charge up and use. I like to land with about 30% on the app showing. This means that battery once switched off and rested will likely bounce back to about 35% - PERFECT storage level for LiPo's.
If I charge up and don't use - I know that 3 days later battery will start auto-discharge to 55% and then slow to lower.
To avoid batterys going low to Hibernation - I like to check every few weeks to make sure at least 1 solid + 1 flashing LED's shwo when checked. If only 1 LED - then I charge fully and let auto do its work again.
Why ? It saves cutting off on estimated charge level - the DJI system looks after the battery for me basically. Going to full as well - gives me confidence that battery is fully capable.
I have a lot of LiPo's .... been using them since first days they took over from NiXX ... and I still have many of the oldies working fine ...
I don't put in the fridge ... I don't do anything special except respect the storage level ...
I do have manual dischargers for DJI as well as all my other LiPo's - but only need them when I don't fly and want to safeguard my 'inventory'.
FInal word - I do not support deep discharge other than to reset the DJI battery Chip counter - as it does not reclaim / repair / rejuvenate / magically create a better LiPo ...
Nigel
Mark ... jokes wearing thin ...
To others - literally any informative Web-site of manufacturers, Battery Techs, LiPO users state storage level of LiPo's as 3.7 - 3.85V.
Nigel
To others - literally any informative Web-site of manufacturers, Battery Techs, LiPO users state storage level of LiPo's as 3.7 - 3.85V.
Nigel
The DJI site says 40% minimum for DJI intelligent batteries. I thought maybe the DJI engineers had a revelation I hadn't heard about. Thanks again.
Perhaps the DJI engineers are influenced by the accounts department. Given LiION will self discharge, albeit slowly and the BMS is comstantly powered (minimal drain but it does use some power) they figured that some users who don’t check the charge level on occasion may inadvertently allow cell damage to occur if starting from a SOC above 40% when abandoning the battery.
I don't understand how a DJI intelligent lipo battery can land at 30% and then go up to 35%. Mine don't do that ever. I also don't understand how a 35% charge can be "perfect" for storage, but at the same time be outside of DJI's recommended charge for storage.
40% is a good practical SOC to allow for some self discharge in storage. Lower is better. If I have a pack at 20% after a flight and I expect to use it in a week or so I don’t bother charging it. I suspect DJI”s guidlines are more aimed at ensuring battery reliability for the less attentive user, as a safety margin.
Your observation is correct, the fuel gauging algorithm in the battery works on available charge accounting for actual load conditions, temp, internal resistance and other factors. The percentage will not increase after a flight. What @solentlife is taking about is voltage, voltage will increase after the load is removed from the battery and it is this resting voltage that is most relavent to storage.
If a cell drips below 2V for a week it will be permanently damaged. Quality cells are fine above 2.5V. DJI packs report 0% at 3V.
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