Sorry I thought I had tried to help- my other commentary was tongue in cheek. Stick the battery in your AC powered up and have a look what the individual cell voltages are. Also tell us the charge level (%remaining) and total capacity reported.
Battery Retirement Poll
- Thread starter John Locke
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Yep! The wife gave her that name in memory of Judy Garland after my P4 looked like it was heading to Kansas one time.....
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I have two batteries that are at 84% life left (per airdata) and only get about 14-15 min flight times and I've also noticed that the last couple of flights when I'm done the batteries are getting swollen some and go back to once cooled off. Should I stop using these batteries?
Swollen batteries are not a good thing they can burst and catch fire, they are not recommend for use by DJI
I have been flying LiPo powered RC planes awhile and have been fortunate enough to learn from my own and other's mistakes (rolling eyes) since about 2001. Here are a few other tips to help your batteries performance and longevity that should apply to DJI's LiPo's as well.
1-First and foremost is to treat each pack and each cell like a roman candle that may go off at any time, especially if the tinfoil cell is punctured or if there is a short in the wiring for any reason, like water getting in the pack. And especially more violently if it is full charged. Even DJI cells and packs aren't all perfect, but they are high quality for the most part from what I have seen. Many RC packs have simply a thin piece of tape (!) between the cell pack tabs/soldering/wires keeping them from shorting. I have not had a DJI pack apart, but I have a feeling that it is not the case since there are cooling slots between the 4 cells, which is awesome. And if they are charged incorrectly or overcharged or the charger malfunctions, get out some popcorn because there will be a show!
Having a safe place to charge/store the packs is a great idea. An ammo cannister or safe bag for transport are smart. At home or in the shop a little setup of cinder blocks or ceramic tiles or even a sturdy thick metal box for a charging area is not convenient, but it is smart. Just imagine igniting a roman candle inside of it. Would anything nearby catch on fire? That's what mindset you'll need. Ask any RC flyers how many guys they have heard of whose house or shop burned down in the early days of Lipo's. It's been a lot. I would never recommend putting a Lipo on a charger and leaving the vicinity. You may not like what you find when you return.
2-When you have discharged a pack and it is still warm at all, let it cool completely on it's own before putting it on the charger.
3-Extreme heat and cold are not friends of Lipo's. Keeping them out of the sun helps too. When you are flying, extremely high discharge for any length of time kills packs. They tend to overheat when this happens. Avoid being at full throttle unless absolutely necessary. When you land the packs should be a little warm maybe up to 130'F or 140'F as a guess or so but not hot. We had some packs from pylon planes that were too hot to hold in your hand, they didn't last many flights, but that was what racing was all about.
4- When you are charging, if possible, it doesn't hurt to have a small fan on the charger and batteries to dissipate some heat. Also, when the Phantoms are turned on, they are designed to have proper cooling when the blades are moving, but if you remove the blades for testing or whatever, a lot of heat builds up in the battery and body. Having a small fan on it is not a bad idea to move some air around it.
5- Like mentioned earlier, letting a pack sit fully charged is not good for the life of the pack. Once you pull a pack off the charger, the clock is ticking. Sometimes you have to cancel flying. Stuff happens. Either fly it or decide how long before you'll use. If it's just overnight, it might not be too bad, but I like to discharge it just a little. If it's going to be a few weeks, find a way to discharge it down to near it's nominal voltage.
I'm fairly new to DJI equipment, but that's the best of my Lipo knowledge I can bring to the DJI table, but like many things, wait a few weeks and some of it may be proven incorrect, lol.
By the way, does anyone have any methods of discharging the P4 batteries that's better than putting them in the aircraft?
1-First and foremost is to treat each pack and each cell like a roman candle that may go off at any time, especially if the tinfoil cell is punctured or if there is a short in the wiring for any reason, like water getting in the pack. And especially more violently if it is full charged. Even DJI cells and packs aren't all perfect, but they are high quality for the most part from what I have seen. Many RC packs have simply a thin piece of tape (!) between the cell pack tabs/soldering/wires keeping them from shorting. I have not had a DJI pack apart, but I have a feeling that it is not the case since there are cooling slots between the 4 cells, which is awesome. And if they are charged incorrectly or overcharged or the charger malfunctions, get out some popcorn because there will be a show!
Having a safe place to charge/store the packs is a great idea. An ammo cannister or safe bag for transport are smart. At home or in the shop a little setup of cinder blocks or ceramic tiles or even a sturdy thick metal box for a charging area is not convenient, but it is smart. Just imagine igniting a roman candle inside of it. Would anything nearby catch on fire? That's what mindset you'll need. Ask any RC flyers how many guys they have heard of whose house or shop burned down in the early days of Lipo's. It's been a lot. I would never recommend putting a Lipo on a charger and leaving the vicinity. You may not like what you find when you return.
2-When you have discharged a pack and it is still warm at all, let it cool completely on it's own before putting it on the charger.
3-Extreme heat and cold are not friends of Lipo's. Keeping them out of the sun helps too. When you are flying, extremely high discharge for any length of time kills packs. They tend to overheat when this happens. Avoid being at full throttle unless absolutely necessary. When you land the packs should be a little warm maybe up to 130'F or 140'F as a guess or so but not hot. We had some packs from pylon planes that were too hot to hold in your hand, they didn't last many flights, but that was what racing was all about.
4- When you are charging, if possible, it doesn't hurt to have a small fan on the charger and batteries to dissipate some heat. Also, when the Phantoms are turned on, they are designed to have proper cooling when the blades are moving, but if you remove the blades for testing or whatever, a lot of heat builds up in the battery and body. Having a small fan on it is not a bad idea to move some air around it.
5- Like mentioned earlier, letting a pack sit fully charged is not good for the life of the pack. Once you pull a pack off the charger, the clock is ticking. Sometimes you have to cancel flying. Stuff happens. Either fly it or decide how long before you'll use. If it's just overnight, it might not be too bad, but I like to discharge it just a little. If it's going to be a few weeks, find a way to discharge it down to near it's nominal voltage.
I'm fairly new to DJI equipment, but that's the best of my Lipo knowledge I can bring to the DJI table, but like many things, wait a few weeks and some of it may be proven incorrect, lol.
By the way, does anyone have any methods of discharging the P4 batteries that's better than putting them in the aircraft?
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Why are you storing your batteries in the fridge? That is very bad from what I have read. They should be stored at room temperature, ~20 C or ~66 F at around 60% charge.
Pinnacle: Just use built in discharge method. Mine is set at 2 days. I dont let it discharge inside the Phantom.
Pinnacle: Just use built in discharge method. Mine is set at 2 days. I dont let it discharge inside the Phantom.
You have read wrong- lipo chemistry can sustain -40seg C without harm in storage. Also, I am unsure how you arrived at 68% as the storage level, it has been demonstrated that 40% SOC is the ideal storage level to minimise capacity loss while storing lipo packs.
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Ok, good to know!
How come DJIs auto-discharge do not discharge to 40% if thats the better level?
Presumably DJI’s intent in implementing the Auto discharge is primarily to minimise warranty claims and increase safety- it is well known that LiIOn chemistry is least stable when at full charge and that packs loose capacity more quickly when kept at full charge. What is less frequently understood is that allowing a cell to fully discharge is almost certain death. Given charge level is constantly decreasing over time setting the auto discharge termination voltage in the higher side is likely to allow for a user leaving the packs for several months and having them not reach critical low voltage.
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Yeah, how come people are doing these "deep cycles" and discharge their batteries to like 1-5%?
I never do that. I stop flying at around 15% capacity.
That full depletion and recharge routine is often recommended (by manufacturers other than DJI) and more broadly as a means of recalibrating the smart electronics that report capacity, level and health. As far as the lipo cells go there is no benefit. It is no longer recommended by DJI.
What is your definition of "fully discharge". Are you talking 0% in Go, or 3.00V actual?
I was talking in the context of a pack left unattended and the potential for self discharge to reach a level where permanent damage (increased and irreversible IR increase) occurs, we might say 3V would be a conservative resting voltage in these circumstances with 2.7V being almost certain death for most lipo chemistry. As far as the often followed fly to 0% or shutdown for DJI packs the battery will power down above critical low voltage- another smart battery safety feature.
Yeah, agreed, but I believe DJIs smarts in their battery won't allow the battery to be below 3.3V or somewhere in that neighborhood, while flying. If I recall, in a P4 at 0% in the Go4 app is around 3.3V isn't it? However, I'm pretty sure DJI still has the auto-off enabled at 3.00V, which seems risky.
Many of us remember the P3P's falling form the sky with 1.5 firmware in Dec 2015 right? That's because their "intelligent battery" turns off at 3.00V, regardless of the flight status. Is that intelligent? My information from DJI (at CES, which sometimes you can't believe) personnel said that their 3.00V shut off routine is to prevent the battery from draining below 3.00V if you accidentally leave the craft turned on overnight, as a protection scheme. I told them that's fine if the craft is not moving. I suggested the battery should only be allowed to shut down if it's not moving. But they said that's impossible (I don't believe that) to do, claiming the FC can't talk to the battery, providing permission to shut down to the battery. So DJI elected to put a governor on the throttle in FW version 1.6 after the battery cells discharged down to 3.6V, at which time you didn't have full power in the P3P. That was their fix to mitigate high throttle scenarios (full forward throttle right stick + full ascend throttle left stick) from taking the battery down to 3.00, triggering shutdown. This mid-flight power shutdown protection with craft falling (excellent protection, right?) from the sky happened mostly in cold climates, it was a rarity in warm (greater than 60F) weather areas. Today with bigger batteries DJI doesn't see this problem at all anymore, and their 0% battery level in Go4 is way above 3.3V, way out of reach of getting down to 3.0V, which can trigger auto-shut down if reached.
The trick is to monitor your voltages in flight and land prior to getting close to critically low. DJI implementing the propulsion output limitation in an effort to avoid LVC was an awesome improvement to the flight logic. If the LVC wasn’t implemented in the smart battery firmware we would see batteries with cells damaged beyond repair. Yes, risking a damaged pack may be preferable than total shutdown in flight however it is easy to avoid in practice. No matter what the limits are people will always manage to find them.
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