Incredibly fast battery drain

[DigitalOSH]

Hey guys,
I picked up a P2 with H4-3D used today. Everything on it seems great with one exception. It came with 4 batteries and they all discharge within about 3 minutes. As soon as I get it maybe 20 feet off the ground the P2 starts flashing red and the iOSD shows voltage dipping to ~10.5, then it starts to descend and I can see battery life dropping about 1%/3seconds Here's the stats from them in PT2:

Battery 1:

Full Capacity: 5153
Percentage of Charge: 97%
Discharge times: 16


C1 voltage: 4176
C2 voltage: 4176
C3 voltage: 4176

Battery 2:

Full Capacity: 4800
Percentage of Charge: 5%
Discharge times: 20

C1 voltage: 3831
C2 voltage: 3847
C3 voltage: 3818


Battery 3:

Full Capacity: 5200
Percentage of Charge: 64%
Discharge times: 7

C1 voltage: 3926
C2 voltage: 3936
C3 voltage: 3946

Battery 4:

Full Capacity: 4870
Percentage of Charge: 59%
Discharge times: 25

C1 voltage: 3905
C2 voltage: 3911
C3 voltage: 3918


Looks like the cells are fairly balanced.... yet they all exhibit the same rate of drain. Any suggestions?

 

[Damocleez]

I have a P3 but the nominal fully charge voltage on a standard lipo is 4.2 volts per cell. I flew yesterday in freezing weather and saw reduced flight time by about 30 percent. I have only seen severe battery drain that you are seeing with poorly maintained batteries or bad motors (high drain), using batteries that were allowed to get very cold and then used in cold temperatures and lastly with simply bad or failing lipos. Perhaps others with P2 experience can shed more light on this situation.

By the way, always fly on a fully and freshly charged battery. Anything else is asking for trouble.

 

[Kag49601]

What is the battery life percentage of these batteries? Battery 2 and 4 have cells that are a bit out of sync. Usually they should be within about 5mv of each other. Cold weather will also have an effect as someone else has already mentioned.

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[jason]

Hey guys,
I picked up a P2 with H4-3D used today. Everything on it seems great with one exception. It came with 4 batteries and they all discharge within about 3 minutes. As soon as I get it maybe 20 feet off the ground the P2 starts flashing red and the iOSD shows voltage dipping to ~10.5, then it starts to descend and I can see battery life dropping about 1%/3seconds Here's the stats from them in PT2:

Battery 1:

Full Capacity: 5153
Percentage of Charge: 97%
Discharge times: 16


C1 voltage: 4176
C2 voltage: 4176
C3 voltage: 4176

Battery 2:

Full Capacity: 4800
Percentage of Charge: 5%
Discharge times: 20

C1 voltage: 3831
C2 voltage: 3847
C3 voltage: 3818


Battery 3:

Full Capacity: 5200
Percentage of Charge: 64%
Discharge times: 7

C1 voltage: 3926
C2 voltage: 3936
C3 voltage: 3946

Battery 4:

Full Capacity: 4870
Percentage of Charge: 59%
Discharge times: 25

C1 voltage: 3905
C2 voltage: 3911
C3 voltage: 3918


Looks like the cells are fairly balanced.... yet they all exhibit the same rate of drain. Any suggestions?

Two of those batteries here taken care properly and should be replaced.

 

[DigitalOSH]

Kag49601: These readings were taken indoors, the batteries had been indoors for at least a few hours at that point. What can I do to re-balance these?

Jason: Which ones? Do you mean 2 and 4 as well? Is there anything that can be done besides buying new batteries?

 

[FlyByVideoPros]

Any swelling on the batteries?


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[jason]

Kag49601: These readings were taken indoors, the batteries had been indoors for at least a few hours at that point. What can I do to re-balance these?

Jason: Which ones? Do you mean 2 and 4 as well? Is there anything that can be done besides buying new batteries?

Fully charge all 4 then check each in the P2 software for full and current capacities plus the voltage of all 3 cells . Take a screen shot of all four
and post them If batteries are not maintained properly such as storing with a full charge for a month or more will shorten there usefulness or even look like this. To bad there isn't an easier way to check batteries then having to use the P2 assistant software.

 

[DigitalOSH]

Jason: Here they are

 

[jason]

Jason: Here they are

View attachment 39439 View attachment 39440 View attachment 39441 View attachment 39442

The only one that's good in the newer battery with only 7 cycles the others were not maintained properly. But it is a shame that the only way to check these batteries is to spend the time connecting them to the software.

You should replace all three with OEM replacements and not aftermarket batteries because the price is cheaper.

 

[DigitalOSH]

Hey Jason,
Took them all out on a flight test today. Battery 1 (16 cycles) for some reason gave me 20 minutes of flight time whereas battery 3 (7 cycles) gave me 5m. This doesn't make sense to me. Can you help me decypher this logic?

 

[jason]

Hey Jason,
Took them all out on a flight test today. Battery 1 (16 cycles) for some reason gave me 20 minutes of flight time whereas battery 3 (7 cycles) gave me 5m. This doesn't make sense to me. Can you help me decypher this logic?

Quad need current to maintain flight and plenty of it. Lets look at it from a different perspective. For instants your household electric bill are you being charge by the volts that you use? No. You are being charged by the watt hours you use. Why? Because there isn't a tool or appliance that you own that doesn't use watts or current both being the same thing.

A good example is the screen shot I posted look at the three cell voltages then look at the current values. The P2 had just taken off when those LED's change from green to red so I like you land it and changed the battery. But I did do anything with battery for weeks. When I did decide to check it it had about 60% charge and had the damaged cell warning .so I discharge it to 8% and recharged it.then check it again and you see the results.

 

[DigitalOSH]

I think I miscommunicated what I was getting at. You said:

The only one that's good in the newer battery with only 7 cycles the others were not maintained properly.​

This was battery #3

Yet the one that gave me the most flight time was battery #1

I am trying to figure out why that may be, since it does not follow your theory

 

[jason]

I think I miscommunicated what I was getting at. You said:

The only one that's good in the newer battery with only 7 cycles the others were not maintained properly.​

This was battery #3

Yet the one that gave me the most flight time was battery #1

I am trying to figure out why that may be, since it does not follow your theory

It's not not a theory but I guess you'll just have to find that out for yourself.

 

[DigitalOSH]

I'm not trying to draw your ire here Jason. I'm saying my findings are not adding up with what you suggested and trying to figure out why. Do you have any ideas?

 

[jason]

I'm not trying to draw your ire here Jason. I'm saying my findings are not adding up with what you suggested and trying to figure out why. Do you have any ideas?

One of the problems you have right at the moment is the weather and how long a flight you'll get with each fully charged battery as there's just to many variables involved. When I looked that the full and current capacities of those batteries I picked the one with only 7 cycles for a reason the current valve.
Look these quads do not fly on just voltage it takes current to keep them in the air.

A P2 like mine weighing 1383 grams with a new fully charged battery will fly for 16 minutes and the time starts from the time those props spin up till it lands at 15% battery life. Each time that battery is recharged it will loss a percentage of that current and so goes the flight time. Here's a formula the P2 uses 5.6w and the battery 5.2 mw (5.6w ÷ 5.2a =1.08v)

Without an FPV system and a DVR to record the telemetry on the monitor it's hard to tell what a battery is doing and to try to rely on the crafts LED's when it's down range doesn't make things any easier either.

 

[DigitalOSH]

Ah. I understand. I do have FPV (no DVR) but I can say that when the battery drain starts, the voltage drops to around 10.4 and the screen gets a bit fuzzy. Then battery life drops like a rock (even with the 7 cycle battery but interestingly not with the 16 cycle battery). I concur about weather being an issue, however I did see great 20+ minute performance with the 16 cycle battery. Are the others (including 7 cycle) beyond saving? Should I try multiple full discharges before I just bin them?

 

[jason]

Ah. I understand. I do have FPV (no DVR) but I can say that when the battery drain starts, the voltage drops to around 10.4 and the screen gets a bit fuzzy. Then battery life drops like a rock (even with the 7 cycle battery but interestingly not with the 16 cycle battery). I concur about weather being an issue, however I did see great 20+ minute performance with the 16 cycle battery. Are the others (including 7 cycle) beyond saving? Should I try multiple full discharges before I just bin them?

Well 10.6 is the trigger point on these batteries. Go figure I have two batteries at have 40 some cycles and are 21 months old but only fly for 6 or less minutes. Then there's the with the bad cell which is only 12 months old and of no use. Which this video and the battery I was up at 100' when I notice nice to have a DVR record.

 

[FlyByVideoPros]

In my experience, leaving a battery charged for more than 50% for a long period of time will result in swelling, or cell damage, which can cause seriously fast draining. Keeping the batteries discharged under 25% has solved this issue. In addition, like he said before, lots of factors effect battery drainage. Device usage, wind, stick movement, and temperature being the main ones. Someone made a cool device the powers a light with a P2 battery for discharging. Saw it in YouTube. We just make sure we use up power while we are flying.


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