P4 Battery Issues!! need technical help

[dclark]

forgive me, I'm new to this forum..
I have a phantom 4 with 2 batteries. One of the batteries says its full but won't power up the aircraft. upon closer inspection, I found that the 4 positive leads were all putting out 2.10Vdc each using my multimeter.

I bought the battery off eBay and cannot return it, or send it back for warranty.

any help would be greatly appreciated,

 

[Erised]

Providing your readings are correct, fully charged you should have around 4.2 v per cell . Lipos' that go under 3v per cell may have unrecoverable damage, I would send it back for warranty.

 

[Jayfdee]

I think the battery is terminal. Ebay has many non OEM batteries, and most users on this forum would be very wary buying on ebay, even more so if it was a used battery. However why can you not return, or take a case out against the supplier.
If the cells are only putting out 2.1V then it has been discharged too much and will not recover.

 

[DanMan32]

P4 batteries give you access to the individual cells? If not, the 2.1v doesn't indicate the state of the cells themselves.

 

[dclark]

P4 batteries give you access to the individual cells? If not, the 2.1v doesn't indicate the state of the cells themselves.

I believe Im reading each individual cell as per the pinout on the bottom of the OEM charger which reads NC--++++--NC. I assumed that each of the positive leads is would be a separate cell seeing as there are 4 positive leads as well as 4 cells...

 

[dclark]

Has anyone successfully taken a phantom 4 battery apart without damaging it?

 

[dclark]

I think the battery is terminal. Ebay has many non OEM batteries, and most users on this forum would be very wary buying on ebay, even more so if it was a used battery. However why can you not return, or take a case out against the supplier.
If the cells are only putting out 2.1V then it has been discharged too much and will not recover.

The seller is sending me a replacement and is not requiring that I send the old one back (usually indication that its a nonOEM battery).. I'm a technical minded person and I'm curious to see if I can fix this battery

 

[K9VXV]

Good luck. I'd be afraid to put a non OEM DJI product in my Phantom. On my Phantom (except props) different story. Let us know how it performs? What was the price?

 

[DanMan32]

I believe the P4 batteries use the same concept as P3 but different formfactor. 4 pins are probably to handle the current. I would bet you will get zero ohms between + pins meaning they are all connected. All the charger does is provide a fixed voltage for the battery electronics to use to do a controlled charge of the lipos.

 

[dclark]

I believe the P4 batteries use the same concept as P3 but different formfactor. 4 pins are probably to handle the current. I would bet you will get zero ohms between + pins meaning they are all connected. All the charger does is provide a fixed voltage for the battery electronics to use to do a controlled charge of the lipos.

I agree, the cells are equalized and thus have consistent voltage readings across all 4 leads. Ill check the resistance across all POS as well as the 4 NEGs and get back .. I wish I can find information about how to properly dismantle this battery. The likelihood is, I'll never put this into my aircraft again, just curious

 

[Extra330]

I find it somewhat odd that all 4 cells would read the exact same voltage. I would expect a small deviation even in a fairly well balanced pack. Lipo's need to be managed because you can't have any one cell get behind in charge. This is why a balance charger is necessary in normal hobby lipos. The phantom battery itself has this balance circuit built in. I have brought regular lipos back by supplying a charge to individual cells until they are up enough for Lipo charger to take over, although ultimately it was a scientific/educational endeavour. You could tear that battery apart and likely bring it back. That being said, the eventual outcome could likely be your house burning down, or a quick uncontrolled "landing" from 200'. There is no scenario where I would risk even a slightly suspect battery in my aircraft. Dispose of it properly and don't look back, as you don't even want that compromised pack sitting in your home.

 

[dclark]

I find it somewhat odd that all 4 cells would read the exact same voltage. I would expect a small deviation even in a fairly well balanced pack. Lipo's need to be managed because you can't have any one cell get behind in charge. This is why a balance charger is necessary in normal hobby lipos. The phantom battery itself has this balance circuit built in. I have brought regular lipos back by supplying a charge to individual cells until they are up enough for Lipo charger to take over, although ultimately it was a scientific/educational endeavour. You could tear that battery apart and likely bring it back. That being said, the eventual outcome could likely be your house burning down, or a quick uncontrolled "landing" from 200'. There is no scenario where I would risk even a slightly suspect battery in my aircraft. Dispose of it properly and don't look back, as you don't even want that compromised pack sitting in your home.

 

[dclark]

actually there is a slight variation with in +- a fraction of a volt amongst the 4 positive leads.. you are quite the wordsmith, at this point, Im convinced that disposing of the battery is the proper thing to do.thanks

 

[Extra330]

Absolutely the best choice. These darn things are so expensive, it's very tempting to entertain bringing them back.

 

[DanMan32]

You could keep the battery for non-flight purposes such as simulation, downloading flight data, alignments, etc.

 

[DanMan32]

I would be really surprised the individual pins are isolated to each cell since all the intelligence is in the battery's electronics and not in the charger. The charger is just a simple high current constant DC voltage supply.
Unless the AC is using it rather than the battery electronics reporting it.