Low cell voltage..

[Pedro]

Just noticed one cell struggling a little. It's only had 22 charges but I guess I should bin it..?

I've not tried a total discharge with it yet but at 50% charge the cell differential was down to 0.03v.

 

[Cyberpower678]

Yikes, that's off, and it will only get worse if not balanced. You should try to slowly discharge the battery entirely and then recharge it.

 

[BD0G]

Big difference there. I read somewhere that DJI warranties the batteries up to 100 charge cycles.

It may be factual and worth a shot by contacting DJI.

 

[Former Member]

DJI warranties the batteries up to 100 charge cycles

And/or up to 6 months. Dont toss it in the bin it if it's less than 6 months old. Send it back to DJI and they will send you a brand new one.

 

[Pedro]

Thanks but it is over 6 months old..

I'll try a discharge to 0% (whatever voltage that is with these) and charge it up again a couple of times but I won't fly with this unless it sorts itself out.

 

[Cyberpower678]

Thanks but it is over 6 months old..

I'll try a discharge to 0% (whatever voltage that is with these) and charge it up again a couple of times but I won't fly with this unless it sorts itself out.

Make sure to discharge slowly. Rapid discharging my result in a voltage dump in the third cell and then you can most certainly toss it out.

 

[Cyberpower678]

But as a side hobby I was thinking about taking dead batteries, or bad batteries, and dismantling them to put new more powerful cells in them, and the reselling them. I'm a dreamer, but if I can raise the batteries Wh to 99.9, which is the absolute upper legal limit allow to be taken on a flight, then I can increase the flight time to up to 60 minutes or even more on a single charge.

So if you want to get rid of yours and send it to me, or @Thunderdrones, feel free to.

 

[Pedro]

As the old adage goes, you can't fit a quart into a pint pot.. Upping the stock 43.6 Wh to 99 in the same form factor just ain't going to happen, yet.. I'm sure it will as battery technology advances.

I'm still not 100% convinced this one isn't salvageable, 0.11v disparity is bad but not disastrous. I'll give a few cycles and see what happens.

 

[Pedro]

Oh well, that didn't work, in fact it made it worse..

 

[Cyberpower678]

Oh well, that didn't work, in fact it made it worse..

View attachment 28791

If you dismantled the pack wired up some leads to the correct terminals and tried a balance charge, that might do it.

 

[Cyberpower678]

Even worse is that now your drift is 0.15V and it shouldn't be more than .03V

 

[BD0G]

Figure out if the battery has had less than 100 total charges and if so approach DJI with the idea of swapping it out for a new one. Even if it is older than 6 months. "Dont bin it bro"

 

[Pedro]

Figure out if the battery has had less than 100 total charges and if so approach DJI with the idea of swapping it out for a new one. Even if it is older than 6 months. "Dont bin it bro"

Thanks, I'll give it go but won't hold my breath..

 

[BD0G]

Thanks, I'll give it go but won't hold my breath..

Squeaky wheel gets the ...

 

[Pedro]

Squeaky wheel gets the ...

Well.. I may just end up owing you a beer or two the next time you're in the UK.

I put in a repair request, described the symptoms, informed them when the battery was purchased and I've just received a UPS shipping label to send it back.. Watch this space.

I was all for pulling it apart to see if I could replace the cells.

 

[BD0G]

They will inspect it and if they deem it within warranty you will receive a replacement.
Ive got my fingers crossed for ya.

 

[Cyberpower678]

Well.. I may just end up owing you a beer or two the next time you're in the UK.

I put in a repair request, described the symptoms, informed them when the battery was purchased and I've just received a UPS shipping label to send it back.. Watch this space.

I was all for pulling it apart to see if I could replace the cells.

The cells may not need replacing, just rebalancing, charging and discharging cells without balance just unbalances it even more until the cells either die or catch fire from over discharging.

 

[Pedro]

The cells may not need replacing, just rebalancing, charging and discharging cells without balance just unbalances it even more until the cells either die or catch fire from over discharging.

Surely the in-built charger circuit in the batteries balance charge already? I can't believe that DJI would build a lipo without this function..

 

[Cyberpower678]

Surely the in-built charger circuit in the batteries balance charge already? I can't believe that DJI would build a lipo without this function..

I honestly have no idea if they do or not. LiPos normally hold a balance on there own unless slightly off which ends up drifting further and faster over time. Given that they already push LiPos to 4.3V instead of the max 4.2V, I'm not sure what their safe practices on LiPo safety is.

 

[Pedro]

They will inspect it and if they deem it within warranty you will receive a replacement.
Ive got my fingers crossed for ya.

You can un-cross your fingers now BD0G and I owe you a beer or two..