Curious case of the Inspire Battery: You are only as strong as your weakest cell.

The photos included in this report are pretty self-explanatory. But you'll notice that the flight started with a cell that was a bit lower than the rest. The craft flew normally for a little over 12 minutes...but when the weak cell drained below the rest into the red zone...the craft went into auto-land. This might explain why the battery seems to be fine....then suddenly it goes into critical (auto-land) mode. I think watching the battery cell condition may be an important part of flying. The main battery readout may be deceptive....until one of the cells goes into the red zone. Also notice that between the time of the last 2 photos...the charging cycle went from 9 charges to 10 charges. There were no charges. I haven't attempted to recharge the battery yet....since it is not yet at room temperature.

This is exactly why dji should put a warranty of at least 1 yr on their batts, this is almost certain a production error. Looks like a loose connection with that specific cell.

I sure hope limefuel starts making inspire batteries soon!

WOW that's crazy.

I just recharged this same battery. It charged normally...and it says 100%...but look at the individual cells.

I just got this answer from DJI:
Dear pete,

Thank you for contacting DJI Technical Support.

I checked your picture and the part you concern is not the battery capacity, it is the voltage of Battery Cells.
It is normal that the voltage of Battery Cells are different.
Do all the drone function well?

Thank you for choosing DJI.

Best Regards,

DJI Product Application Technical Support

Office hours: Monday to Friday , 9:00AM to 18:00PM (HongKong Time GMT+8:00)

Surprising.....I thought that this is exactly the thing to avoid with lipo batterys. Do they really have formed people's in the technical support or is it a problem with the language? Sometimes I think they use the google translator........

Your battery is clearly defective. I'd refrain from using it again and get it replaced under warranty.

Anyone with common rc knowledge can tell you that it's defective. as soon as one cell is draining faster and can't get charged to 99% of it's capacity it is defective. And this should not happen for a very long time under normal usage. I use my rc batts 2-3 hrs a week for almost 2 years before they begin to fail! Try to get them replaced. If the cell runs out in flight it could turn off the power and you'll lose much more than just the battery (fingers crossed).

I guess it's a matter of getting DJI to do the right thing. It seems terribly irresponsible of them.

pete1144@me.com Posted at 2015-3-18 23:13
I just got this answer from DJI:
Dear pete,

It's normal for a defective battery to have a weak cell. That guy is trying to sell you a bill of goods! It has a defective cell that won't balance. What a stupid thing to say!

pete1144@me.com Posted at 2015-3-18 23:13
I just got this answer from DJI:
Dear pete,

Pete where are you located?  I noticed you got through to China.  

USA..Orlando, FL. I sent an email query into the dji USA.

No doubt this pack is not airworthy and should not be flown.
This pack has a bad cell, it happens, even in higher end lipo cells.
DJI should swap it out asap then establish some kind of return plan with their pack manufacturer.
One thing I can say for sure, it's bad idea to fly with a bad cell on a $100 foamy much less a 4k bird.
ANYONE who notices a bad cell on any of their packs should immediately ground the pack.

The battery has been marked and grounded.

Electronics 101. The voltage moves the current that does the work.

So here is the latest in the saga of dealing with DJI. This is from the chat line.
Sending file  Batt3.PNG
"Batt3.PNG" Sent succeeded.
Sending file  Newly charged_100%.jpg
Sent failed:uploading is unsuccessful :002
Sending file  Batt5.PNG
"Batt5.PNG" Sent succeeded.
17:03:

me:One of the cells does not fully charge. I have photos.
17:08:18
DJIk,sirYour battery is faulty
Damage of batteries
Me:Yes...we agree on that
DJIlease don't use
Me:I have put it away...then reported it to you.
17:10:04
I give you a contact information
Thank you
You contact them, change new one
That sounds very fair to me.
17:11:35
Dear Customer,
Thank you for contacting DJI Technical Support.
In order to provide you with the fastest and most effective service, our Support Team in LA is taking charge of the after-sales service for customers from North America. If you need any support concerning the product, please feel free to contact our North American regional office for help.
The contacts of our North American regional office are as follow:
Email: us.support@dji.com
Phone: +1 (818) 235 0789
Mon-Fri 9:00 am - 5:00 pm (PST)
We apologize if this change has caused any inconvenience to you and really appreciate your understanding and cooperation.
Thank you for choosing DJI.
Best Regards,
DJI Support Team
Me:So what do I do now? Call them?

Hi Pete,
Your email was not from US team, please note the time zone info at the signature, it listed HK time. May I ask what email address you emailed to?

As the online chat suggested, yes, please call our US center, they should be able to help you.

Thank you

Thank you for your reply. I sent an email to US support and they returned an email. We'll see what's next.

Please keep us posted, I think I am having a similar issue