Two of my three Mavic Air batteries are showing "Battery Signal Error".
The Air's status light is a solid red, "Critical Error", when used in the aircraft.
The charging dock displays a red light and no longer charges the defective batteries, though I can fully charge them direct from the charger. (There have been solid red lights on the dock in the past but reseating the batteries got rid of the problem and they charged successfully.)
There is no apparent damage to the defective batteries, all pins are present, straight and clean.
I have downgraded and upgraded the firmware DJI Assistant 2 using my good battery, but every attempt to refresh/upgrade/downgrade with the defective ones fails with "Battery power level must be greater than 50%. Recharge battery and retry.", presumably because the app does not know the actual battery charge level. A couple of pictures of screen shots below from the Go4 app, the first showing displays from the defective battery followed by the displays from the remaining good battery.

Why did this happen?
Is it likely to happen to my remaining good battery?
Is there anything that can be done to recover the defective batteries?

Any help or advice is welcome.

Thanks

Hi, I'm sorry to hear about the issue that you are experiencing. Please kindly contact our support to start a case and send it in for diagnosis: https://www.dji.com/support. Thanks!

DJI Diana Posted at 2018-4-20 23:41
Hi, I'm sorry to hear about the issue that you are experiencing. Please kindly contact our support to start a case and send it in for diagnosis: https://www.dji.com/support. Thanks!

Thanks DJI Diana, sorry for the delay in my response.

Case has now been opened with the repair centre, awaiting shipping label. Hopefully things will go smoothly!

Gimbali Posted at 2018-4-26 01:47
Thanks DJI Diana, sorry for the delay in my response.

Case has now been opened with the repair centre, awaiting shipping label. Hopefully things will go smoothly!

All right! Should there are any further questions, feel free to contact us.

I had my two batteries replaced and managed to get in a few flights in the week since they were delivered. Great to be able to fly three batteries at a time again!

Thanks DJI Netherlands for a quick and efficient service!

Gimbali Posted at 2018-5-17 02:09
I had my two batteries replaced and managed to get in a few flights in the week since they were delivered. Great to be able to fly three batteries at a time again!

Thanks DJI Netherlands for a quick and efficient service!

We are pleased to hear everything turns out to be great, enjoy it and hope you have a good time on flying the drone, we will keep up the great works.

same things happen to me !!
how ?

cLoud.R Posted at 2018-5-24 04:19
same things happen to me !!
how ?

I have no explanation as to how or why it happened.
All I can suggest is that you open a ticket with dji and get the faulty battery or batteries replaced, as I did.

I hope you get the problem resolved  and are up and flying again soon!

cLoud.R Posted at 2018-5-24 04:19
same things happen to me !!
how ?

Sorry to hear this. Please try to discharge the battery fully and re-charge the battery fully again to check whether the warning remains or not. If still no luck, please kindly refer above and send the battery in for diagnosis if it is still under warranty period.

Hello am having similar issue here

My battery Mavic Air,  Battery Signal Error

I'm having the same problem, I want to get a DJI refresh but it's not available here in Philippines. Please DJI help me about this.

Please DJI help me about this. My Item is new I order this on lazada web site. last November 7, 2018 I received the Drone.

Richie Ian Sobejana Posted at 2-12 17:47
Please DJI help me about this. My Item is new I order this on lazada web site. last November 7, 2018 I received the Drone.

Your battery should be still under warranty,  you shouldn't need dji refresh to get it repaired or replaced.
Use this https://www.dji.com/support. to raise a ticket and dji will instruct you through the process.
Good luck!

Kas Posted at 2-13 01:31
Your battery should be still under warranty,  you shouldn't need dji refresh to get it repaired or replaced.
Use this https://www.dji.com/support. to raise a ticket and dji will instruct you through the process.
Good luck!

Thanks, Kas
I already send my concern on DJI until now I'm waiting for there reply. I that normal that they don't reply right away?

Richie Ian Sobejana Posted at 2-14 00:16
Thanks, Kas
I already send my concern on DJI until now I'm waiting for there reply. I that normal that they don't reply right away?

You're welcome!

Give them a few days to look over your ticket and they will reply soon after.

Richie Ian Sobejana Posted at 2-14 00:16
Thanks, Kas
I already send my concern on DJI until now I'm waiting for there reply. I that normal that they don't reply right away?

Hi Richie, sorry for the late response. Currently, DJI Care Refresh is not available in the Philippines. Also, may I have the ticket number or email address when you contacted our support? We'd like to check the current status and help you get an update soon.

djiuser_ZZzQWbJT6Ly5 Posted at 2-12 11:59
Hello am having similar issue here

Hi there, please kindly refer to 9# and see whether it helps. Alternatively, you may contact the dealer help to send the battery in.

Attached is the reason (at least in my case) of "Battery Signal Error" message. A small resistor with "100" written on top (checked on working battery) is burned away. Will replace it soon, hope this will solve the issue.