Mavic turned off suddenly

[SpitFire]

Nice that you can still laugh about the loss of the drone.
I never allow anyone to fly my birds, on my preflight check list is a reminder that battery is 100% charged, that the Ipad battery is 100% charged,
and the RC battery is 100% charged. Its a rule of thumb over the years.
Like, making sure the gas tank of your car is filled up before a long trip.

 

[Nes]

Following this thread with interest. My question to the knowledgeable contributors here is.. given that cell 2 on the battery dropped away when the load came on, in theory would this still have been able to happen had the battery had a much higher rate of charge remaining at take off.

Tks

 

[DanMan32]

That's what to me is uncertain. If the battery were fully charged, I'd be more certain if the cells were balanced or if cell 2 was dragging from get go.

I agree it's most likely cell 2 has gone bad, but I believe there's some possibility that an auto discharge occurred, left cells a bit out of balance putting cell 2 at a disadvantage, which got worse as the SoC diminished during flight.

 

[slup]

...given that cell 2 on the battery dropped away when the load came on...would this still have been able to happen had the battery had a much higher rate of charge remaining at take off.

We have seen many cases on this forum where even batteries being on 100% charge at take off have had cell failures with voltage dropping like rocks well below the 3V forced autoland limit shortly after take off ...

Common factors have nearly exclusively been either old batteries, batteries not cared for properly, not monitored performance wise, pilots not thinking that batteries is consumables ... or a combination of these factors.

This particular battery was over 3,5 years old ... it's apparent that the OP most probably didn't had knowledge about that this could happen & that batteries don't last for ever (as he was clueless & couldn't understand what just happened and couldn't read out the obvious from the Airdata views). With this said, I don't think the battery performance trends was followed either ... & I doubt that the battery have been cared for meticulously in the past.

Above may sound harsh ... but think that the cases here at the forum show that it's pretty common that pilots lack knowledge about batteries, if they take charge to 100% all is good ... they fly until they are taken by surprise with a forced autolanding.

Think it's proper that the OP treat his friend with a bit of understanding ... he borrowed out worn out equipment, this had happened sooner or later anyway.

 

[DanMan32]

I agree that battery health is most likely culprit, but we've also seen where flying right during, or perhaps even after auto-discharge has caused similar symptoms and so we've concluded one should avoid flying without a fully charged battery, especially if it has undergone self-discharge.