Critical voltage warning.

robinb · Nov 28, 2015

2nd flight and 2nd battery I was at just over 40% battery power and I started getting critical voltage warning.
And it started to auto land. (1st warning is set to 30% and second at 15 or 20%)

This battery has only had 8 cycles.

I was climbing at full throttle at the time. But before that had been flying gently.

Battery was very secure and locked, i alway check and also checked once it had landed.
Latest firmware/software as of this week on advanced.

Here are the healthy drone logs, any thoughts ?

TheRealNick · Nov 28, 2015

robinb said:
2nd flight and 2nd battery I was at just over 40% battery power and I started getting critical voltage warning.
And it started to auto land. (1st warning is set to 30% and second at 15 or 20%)

This battery has only had 8 cycles.

I was climbing at full throttle at the time. But before that had been flying gently.

Battery was very secure and locked, i alway check and also checked once it had landed.
Latest firmware/software as of this week on advanced.

Here are the healthy drone logs, any thoughts ?

View attachment 36719 View attachment 36720 View attachment 36721

Based on the voltages at start it looks like you did not start with a fully charged battery, is that correct?

robinb · Nov 28, 2015

Correct, just doing some very short range flights.

TheRealNick · Nov 28, 2015

robinb said:
Correct, just doing some very short range flights.

From my reading here it seems like taking off without a fully charged battery results in frequent autolands due to critical battery warning. I plan to only start with fully charged batteries to avoid....which I also recommend...

robinb · Nov 28, 2015

Yes, i would normally do the same but through a combinations of weather and other distractions my batteries started to auto discharge as not flown for couple of weeks.
So it was a bit of a rush today to enjoy some good weather and forgot to put them on charge.

What surprises me i was seeing over 40 % at all times but seeing a critical warning and auto land.

ViperNuke · Nov 28, 2015

How long was that battery not fully charged?? More than 24 hrs?? If so that's why you getting the voltage error.. Make sure you always fly with 100% charged battery.. You can still fly with partially charged battery on the same day of it being fully charged....

alokbhargava · Nov 28, 2015

It's not that one can start flying with 50% charge as that has enough juice for at least 5 minutes before one should start planning landing. I see two problems: 1. 5 minutes passes quickly and one is mentally not prepared to land. 2. The discharge characteristics of a battery with 100% at start is different than 50%.

Wacker2611 · Nov 28, 2015

Golden rule is never fly with depleted batteries if they've been left for a day or two. If you're flying the same day you should be fine, but no longer than 24 hours or you're asking for trouble.

robinb · Nov 28, 2015

ViperNuke said:
You can still fly with partially charged battery on the same day of it being fully charged....

I have never heard that before.

It was only a 5 minute flight and what I dont understand why its saying critical at over 40%

robinb · Nov 28, 2015

alokbhargava said:
5 minutes passes quickly and one is mentally not prepared to land. .

Did you have an FC40, 5 minutes was about the max flight time ?

alokbhargava · Nov 28, 2015

If you stop using a battery for certain time ( not sure how many hours), it internally recovers to some extent and the next discharge curve will be different than the fully charged discharge curve. You might get wrong warning, who knows it may be correct?

Please note that the percent remaining charge readings that you see on App are all calculated values based on a defined discharge characteristic and may vary on the health of the battery. The true juice in the battery is seen if you monitor cell voltages and the lowest cell voltage. Battery suddenly dies if the voltage level is below a value. These are not linear related values. Sorry it's difficult to explain.

TheRealNick · Nov 28, 2015

Check my explanation here....
Phantom 3 Pro Catastrophic Battery Failure | DJI Phantom Forum

TheRealNick · Nov 28, 2015

I do not know exactly how the phantom algorithm works but my guess is it will autoland when any 1 of the cells reaches some min voltage. For the percent my guess is current integration and a state of charge table. As a result I would watch both the percent and the lowest cell voltage. The cell voltage will drop much faster on subsequent flights on the same charge.

Oso · Nov 28, 2015

It's remarkable how many times in the last month or so that we have seen questions about critical battery levels and flying with batteries that have already auto discharged. I don't recall seeing so many questions and posts on that exact topic until recently. I wonder why SO many all of a sudden. Any thoughts as to why that may be?

alokbhargava · Nov 28, 2015

It's not just battery, every question is asked again and again. I think that's the way forums usually run.

Oso · Nov 28, 2015

For sure I agree that the same questions are asked and answered countless times. This particular one however, the sudden critical battery warning, seems like it hasn't been beaten to death until perhaps the last month. It seems to come up several times per week now. I'm just curious why now?

alokbhargava · Nov 28, 2015

I think new people don't do their homework first.

Oso · Nov 28, 2015

alokbhargava said:
I think new people don't do their homework first.

Again I agree big time, and we will see much more of that about a month from now!

Still, this critical battery issue seems too out of the blue and reported too much in a short time. For some reason it just feels to me that something happened or changed about a month ago that is now driving the increased reports. Maybe I'm just imagining it. We'll see I guess. Cheers!

MattyDread · Nov 28, 2015

robinb said:
Yes, i would normally do the same but through a combinations of weather and other distractions my batteries started to auto discharge as not flown for couple of weeks.
So it was a bit of a rush today to enjoy some good weather and forgot to put them on charge.

What surprises me i was seeing over 40 % at all times but
seeing a critical warning and auto land.

Rushing & not starting with Fully charged batteries (as per Dji reccomendation) means you will probably crash at some stage..

MattyDread · Nov 28, 2015

Oso said:
Again I agree big time, and we will see much more of that about a month from now!

Still, this critical battery issue seems too out of the blue and reported too much in a short time. For some reason it just feels to me that something happened or changed about a month ago that is now driving the increased reports. Maybe
I'm just imagining it. We'll see I guess. Cheers!

Oh yes!!! STRAIGHT out of the box - fire her up, forward, zoom...Crash.!!! The xmas numpties zooming around at full pelt on day 1 hahaha
Without reading anything...