Been waiting months to get legal, as a result the Mavic has been gathering dust for the last 20 weeks. I tried to charge everything back up yesterday and no problem with three of the batteries however the forth wont switch on at all or charge, any cunning stunts that can be used to wake it up?

  

  

The battery was fine when it was packed away, I am guessing that it has totally discharged.

  

  

Searched he forum and the best that I could find was to leave it on charge for 24 hours or 'jump start' it with another battery, somehow I don’t think so!

  

Once a LiPo battery has fully discharged then it is un-serviceable.
One of my batteries was replaced after full discharge recently.

This is a good explanation below ...

http://www.instructables.com/id/ ... ithium-Polymer-bat/

Thanks for the feedback Bent, much appreciated.  Great information from the link but will not take a chance and will get a new battery, as he says it will never be 100%

You can jump start a lipo battery so that it takes a regular charge but you need a Dumb charger . I have several lipos back from 2007 that had died and I still use them for setups . I would not use a once dead lipo to fly but they come in handy to use when updating firmware or just setting up cameras etc . You need to get the cell voltage up to at least 3volts each or in this case 9volts total before the regular charger will see it as ok and start charging . I use a wall wart as the dumb charger . You need one that outputs 12v at less than 1Amp . The one I use is 12v at 800ma . You need a volt meter or some indication of the cell voltage to stop it when it gets in that 9-11 volt range then immediately put it on a regular lipo charger .

Zamboon Posted at 2017-6-3 02:35
will not take a chance and will get a new battery

Very wise decision Zamboon.

The risk of using such a battery even if conjured back into life would be immense considering it being an *intelligent* battery and not just your run of the mill lipo which others are referring to.

A better way would be to replace the internal cells with new ones, but it would certainly void your warranty to fly with such a home refurbished pack, and there would have to be a way to reset the pack's memory so that it thought it was new.

I wish there was a way to use cheap, generic LiPo packs. But without the smart circuitry in the packs, you would lose a lot of functions. And while some of it could be integrated into the charger and the drone itself, things like tracking the individual battery's charge/discharge cycles wouldn't be possible.

this sucks reading this, as i haven't used my phantom since last summer. no doubt now all 3 of my batteries for that are all dead. its a phantom 2 vision+ anyway

boostedford Posted at 2017-6-3 21:10
this sucks reading this, as i haven't used my phantom since last summer. no doubt now all 3 of my batteries for that are all dead.  its a phantom 2 vision+ anyway

It is probably good to set an alarm on your phone's calendar to remind you to do a maintenance charge once a month when you aren't actively using it.

boostedford Posted at 2017-6-3 21:10
this sucks reading this, as i haven't used my phantom since last summer. no doubt now all 3 of my batteries for that are all dead.  its a phantom 2 vision+ anyway

Note that it should take years for a battery to discharge from a 65% charge.  Are these batteries discharging that quick?  Sounds like something is wrong.

These DJI Intelligent Flight batteries are different from other similar batteries.
It has a small processor circuitry that runs on its battery to get you battery life indicator and power the battery on/off.
So it drains batteries more than other regular battery packs.

Xman1 Posted at 2017-6-4 08:41
Note that it should take years for a battery to discharge from a 65% charge.  Are these batteries discharging that quick?  Sounds like something is wrong.

i didnt even know at the time that i had to keep the batteries at that %

boostedford Posted at 2017-6-5 12:32
i didnt even know at the time that i had to keep the batteries at that %

They take their most damage between 80 and 100% and again at 0 to 20%.  Anything outside of there and you should have a long life battery.  If you frequently ignore that fact and leave them constantly at 100% and discharge them to 0%, I expect the battery to at least last the warranty period, but if you treat them kindly, you will probably get 3x the life out of them, assuming no defects in manufacture.

They also will not take too kindly to charging while hot.

Note I have mine set to auto discharge at 3 days instead of the default 10.

Note charging to 100% for a flight is not a big deal.  Just don't leave them at 100%.  Use the power within a couple days.

laceyboy Posted at 2017-6-4 11:59
These DJI Intelligent Flight batteries are different from other similar batteries.
It has a small processor circuitry that runs on its battery to get you battery life indicator and power the battery on/off.
So it drains batteries more than other regular battery packs.

Modern microprocessors draw very low amounts of power in sleep. Like 0.005mA (5µA) with the adc off. It's for all practical purposes paracidic and wouldn't drain a battery. Something else was drawing power, or the programmer didn't know about sleep modes and setting an interrupt to wake (very unlikely).

thehippoz Posted at 2017-6-5 13:00
Modern microprocessors draw very low amounts of power in sleep. Like 0.005mA (5µA) with the adc off. It's for all practical purposes paracidic and wouldn't drain a battery. Something else was drawing power, or the programmer didn't know about sleep modes and setting an interrupt to wake (very unlikely).

Unfortunately, those modern processors are unlikely used in those dji battery packs.

laceyboy Posted at 2017-6-5 13:45
Unfortunately, those modern processors are unlikely used in those dji battery packs.

huh?!?

What *modern processors* are you talking about?

The Battery is designed to sleep for long periods of time without draining.

Xman1   "If you frequently ignore that fact and leave them constantly at 100% and discharge them to 0%, I expect the battery to at least last the warranty period  "

Aww man didnt you read the above link i posted?
You cannot fully drain a lipo battery, otherwise throw it in the bin, dont worry about warranty period lol
Also not sure where you got that info about damage in the 1st 20% of LiPo discharge, this is totally false as well.

laceyboy Posted at 2017-6-5 13:45
Unfortunately, those modern processors are unlikely used in those dji battery packs.

Sigh, forget this forum.. Not in the sense your thinking, but pic micros . That's what is running the light display.

I made the mistake of relying on the DJI 3x battery charging hub to keep my batteries at 50% charge while set on sleep mode. Today I switched back over to charge mode after a few month period and only one of the 3 batteries took a charge. The other two must have drained completely and will not charge at all.

So be warned if you use the 3 hub charger set in sleep mode to keep your batteries at 50% keep an eye on it to ensure it's working properly.

Fellow member here with dead mavic batteries. Mine died in storage, i took them apart as they were out of warranty and tried to boost them.

The lipo packs seem fine but the microprocessor inside them will never allow them to output power.

So you can take them apart, use them in a rc car/plane etc. but never in a mavic ever again.

Take it as cheap insurance for your drone, $89 for a new battery isnt bad, I just buy new batteries and sell them after the season is done for 10-20$ less than new with 20-30 charges on them.

I just got out my phantom 4 Pro v2 and the battery was on 2 bars but as soon as I connected it to the charger it started flashing then it dropped to one bar even leaving it on charge for 24 hours it is still on one bar the thing that annoys me is the face I have never flown this quad once so even with zero hours on it it looks like I will have to shell out £169 for a new battery there should be a way of using standard batteries with these quads DJI must make more out of selling batteries than they make from drones when you can buy an equivalent power battery for less than £40 why do we have to buy only DJI items.

Generally speaking with lithium batteries , once below minimum charge level the battery will drop into failsafe battery protect mode, this basically turns battery off to protect the battery...  To activate it , the battery would need to be activated again or have more charge than minimum to restart normal use. They have these activation buttons on iPhone battery test kits been that iPhone also have lithium batteries . Below I have taken a picture of the test board for iPhone batteries that shows the activation button used when a battery falls below charge level  

The only other way to restart a battery Is to direct charge above minimum value