DJI,

Can any Engineers confirm
1.  How long the TB47 can be left at 0% or under 5% before they are recharged.
2.  If placing in long term storage how long can they be stored safely once they have been charge to 50%

following the thread

Why do you need an engineer to tell you?

In answer to your questions......

Exactly the same as any other packs that share Lithium Polymer chemistry!
1. Not very long unless you want to destroy them
2. Pretty much indefinitely (in the right conditions) but some loss will occur naturally over time with as little as 2% per year (stored correctly) and up to 10-12% over 12 months if stored in a warm environment.

markjacobs.talk Posted at 2015-6-29 03:14
Why do you need an engineer to tell you?

In answer to your questions......

Mark,

Your reply seems to have two answers, so a little confused.  

Not Very Long ....   Is this days/ weeks / Months ?

Pretty Much Indefinitely  ?

Why An Engineer Mark?  

Well there are many members on the forum with different levels of experience and just thought that DJI could give a formal response,  so we know what the manufacturers recommendations and position is in respect to how long we can leave our batteries uncharged, after a flight for example.  So would it be safe to leave uncharged after a flight for say a week or two weeks or should we be re-cahrging immediately after flight knowing that the batteries may need topping up if not flying soon after re-charge.

I just see this as re-charging too soon.  If you wait for perhaps 5 days for your next flight the batteries will need charging again or certainly topping up.  I know it is ok to top up as it states that in the DJI Manual but surely this just adds another recharge to the total of recharge cycles that the battery is allowed.  I am also unsure if the battery chip is programmed to simply stop charging after so many cycles, in which case we don't want to re-charge too many times if we can leave the battery for some days or a week before re-charging.

Hope I have explained my question and concerns properly ...

GB44 Posted at 2015-6-29 03:35
Mark,

Your reply seems to have two answers, so a little confused.  

Your post had 2 questions ... : )

1 ... recharge them as soon as possible if you discharge them as low as you said.
As I understand it, If they drop below a certain voltage they wont "boot" again.  
If you can´t recharge them right away ... don´t do the deep discharge ... Leaving them at 15% would probably give you a bigger margin before they drop to low.

2 ... store them in the right temperature at 50% and they will last for a long long time.
I can live with 2% / year ... thats 1% during winter when I wont be flying as much ...

GB44 Posted at 2015-6-29 03:35
Mark,

Your reply seems to have two answers, so a little confused.  

But your original post had two questions - Hence my two answers

OK - In answer to question 1. It is NEVER a good idea to leave a Lithium Polymer chemistry pack in a state of discharge for anything really longer than a day or two. Personally, once I've flown and if I'm not going to be flying the next day I allow the pack to cool back down to ambient and then charge it to 50% where it sits until I am ready to use it again. I then grab it, charge it to 100% use it and repeat
With respect to question 2. a lipo properly stored (at around 3.85v per cell and in a cool environment) can be stored indefinitely but, like all lithium polymer chemistry based packs will lose some capacity over time (numbers quoted in my thread above). Unfortunately this is just a characteristic of the chemistry and nothing can be done about it.
I hope that clarifies matters.
   

markjacobs.talk Posted at 2015-6-29 05:24
But your original post had two questions - Hence my two answers

OK - In answer to question 1.  ...

Cheers Mark,

Appreciate you explaining it in simple terms.