Ibra wrote:
Let it drain and recharge does the job for me, the 10% is just a threshold that seems to work
That is because the smarts are doing there job, which from apple and sumsung is to be expected. None of the cells got to 0%, and none of the cells were overcharged. If the smarts fail you would have a problem. Of course if the smarts fail you probably have a problem anyway… But taking it always down to flat may increase your MTBF.
Though its the charging operation that puts you at most risk, so should be avoided where possible.
Lithium batteries always include some smart circuitry to monitor their use, it’s often this failure that is the problem. Without the smarts they would fall almost immediately.
Yea not sure about the physics of Li or internal battery components but I want to know how to avoid overheating and fire or shutdown on low battery when my tablet is running Skydemon in flight?
Let it drain and recharge does the job for me, the 10% is just a threshold that seems to work (I get a warning on both ipad & sumsung tab and both switch to dim mode)
My Samsung tablet is from 2012 and my Ipad from 2017, both works fine for operational use in flying (not used for something else), however my phone and its battery goes to the bin every two years….
Ibra wrote:
For electronic gadgets never charge them when their battery is higher than 10% should save you overheat problems
gallois wrote:
@Ibra why 10%? I have heard that figure before somewhere.
AFAIK this is bad advice with regard to lithium batteries.
Typically these batteries act a battery under load and they are often monitored as such. i.e. They are a battery when you have a series of lithium cells which are about 3 and bit volts times a number of cells.
They are not charged as battery however, they are typically charged as a series of cells. i.e. the charging circuit is separate, and controlled as such. You do not want any of the cells to reach 0% capacity as this destroys the battery and is also possible failure mode if the controlling circuit fails to detect this. AFAIK also storing the battery at full charge shortens its life, charging to 80% can extend its life if you can be bothered. I do this on my laptop as I have some software for this purpose.
i.e. it not easy to figure out the 0% and the 100% point for a lithium battery and these are both possible points of failure. There are often some smarts built in to deal with these end points but they are not perfect.
Someone who understand this more thoroughly will explain further and point out my errors. 
172driver wrote:
1) No man-made fibers. Yes, cotton also burns, but it doesn’t melt and cling to your skin. Also doesn’t produce static electricity.
2) Long trousers: I sometimes fly in shorts, but the long trousers are more to protect myself from scraping my skin during walkaround. I’m unfortunately pretty good at blundering into sharp edges so that’s really self-protection.
3) Solid shoes: I can’t drive in flip-flops and I don’t really see how I could fly in them, let alone get up on the wing to check the fuel. Equally important is egress and getting away from the airplane in case of an emergency. Ever tried to run in flip flops?
This is what I do – never man made fibers. And, when water flying, I actually __wear____Italic__ my life jacket. For cold water crossings, I’ll wear either my exposure suit, or my dry immersion suit (depending how cold), though in doing so, I sacrifice flammability resistance. For helicopter flying, I wear my helmet.
gallois wrote:
The problem is that (and I think it is a regulation) tablets like ipads must have more than 90% charge before you begin an IFR flight if you are going to use it as your only electronic flight bag. So it is not always possible to let the charge descend to 10% and then recharge ready for the next flight.
I can’t find any reference to a particular charging level in part-NCO. Indeed, the section of part-NCO that deals with EFBs simply says (AMC2 to NCO.GEN.125) Before each flight, the pilot-in-command should perform the following checks to ensure the continued safe operation of the EFB during the flight: … check of the remaining available battery power, if applicable, to ensure the availability of the EFB during the planned flight;
There is a lot being said about EFB in part-CAT, but during a quick browse through, I could’t find any mention of a 90% figure either.
@gallois I think the same for phone/tablets as for laptops, it seems you don’t get battery/screen overheat and you get better battry life of you go this way:
- You have to drain battery completly, charge it completly and go for another cycle
- You are using it heavily and battery is full, don’t plug the charger
- You are not using it and battery is empty, plug the charger
So one gets a better voltage and thermal regulation this way
I think 10% is arbitrary but any figure before the device enters power saving mode or switch off will do, plugging the charger at 80% is not good: battery does act like huge resistance and overheats and one lose 1 charging lifecycle for barely 20% use…
Yes, I heard 90% for serious EFB stuff but it should be ok to re-charge one time for nect flight: I don’t think one can sequence two IFR flights arrival/departure slots bellow 45min unless he is a real pro but then he should get two tablets 
The fire hazard with lithiums is certainly much lower if you avoid charging them. This is partly due to the much smaller temp rise, and partly because it avoids exercising a defective charging circuit. The latter was IIRC implicated in the infamous Samsung battery issue recently.
But one can’t avoid charging if doing a long flight.
Then – many previous discussions – the device gets a lot hotter because the charging circuit is not 100% efficient, and then you get sunlight related shutdowns in all modern tablets (phones seem to be much better in this regard).
10% is really close to zero. I used to design this stuff and it simply isn’t possible to estimate that there is 10% left, with any degree of accuracy. You certainly cannot achieve it with integration (like a fuel totaliser does) and if you work on the battery voltage, the 10% point is right on the knee where it falls off fast. And if you are doing it really properly, the energy left in a battery has to be adjusted for temperature, so your “10%” could vanish in an instant.
If you’re worried about clothing flammability, the fire probably isn’t survivable
I agree. I recall reading a report on a homebuilt/UL crash where the cockpit was in flames and the pilot was overcome by the fire. It doesn’t get much worse than that, and clothing which doesn’t burn won’t help much.
Also, we as pilots need to be comfortable, and in most of the flying season an enclosed GA cockpit is just too hot.
@Ibra why 10%? I have heard that figure before somewhere. I think on some laptops it is recommended not to keep the laptop plugged into the mains but run it on the battery and recharge when it gets to 10% otherwise the battery gets to a state when it will no longer hold charge.
The problem is that (and I think it is a regulation) tablets like ipads must have more than 90% charge before you begin an IFR flight if you are going to use it as your only electronic flight bag. So it is not always possible to let the charge descend to 10% and then recharge ready for the next flight.
If you’re worried about clothing flammability, the fire probably isn’t survivable. That said, avoiding synthetic fibres sounds sensible, although as Graham says this is more of a wardrobe choice. You can’t cover all eventualities (e.g. wearing wool and ditching) and it’s more important to be comfortable.
The time to be thinking about it is now, and not when it’s too late. I keep a blanket and lightweight coat in the boot of the car in the very unlikely event of a breakdown. The blanket is handy for picnics
I once got told off for landing a tailwheel in a gusting crosswind in flip flops. At the time I was very current so it didn’t matter, but now I wouldn’t be so confident.
In day job I have to fly in nomex flying suit with cotton long sleeve t shirt and long johns, boots, leather gloves and helmet. That’s rather right of arc protection and heat stress can be a real issue to manage.
For my other GA flying I just focus on cotton stuff, long trousers and decent footwear. For Aeros or older types it’s flying suit as well.
It is not just fire either, I have good friends who have spent time getting soaked and windswept in wreckage / had to trek across fields after forced landing.
Like most things I think a sensible balance is the way ahead. I do the same on commercial flights as well.
