My employer, at mission control in Aberdeen, has for a while been using both devices for its field staff utilisation for the photographing and reporting of drilling rig material condition. After a couple of years they have decided to ditch the Samsung variant in favour of the iPhone as the Samsung model has proven to be unreliable and fragile (their words not mine). I knew this to be the case long ago.
Hmm. The performance of my iphone 5 has dramtically decreased in the last few weeks in the battery life. Its really dropped off. I'm now considering the new samsung 5s is it? Smart looking phones, my only problem is the lack of facetime which is the only system onboard that works and for some reason the wife like to look at my face when we're chatting!!
Funny you should mention about the iphone battery being poor, I'm always seeing people plugging their iphones into the mains power at airports.
The issue is the same with all lithium batteries, a lot of people probably have a use pattern that takes the battery from full to nearly empty like 5% or less, then charge to full again, lithium batteries don't like that it reduces the total number of cycles before failure and brings forward the day where full charge is a fraction of the design capacity. The next usage pattern is also bad, people who charge their phone at every opportunity and never let it drop more than a few percent, that will also ruin a battery. The best option apparently is to drain the battery to about 40% and then fully charge again, this apparently allows a higher full cycle count. Occasional full drain is fine but constantly draining the battery is not, regular charging when you get to about 40% to 50% and occasional full drain is a better pattern.
I thought the best way to charge lithium batteries was to keep the charge between 20%-80%. Recharge at 20% and then charge to 80%. I remember one laptop I owned had an option in the BIOS to limit the charge to 80%. On Android phones you are not notified of a low battery until it drops to 14%. On Chromebooks, the warning often pops up when only around 5% charge is left. With lead acid batteries I think it is best to keep them fully charged all the time.
I'm quoting from this bit of work, it might not be accurate? http://www.rm.com/Support/TechnicalArticle.asp?cref=TEC2584306 but personally I thought it made sense, from personal experience of a lot of lithium powered devices over the years. I could be misinterpreting as well, 40% is recommended for long term storage maybe not for bottom end discharge?
Charging strategies obviously matter more when the device has a difficult to replace battery, my Lumia 820 could live forever fairly easily with its replaceable battery but my Lumia 1020 requires surgery to replace its battery.
Especially if they are flying to the US of A, where the authorities have found yet another reason to persecute flyers by insisting that phones must be charged due to the latest "terror threat". To be honest I would feel more secure traveling on a flight full of "potential terrorists" if all phones were fully discharged, or the batteries removed. Might help for the landing at Manila as well, where the sound of phone starting up fills the cabin, even before the first bounce of the wheels on tarmac.
I always leave my devices to charge overnight. It may not be the most efficient for the battery but its the easiest option for me. I have never had to replace an Apple battery.
The article made no reference to testing with depth of discharge >50% and < 100% so nothing can be concluded for a depth of discharge of 80% from that article. The article does suggest that keeping at battery at 40% charge for storage is much better than 100%. I think I will now modify the charging of emergency-only phones accordingly, as I was charging them each month to 100%!!
I am deeply interested in this subject, total discharge is supposed to totally screw a lithium battery however I just recently bought a 9 cell original lithium battery for a Lenovo X220, extended life runs for about 8 hours on my X220, the thing was second hand new unopened from eBay, when I received it the thing was empty, absolutely empty, sealed box, lenovo tape everything right but totally empty. I thought, what have I wasted my cash on, this was a 40 quid battery, new they are about 80 to 100 or more but for a second hand laptop that is too much to pay. Anyway I charged it and checked the metrics and sure enough it was manufactured late 2011 was three years old had never been charged and took its full design capacity on first charge, 94 somthings (I'm in the pub fairly sure VA hours or the likes pished) So far fully met my expectations and the drain on it is fine in the real world, but I given that it was empty for 3 years and first charged by me about 2 weeks ago I am still scared about its longevity
One of my sister companies, that we worked closely with, just a few years ago, used lithium batteries to power their downhole survey tools. And no doubt still do. Massive business in the oil industry. Virtually every well drilled uses them downhole. They were a good couple of feet long and about an inch in to an inch in diameter ( to fit inside a cylindrical housing ). And they used several at a time. They ran them to expiry if necessary and reused them once recharged. They basically used and "abused" them. No consideration was given to discharge levels before recharge or the like. These are typical but look a bit longer. Racked for storage.
