Smartphone battery capacities - a critical issue
Published by Steve Litchfield at 13:59 GMT, February 12th 2008
Why does smartphone battery life have to keep getting worse and worse? And can I prove this underlying trend?
A few weeks ago, I proposed that there was a battery threshold,
beneath which one was miserable and above which one was happy. I even
went as far as to name models that were above and below this virtual
line. We've now had the announcement of (for example) the Nokia N96,
with a 950mAh battery. How will this fare and how does it compare to
devices of today and yesteryear?
As usual with these pretty charts, there's only room for a handful of thumbnails, but I still hope to make a point. Right at the top, we see the past - glorious battery life (weeks) but at the expense of lacklustre screens, dependence on replaceable AA or AAA cells and little or no wireless/phone functionality. Although it would be cool to speculate on the life of (say) a modern Nokia Nseries device powered by two AAA cells totalling 3000mAh between them, i.e. three times the current capacity of many internal rechargeable Li-Ion cells, it would be fairly pointless since the market seems to have categorically turned away from disposable batteries towards internal rechargeables, for both lower impact on the environment and also greater convenience. The days of AA and AAA-powered handhelds are long gone, I suspect.
So, turning to the modern era, note the dark red line above, representing an approximation of where devices need to lie in order to stay on or above my aforementioned 'threshold' and to keep their owners happy. The line rises because, obviously, the less functionality a portable device has, the lower its power needs and the less it will be used, meaning that the manufacturer can get away with a smaller capacity battery.
At the high end, with goodies like high megapixel still and video cameras, Wi-Fi, GPS, DVB-H receivers and so on, the extra power drain is significant, plus there's the on-more-often factor, as users naturally start using the features they've paid for. If anything, the dark red line should curve up slightly, but I've been generous and have kept it straight. The orange line reflects roughly the current trend, showing that battery life is becoming more and more an issue with today's 'do it all' smartphones.
As wonderful as many of Nokia's Nseries are, for example, and even allowing for software and hardware optimisations in recent chipsets and firmwares, you can't (to quote Star Trek) change the laws of physics - energy is energy and when it's all gone then it's all gone. It takes a finite amount of current to power a 2.8" colour screen with backlight, it takes a finite current to power up a camera or GPS or Wi-Fi radio, etc. and at the end of the day I'd much rather have a definite larger battery with oomph in hand than a set of optimisations that make only a slight difference.
In terms of modern Symbian OS devices, the Nokia Eseries communicators are close to the red line and are generally amply equipped for their purpose. The Sony Ericsson UIQ 3 smartphones, not shown above but lying somewhere close to the HTC Tilt pictured, are slightly underpowered but usably so. The culprits here, as noted by many a commentator over the last few years, are Nokia's Nseries 'multimedia computers'.
Now, don't get me wrong, I love my N93 and N95 'classic' to bits and find them incredibly useful. But when using either of them as my main smartphone, battery (1100mAh and 950mAh respectively) was always an issue and I'd be in trouble trying to get through a single day of use and became used to carrying around a Proporta charger in a spare pocket. The release of the N95 8GB (with 1200mAh battery) helped somewhat and solved the matter of getting through the day, albeit often without much to spare.
But, with this week's launch of the N96, with 950mAh battery, and even the release of the N82, with 1050mAh battery, I have to observe that Nokia's Nseries team really hasn't learned their lesson here - both devices struggle when used to their potential, for want of a larger battery. The Eseries designs approach build materials and battery life from a 'never mind the weight, check out durability and battery capacity' standpoint and this resonates with me. Whether my smartphone weighs 110g or 130g is pretty irrelevant, surely, compared to the average person's body weight and arm strength, yet those extra 20g could allow the inclusion of a battery with 50% more capacity.
In my opinion that's a tradeoff well worth going for. Smartphone designers everywhere - try and keep your creations on the red line, please!
Steve Litchfield, All About Symbian, 13 Feb 2008
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Categories: Comment, Hardware
Platforms: General, S60 3rd Edition
Feature Discussion
stuclark
Nokia's excuse for the BL5C in the N96 is sizing. Sizing of the handset that is... Apparently fitting a bigger battery would have made the phone too large.
However, Steve's point is valid - there are very few smartphones available which actually provide a reliable 24+ hour service without being recharged. My two current phones, a Nokia N95-1 and a Motorola Z8 both have great trouble lasting 24 hours, especially when their HSDPA data abilities are used to the full and set to retrieve email on a push or timed basis. Add a little commuting and subsequent cell re-registering into that equation, and sometimes you're lucky to get 8 hours out of the phones.
Luckily the Z8 supports USB charging, so I can give it a quick boost from my laptop if on a train, but the N95 doesn't have this feature. If you've ever tried using a N95 as either a USB or Bluetooth modem, you'll know that a full battery lasts about 2 hours before expiring, whereas the Z8 will keep going as long as the laptop it's connected to is turned on. (a 3 hour battery on my laptop is able to keep the Z8 fully charged while being an active modem, and run the laptop, for about 2 hours)
bartmanekul
I keep wondering what people would have prefferred - the N96 spec as it is, or no 16GB memory and a bigger battery?
Or perhaps no TV tuner, and a bigger battery?
stuclark
I think people would have lived without the TV tuner... 16GB NAND flash RAM doesn't take up that much space... the N95 8GB managed to get some in PLUS a bigger battery than the BL5C.
bartmanekul
True. But in taking away the tuner, what sets it apart from the N95? Very little really.
Unregistered
n81 looks pretty bad on that graph. I though so initially too. I was getting less than a day out of it. Couldn't rely on the alarm to wake me up in the morning without plugging in the charger. However, I found that the battery seems to last much longer if you turn off the annoying flashing light under the navi key.
fchin
When you have cells in series, it is incorrect to sum up their capacities (i.e. in mAh) to give a total figure for the battery - i.e. 4x 900 mAh cells in series do not equal 3600 mAh in capacity - but 900 mAh. Thus the diagram showing the devices taking individual cells (which almost always have them in series to provide sufficient voltage) overstates their capacity somewhat!
The statement that "...two AAA cells totalling 3000mAh between them..." is presumably based on the incorrect assumption that you can sum the capacities of cells in series - I haven't seen an AAA cell with a capacity greater than ~1000 mAh yet!
Umberto
Comparing the performances of a PSION or a PALM M100 with a Nokia N95 is something like the comparison between a 1000 cc car with a Ferrari (Porsche or so on). Anyway, why do not use an external battery pack with rechargeable AA batteries (as example 4 batteries of 2500 mA/h capacity) if you really need more power?
Bosambo
"Luckily the Z8 supports USB charging, so I can give it a quick boost from my laptop if on a train, but the N95 doesn't have this feature"
There is a USB charger for the N95 (and any other phone using the new tiny adapter plug) I believe it's the CA-100. I bought one from ebay only to find it was not genuine...so I can't really tell you how good it works. Ebay complains department here I come.
I'm reading a story on Gizmodo about phones with in built projectors. I wonder when these tech sites get people all worked up over super duper features if they ever stop to consider mundaneties like battery life, basic features like cut and paste *cough*iPhone*cough* and other feasabilty before getting all destracted by the pretty lights and colours?
slitchfield
fchin: I'm sure you have an amount of technical expertise, but I'm no dunce either, having a degree in Physics. And, I'm sorry, but to take your line of argument, you could have 100 AA cells, each rated at 900mAh - are you still saying the usable output wouldn't change from the same 900 figure??
Oh, I see, you mean the mAh figure would stay the same, but the VOLTAGE would change, effectively? So greater power output overall? OK, that makes sense now.
mAh is an established indicator of battery capacity though, and yes, I know it's not exact and that there are a zillion other factors, like how fast you actually draw on the charge, temperature, etc. but to me it's still a good guide that has proved its worth in the real world. So I apologise for the inclusion of the Palm and Psion in my chart, it seems that their rating should be half what it's shown to be. 8-) Just ignore them and concentrate on the lower units, which work at more or less the same voltage!
stuclark
Quote:
Originally Posted by Bosambo
"Luckily the Z8 supports USB charging, so I can give it a quick boost from my laptop if on a train, but the N95 doesn't have this feature"
There is a USB charger for the N95 (and any other fhone using the new tiny adapter plug) I believe it's the CA-100.
|
I meant
natively supports USB charging
Unregistered
Nice graph and demonstration. that is exactly why i find my E61 a googd fit : features, keyboard and correct autonomy.
but as an electronic graduate, i have to state that two AAA batteries of maximum 1.5V/1000mAh equates an available power delivery of 3V*1000mAh so 3000mWh, which is basicly the same of a 3,6V average (4.2V on top, 3V at the end) 800mAh in terms of what energy is available.
On my regretted psion 5MX, 2 AA rechargeable batteries of max 1,5V/27000mAh where yet more usefull.
i am testing the bookeen
http://www.bookeen.com/ebook/ebook-reading-device.aspx it has a small battery but auto recharge it self at eveyr usb plug, eink screen with very low consumption, but really lacks of function so as being hardly usuable. Still it would be an interesting point on your graph.
As a power user of such electronic devices, i have invested in brando small lithium-ion batteries with a USB connector. 5V/2000mAh available with 1A current capability allowing charge or function of quite a few portable device, including my bike front lamp :-)
Bosambo
Quote:
Originally Posted by stuclark
I meant natively supports USB charging
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By natively I assume you mean using the same cable as the Motorola?
stuclark
Quote:
Originally Posted by Bosambo
By natively I assume you mean using the same cable as the Motorola?
|
The Z8 will charge with
just a USB cable plugged into a laptop. The N95 (and all other Nokias currently) will not. They need an extra cable plugged into their power socket.
Bosambo
Quote:
Originally Posted by stuclark
The Z8 will charge with just a USB cable plugged into a laptop. The N95 (and all other Nokias currently) will not. They need an extra cable plugged into their power socket.
|
Thats what I mean. The CA-100 JUST plugs into the USB port and then into the phone...no extra attachments or drivers or software needed.
malerocks
Great article steve. Agree with it throughly. Am using an n93 currently and am able to pull a day through with the 1100 mah battery. But i have to keep unnecessary stuff off when not using it. Eg. Automatic wifi scanning to off, data connection to when needed, push email to retrival every hour instead of more frequently, etc.
Unregistered
When I saw the picture for the article, I thought you were going to announce that Duracell were going to bring out mobile batteries. They'd be really good IMO.
Unregistered
What really gets to me why Nokia and many other manufacturers don't just realease a 1.5x to 2x sized battery for their handsets? This will solve the problems people have with battery threshold. If you don't like a slightly thicker handset then use the standard battery. At least give us the option to choose! This is unlikely to happen because it would hurt their sales. They don't want you to have the perfect handset so you'll come back for more.
IMHO manufacturers can fit a higher capacity battery into about the same space if they wanted to. Who remembers those Lithium Polymer batteries in Nokia 6310? The battery is built into one unit which acts as a battery cover and encases the battery thus saving space, instead of having both battery which is encased and a separate battery cover. There is also space wasted because the battery cover is never "tight" against the battery. There is about a mm gap for smooth sliding on/off cover. For example the BL-6F 1200mAh battery can fit into the n95-1 but the cover leaves about a mm gap all the way round. A slightly raised cover and the battery will fit perfectly. Will Nokia do this? Obviously not...
It maybe possible get larger sized batteries from 3rd parties but they are usually of poor standard and don't pack as much capacity into the same space.
Rant over.
sturgeon
I know this has been mentioned before, but this is what we need. It says
"Given the mature infrastructure behind silicon, this new technology can be pushed to real life quickly," I wonder how quickly? Yesterday would be good!
http://news-service.stanford.edu/new...re-010908.html
s.
bills2north
Finland canīt make batteries like in the old days.
Evironmental codes are more strict now. Where does your battery come from?
China? Hungary?
No doubt Nokia could make a stronger battery, and itīs just one more serious reason why I got the E90. Its 1500 battery may not last days like they say.. but itīs The Biggest phone battery Nokia makes ;-)
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