Cellphones in Japan > About battery life.

About battery life.

Japan's insane battery life has to do with the density of the network.

HJ

hmm - but in New york city, the cell network must be almost as dense as Japan due to the number of people who need service, yet my battery still only lasts 2 days if I'm lucky.. it would/should be technically easy to throttle down power use if you spend most of your time near base stations.

Also - phones spend 99.9% of their time in *receive* mode rather than transmitting.. power use when receiving a signal is regardless of cell size. The theory would account for lower talk time, but not lower standby time.. it is standby time that sucks.

I do not know if it is still true since I have not kept up with the industry, but about two-three years ago there was an article in a trade journal I use to receive that talked about new cells the Japanese had started producing that had a much higher power density than the current cells.

The downside was that the US consumer battery consortium did not plan on bringing that new technology to the US in the near future, apparently there was an issue with the profit loss they would have to take when people did not buy as many batteries.

This is off the top of my admittedly poor memory, but considering how US big business has a 'making double digit profit over taking care of their people' mentality, I could believe it.

It might be lithium-ion and lithium-ion polymer

»www.ecnmag.com/ecnmag/issues/200···8ss1.asp

they are already producing devices with Li-Poly batteries, which can be shaped to fit tiny devices efficiently.. and Li-Ion are available for some phones in the US as a replacement for NiMH .. given the overwhelming demand for small and light things in japan they would be working much harder on battery types and low voltage circuits.

Actually, its superb battery life has more to do with how DoCoMo works than anything else. A cell phone's greatest drain on battery power is through transmissions. U.S. and European cell phones still use - for the most part - circuit-switched connections, which require the phone to transmit continuously while the conversation is in progress, even though only one person is talking. DoCoMo is completely packet-switched, so the only time the phone is transmitting is when it is sending your voice or data packets to the network. When the other party is talking, your phone is passively receiving their voice packets, which requires far less power.

I'm certain that i-mode phones will have Li-Poly power sources in the future, but for now, all they are using is the same Li-Ion battery that most of us in the U.S. are using right now.
--
I use conjecture and hearsay. Those are kinds of evidence. - Lionel Hutz

reply to justin
Thanks Justin, that sounds like what I read about several years ago from Japan. Kind of sad that the latest article in ECN is written by a Korean instead of a US American. It looks like we are losing our innovative technical edge.