Keeping Cell Phone On

I am in urgent need of finding a way to power a cellular telephone ( in this case a Motorola / Nextel i58sr ) for an extremely long time without recharging. I will be operating in an environment with NO ELECTRICAL ACCOMODATIONS. Presently, I get approx. 2 days of life out of the normal extended life battery sold with the telephone. I am looking to get 10 or more day’s life. I have considered attempting to arrange the batteries is parallel in hopes of accomplishing my goal, however, I am not sure if this is possible with a 3.6v lithium ion battery. I would like to make it known that the size of the phone unit along with the battery or batteries is not an issue. ie. if I must house all the batteries and the phone in another component such as a plastic box, this would still accomplish my goal. Furthermore, I will be unable to turn the phone on if it looses power, so the battery output must remain constant. Any help or referrals you might give me would be greatly appreciated. Thank you for your time. P.S. simply charging several batteries and replacing a depleated batter with a charged one will not accomplish my goal. The telephone unit MUST remain ON. Therefore the power supply must be continuous.
- Paul (age 33)
University of Michigan, Ann Arbor, MI

Your phone must come with an external charging port. The external charger provides some level of dc voltage. You could measure that, then rig up an external battery supply to supply the same voltage. There may be some tricks, such as the way the charger voltage depends on the voltage of the internal battery, but you could try this simple fix for starters. By the way, we don’t really know anything about your cell phone, so we can’t guarantee that it won’t get fried. You read it here- so you can’t sue us successfully if this doesn’t work.

Mike W.

(published on 10/22/2007)