In case it's escaped your notice, the average life of a cell phone is ~a year before upgrading pressures set in. Nearby teenagers here in NZ say " A YEAR- as long as THAT !".
As the Li-ion battery in the obsolete phone is usually good for several years beyond this, it's feasible to use the slim battery pack in space/weight constrained PICAXE projects, & keep the phone handy just to use as the smart Li-ion charger! Although such power house Li-ions typically fetch ~US$20 new, you may thus get one for nothing by putting your hand up at phone discard time.
I'd explored this with a 3.7V 750 mAh "AB043446BE" (the standard battery for many Samsung phones), which weighs just 17g (encased total) & measures ~50mm x 33mm x 4mm. Single AAA NiMH with such a capacity weigh ~12g each & being cylindrical & bulky, pack together poorly.Battery holders for 3 NiMH cells would mean ~40-50g total weight for the same energy.
Before you get TOO excited however, recall NiMH are pretty charge tolerant compared with picky Li-ion, with the likes of even a hacked solar lamp being suitable. However,aside from the phone itself, all manner of DIY smart Li-ion chargers abound of course.
N.B. At "show off time" such a slick Li-ion battery can REALLY enhance overall project presentation. AA/AAAs look pretty cheesy when you've a $$$$ client to impress... Stan
As the Li-ion battery in the obsolete phone is usually good for several years beyond this, it's feasible to use the slim battery pack in space/weight constrained PICAXE projects, & keep the phone handy just to use as the smart Li-ion charger! Although such power house Li-ions typically fetch ~US$20 new, you may thus get one for nothing by putting your hand up at phone discard time.
I'd explored this with a 3.7V 750 mAh "AB043446BE" (the standard battery for many Samsung phones), which weighs just 17g (encased total) & measures ~50mm x 33mm x 4mm. Single AAA NiMH with such a capacity weigh ~12g each & being cylindrical & bulky, pack together poorly.Battery holders for 3 NiMH cells would mean ~40-50g total weight for the same energy.
Before you get TOO excited however, recall NiMH are pretty charge tolerant compared with picky Li-ion, with the likes of even a hacked solar lamp being suitable. However,aside from the phone itself, all manner of DIY smart Li-ion chargers abound of course.
N.B. At "show off time" such a slick Li-ion battery can REALLY enhance overall project presentation. AA/AAAs look pretty cheesy when you've a $$$$ client to impress... Stan
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