Chris: One of the more interesting batteries is the one located within a Polaroid film cartridge. The battery is a flat sheet, about the size of a finished photo. The battery has two foil film terminals on one face. If you carefully rip the thin film holder apart (very sharp edges), you can salvage the battery.
After shooting the (8 or 10?) photos, the battery still has quite a bit of power left. This isn't a rechargeable battery, but it certainly has a low source impedance. This battery may have the highest short-term power to weight ratio of any commercial battery. Be very careful if you try to section the battery using a knife or scissors! Ed Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military & Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Thursday, November 23, 2000 3:47 PM To: [email protected]; [email protected] Subject: Re: Rechargeable Batteries Hi Mark. You asked: << why do so many battery operated equipments state that they must not be operated using rechargeable batteries? >> There is no one all-purpose reason, but the two main ones, at least the ones I worry about with battery powered stuff, are: 1. As you already implied, terminal voltage. NiCads are typically 20% lower terminal volts than Alkaline cells, and as lots of battery operated stuff needs a stabilised supply the headroom required to produce a stabilised supply can take the volts down too low. 2. Short circuit current is very high with NiCad's. If there is a fault internally, or as in one case that I had, if you drop it in water, the resulting current can destroy the PCB and associated components. Alkaline cells, ar even better, Zinc/carbon cells have a much lower short circuit cirrent and the liklihood of damage, or even fire, is reduced or even prevented completely. The short circuit thing is interesting. My son has a radio controlled car with a 7.2V NiCad battery pack. The short circuit current was enough to melt the PVC insulation on the battery wires, 1.5mm^2, and I measured it subsequently at 82Amps. You could probably start a European car with one of those! Chris Dupres Surrey UK. p.s. Anyone wrapped up a alkaline watch battery in aluminum foil? Don't! ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
