On Mon, Feb 14, 2011 at 2:09 PM, Tony Firshman <t...@firshman.co.uk> wrote:
> > > On 14 Feb 2011, at 20:01, Plastic <plasticu...@gmail.com> wrote: > <snip> > >>>> > >>>> Is the CR2032 man enough though? > >>>> > >>> > >>> > >>> The CR2032 is 3V 235ma, and on this card would need to be replaced > every > >>> three years or so, which would be a simple "pop a new one in" > operation... > >>> The 40LF220 had a lower current capacity but was designed for a long > >>> shelf > >>> life of ten years, hence the bulk. So yes, the CR2032 truly fits this > >>> application. > >>> > >>> The format is standard for battery backed clocks on PCs, but was quite > new > >>> in the late 80s. > >>> > >>> I will look at current costs for getting a batch of 100 of these tiny, > >>> single layer PCBs made. > >>> > >>> Couldn't the card have a battery socket so that only the battery need > be > >> replaced? > >> > >> ( ... and why are you not yet living Texas time - it is 2am (8-)# ) > > > > > > That is exactly what I was describing ;) A simple adaptor card to a > CR2032 > > socket, and a CR2032 battery. > Ah sorry. > 3 years though seems a mite short. I wonder if there is a more beefier > battery that is thin enough - or maybe a chargeable one? > There is, but it has 50% higher capacity and costs $12 instead of $0.99 at the supermarket. I said three years as a minimum. It's quite possible that it would last 5-6-7 years - I'm just being very conservative. Also, the CR2032socket in bulk is under $1, but the socket for the CR2045 is $7.80 in bulk. I think people will happily pay $15-20 for a 3-5 year battery change at 99p than pay $25-$30 for an extra couple of years. Also, changing the CR2032 batteries is so easy... 15 seconds, including removing and re-inserting the card. Dave _______________________________________________ QL-Users Mailing List http://www.q-v-d.demon.co.uk/smsqe.htm
