For a given size (and circuit board footprint) a supercap will have much less capacity and it has an exponential voltage decay curve, so it might have plenty of charge but not at a voltage that will hold the data.  This usually means hours, not days of backup.

A good rechargeable lithium will last several years, maybe longer as there will be no charge/discharge, maintains voltage until it is nearly exhausted, and can hold the data for days or weeks.

On Wed, May 9, 2012 at 12:55 PM, Dave Taht <dave.taht@gmail.com> wrote:
On Wed, May 9, 2012 at 9:47 AM, Eric S. Raymond <esr@thyrsus.com> wrote:
> Dave Taht <dave.taht@gmail.com>:
>> What would be the change in cost and delay in manufacturing to switch to
>> using a supercap, rather than battery?
>
> Why would a supercap be better?

Effective lifetime of... forever. no need for replacement. insanely
fast recharge. smaller (probably). What's not to like?

I am not in a huge hurry to get into manufacturing, and I merely
wanted to cost out what what it would do to the bom, any changes to
the PCB, and get an estimate for the time it would take to do. I think
it will bump the unit cost up slightly,
but what price, forever?

> --
>                <a href="http://www.catb.org/~esr/">Eric S. Raymond</a>



--
Dave Täht
SKYPE: davetaht
US Tel: 1-239-829-5608
http://www.bufferbloat.net
_______________________________________________
Thumbgps-devel mailing list
Thumbgps-devel@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/thumbgps-devel