I undestand that the relay contacts need to stand 1Amp, small
pcb Aromat relays can stand up to 5Amps.

It is better to use a capacitor at the processor side, instead
of the relay side, so the relay can drop the battery voltage as
low as zero during the current peak and the processor stays
working nice, as well it will serve as a nice filter.
But this will never happens using a latching relay...
5mA 100ms...

I am producing a similar device. It works one second every
5 minutes, no electrical power at the site, so, there is a
power off circuit that just "cuts" all power except for a
RTC with alarm. The alarm powers it up again in 299 seconds.
A small solar cell recharges the 3xAA NiH bat with 150uA...

Wagner.



Mike Harrison wrote:
> You'll need a big cap to supply the pulse to the relay (as you won't
> want to cause a brown-out on the battery supply when it fires), watch
> the leakage spec on this. Do you really need a whole  amp for the
> relay? That's a pretty big relay. Have you considered a solid-state
> output, or a latching relay ?