Hi all,
I’ve moved house and I don’t have any power sockets near my smart meter.
If I buy a emonTx and connect only the optical pulse count sensor will this work in low power mode via the battey, roughly speaking how long will the 3 x AA batteries last if the emonTx is just counting pulses, nothing else will be connected to the emonTx it will just send it’s data back to the emonpi.
I like the pulse count it’s very accurate and can be used to tweek the calibration on the CT sensors, worked like a charm in the old house…
I would suggest and strongly recommend using an emonTH instead.
The emonTH software is highly optimised for battery operation, and (especially if you disable the humidity & temperature sensors) should give a much greater life than you could expect from an emonTx - unless of course you ported all those optimisations into the emonTx.
For the emonTH, battery life of course depends on the type (and brand) of battery, I think you are talking in the order of 6 months to a year with a good high capacity, low self discharge, battery.
That’s the ‘best’ use of the pulse count, because deriving power from it is problematical - a c.t. is always better for that. Bear in mind of course the pulse has a serious limitation if you export energy - it doesn’t work when exporting because the meter LED can’t do a negative flash. 
( 
- If the LED went from flashing on when importing, to flashing off when exporting, and the on and off periods never came close to being equal, then it would be possible in software by finding the light/dark ratio to determine the direction of energy flow. But I know of no meter that does that, most put the LED on continuously when exporting.)
Thanks Robert had no idea that the emonTH would work with the optical sensor but looking at the shop it looks very simple, order has been placed.
Not got any solar in the new place yet will add it in a couple of years once the warrety on the roof has ran out.
It arrived and was very straightforward to set up, getting a rssi of -64 is that ok?
That’s more than good enough. When it gets down to -80 or so, you should expect to start losing it on occasions, 16dB above that gives you plenty of leeway.