Yes non power saving.
Yes graphs are public, station 2809. There is three Sky on the one hub at the moment. They will be re homed at Xmas time. The voltage on Sky2 got to very low 1.9v (the supposed cutout point) before I change the batteries. Didn’t seem to lose any data.
Thanks @peter.jeffery.nz,
I entered your figures into a table with dates as they reach each voltage and did some calculations to help me to forecast when to change the batteries. Prior to my first set of alkaline batteries I didnt know how sudden the drop would be at the end. Now knowing the end droop I reckon for time planning purposes it is useful to note the number of days available between 2.4V and 2.0V. Your Sky2 had 20 days where as my Sky (with 6/8 batteries working) had 16 days, which makes sense.
cheers Ian 
If you are trying to find out what may be the best batteries to use I might be able to setup a custom discharge test using my PowerLab8. I would just need to figure out a somewhat reasonable discharge rate where it doesn’t take too long for each test but yet gives a reasonably useful result. Is the cutoff voltage 1.9V? I would need that too. What battery of tests should I try? 
Hi @gizmoev David,
I thought of doing some tests until I found the graphs on the Energiser web site and now that we have people using different types of batteries I guess the best test is the real test because it is the actual duty cycle in actual temperatures.
The purpose of my examinations is to help to plan for when they must be replaced, or to discover if a pair of cells within the group is not working.
I feel happy with the economics and reliability of Alkaline for my situation. I will not be using power saving mode because wind detail is important to me.
cheers Ian
Update. Managed to get 1.3 years from one charge of Eneloop Pro in my Air. Gave up at 2.5v, would have gone longer if took it down to the Airs 2.4V min.
This sounds quite good.
You used them indoor or outdoor ?
What temperature range have them seen ?
Now I
Its getting winter at your side, right ?
The Air was outdoors.
Temperatures are not extreme here (10-28C daytime averages). A few frosts in winter.
Yes coming into winter now but still mild, being surrounded by ocean helps.
I have used Energiser Alkaline batteries in my two Skys with several layers of aluminium foil folded between the two sets of four cells. Testing if the contacts lack enough tension and to parallel the two sets of 4 cells, rather than the usual paralleling of four pairs of cells in series. One Sky lasted 141 days and failed at 1.83V. The cells had four cells at 1.25V and the other four cells had 2 at 0.5V (NW and SW adjacent + terminal) and 1 at 1.54V(South East corner nearest catch) and 1 at 1.35V (NE corner nearest hinge). The other Sky lasted 154 days and failed at 1.97V and all 8 cells measured 1.0V. Previously using Energiser Alkaline cells without foil my Sky lasted 186 days and failed at 1.86V. My conclusion is that using foil to increase the contact pressure and to parallel the cells made no improvement.
cheers Ian
What is the SKY Battery Drop Out Voltage?
I’m down to 2.86V, Anker Alkaline, probably not the best choice for winter (although we have been unusually warm this year), but I had a pack and they have a good reputation for not leaking (they were on sale too): https://www.amazon.com/gp/product/B07RHX78P8/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
(I have Lithiums in the AIR unit)
How low can the SKY voltage go while still maintaining proper operation?
SKY’s sensors will remain powered down to 2.0 volts, replace threshold is around 2.2 volts.
AIR’s lightning sensor will quit at it’s replace threshold, about 2.4 volts, but other sensors will remain powered down to 1.9 volts.
Discharge curves for alkalines and lithiums are different. Lithiums will maintain a higher voltage for a longer period of time and then voltage rapidly drops off a ‘cliff’.
Hi @Emtonsti Joe,
I have always used Alkaline batteries but I live where it never goes below 5 deg C. Cold is a killer of Alkaline. I describe several results in the above discussion, and this post might be useful to you:
cheers Ian 
A post was merged into an existing topic: Recharge restart for sky after freezing temps : solar panel (SPA)
Hi @edtimm,
I was watching the answers to your question regarding the power requirements for the Sky and decided to test it for you:
My analysis of mAh required is based on the life of a set of Energiser Alkaline cells. They lasted 186 days and stopped working at 1.86V.
Reading the specs here: https://data.energizer.com/pdfs/e91.pdf
Extrapolating from the ‘Milliamp-Hours Capacity’ chart I am guestimating 3000mAh per cell. (much less than 25mA discharge rate AND down to 0.93V compared to the charts 0.8V.)
4 cells are in parallel so 4x3000mAh= 12000mAh at nominal 1.5V.
OR at nominal 3V requires the second set of (4 cells in parallel) but in series and still 12000mAh total at nominal 3V.
186 days = 4464 hours.
12000mAh/4464hours = 2.7mA
And now to view the actual mA on a moving coil meter I attached insulated foil between the battery connection and observed the meter here:
https://youtu.be/l0CMyUJJZho
It is just an unedited video of my test to save others repeating the test.
cheers Ian
Nice experimental setup 
Maybe you missed some short paeaks due to the damping of the analog needle. I suppose the effect will be small.
@iladyman…that’s some good work, thanks!
You saved me the trouble of building a usb cable with a ammeter tap.
The temperatures here have been ranging from 25 to 36 F.
Here is how she rolls…
The way you tapped in with the foil and plastic is brilliant! Thank you for making the current measurement.
Here’s an example of the cliff - these are my original recommended batteries from August 2018 that seem to finally have died on me in a Sky that is fortunately mounted down low…
Note the Air voltage is still looking great even after 21 months…
