AIR battery life mystery

Hi there

I have one of the early AIR’s that has been in the field since about Sept 2017. At the the time, I installed the recommended Ultimate Lithium batteries.

The 1st set of lithiums lasted over a year … in fact I replaced them around November 2018 even though the original batteries were still behaving just fine.

The 2nd set of lithium’s lasted about 4-5 months and the AIR went offline suddenly in March 2019.

Today (July 2019) I observed that the 3rd set of lithiums are in decline … battery voltage is reported to be about 2.7V. I have feeling that the AIR will fail again sometime soon.

I have some theories …

  1. only the 1st set of lithium batteries were good, the others are all faulty or had exceeded their shelf life ?
  2. my AIR has had a firmware update that causes it to consume more energy ?
  3. my AIR has developed hardware fault ?
  4. perhaps I’ve moved the hub, and the AIR’s signal to the hub is now weak causing it to burn more energy trying to transmit to it. (wild guess, no evidence)

P.S. I also have a SKY deployed here and its batteries seem just fine, making my 1) above seem unlikely.

Does anybody at WF have any advice about this


You can also eliminate #2. 1 and 3 are the most likely.

I would rule out the shelf life part of #1, since they have an insanely long shelf life that even the first day of production should still be well under.

I have yet to change batteries in any of my three Air units, and one of them pre-dates yours by 6 months. (AR-00004424 is down to 2.50V as of this morning for those keeping score at home.)

Hardware issue or counterfeit bunny batteries would be my guesses…

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  1. An option is that the hinged door on the battery compartment is not pressing tightly against all of the cells OR the spring pressure of the contacts is not pressing hard enough to ensure a zero resistance contact with all of the cells. Measuring the voltage of each cell when you remove them will help to determine if this is the cause. And I mark the cells to know which cell is in each position relative to the hinged door. I suspect this issue with some of the results of battery voltages after being removed from the Skys. And to prevent this problem in my 2 Skys I use several layers of folded aluminium foil to create more pressure between the cells and the contacts. Another improvement is to rub the contacts with an erasure to clean the contacts when replacing cells.
    cheers Ian :slight_smile:

Interesting info, thanks to everyone.

I’ve surveyed some other AIRs that are publishing their battery voltage and I now suspect a hardware fault in mine. At least 5 other AIRs that’s I looked at are reporting > 3 V and that voltage is typically very stable over many months.

@ladyman’s idea to look at the contact pressure of the battery compartment is interesting and makes sense and I’ll definitely take a look at that.

I guess it’s possible that I got a bunch of bad batteries but I buy Ultimate Lithium’s from the same source, Amazon, as I always have.

Amazon is full of gray-market and pirated merchandise (both directly from them and from third parties in their marketplace), and a quick search of Google will reveal an interesting story about how Amazon went out to third parties trying to buy “official” merchandise when the manufacturer wouldn’t sell directly to them…

I would eliminate 1 and 2, as these lithium batteries have a very long shelf life and we are all running pretty much the same firmware. My AIR is still running with the original set of batteries and is currently showing 3.5 volts.

I purchased a SPA and plan on wiring it to the AIR.

Ok, I can imagine that Amazon might do exactly that :slight_smile: But, the product I ordered (Everyready Ultimate Lithium) appeared to be in correct, original packaging. Hmm Ok, maybe I’m being too naive.

So, where should I buy Ultimate Lithium’s if not from Amazon ?

In Australia the cheapest place that I have found to buy Ultimate Lithium batteries is Bunnings hardware. $10aud for 4. They have a policy that if any product is found advertised cheaper they will beat it by 10% so they tend to always match or beat the price. The supermarkets are dearer. I have confidence that they would be genuine.
cheers Ian :slight_smile:

I had the problem of short battery life from the start with my AIR. I was beginning to buck at spending $20 every few weeks for new batteries. But WeatherFlow kindly replaced the unit and I’ve had no problem since.


Well, my AIR is now down to 2.3V putting it officially in the “replace battery” territory. It’ll fail today or tomorrow.

I’m kinda ruling out the batteries themselves as the source of the problem. My SKY’s batteries come from the same source and its doing fine.

Is there anybody from WF on this forum ? How do I report a problem to them ?


I had a similar issue. I suspect hardware failure. I had a ton of lightning strikes appear out of the blue which coincided with battery drain. WF replaced the Air unit and it’s been working like a champ ever since.

Yes, WeatherFlow staff are active on the forum. Just send an email to or maybe @dsj or another @WeatherFlow staff member can help you out.

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First set of my Ultimate Lithium batteries in the Air are close to a year with 3.5V. I removed the batteries from the Sky after 6 months and put new set in before I moved the station to a remote location. Sky went off after 3 months. I checked the batteries and 2 were completely dead. I put the old ones back in and am at 3.15V still.I highly suspect the issue is in bad quality of the batteries (despite being so pricey).

I’m currently in my 20th month on the same set of Ultimate Lithium batteries… they must be magical!

Given that my current readings are around 3.15v, and that the voltage has never dropped below 3v, it’s possible that I may make it to 24 months (Oct. 2019) before needing to replace…

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I am still on the original batteries for my AIR. Hoping they will die soon so I can get the incentive to replace them with a SPA :grinning:

Just confirming that my AIR went off-line yesterday as expected (its last reported voltage was 2.2V)

I’ve replaced the AIR’s batteries with a fresh set of Ultimate Lithiums bought from a different supplier this time (previously Amazon, this time Home Depot).

I’ve reported the problem to WF … lets see what happens.

Thanks to everyone who helped with advice. This is a great community.

@iladyman. I’m from Melbourne originally now in the US. Bunnings opened up some stores in Melbourne just before I emmigrated. IIRC they’re pretty similar to a Home Depot here.


I put my first batteries in on 10/28/17. Still haven’t changed them.
Currently showing 2.8 Volts (Good)

On the subject of Air battery life mysteries, it appears that AR-00004424’s batteries have finally expired. I couldn’t tell by the battery card on the web though, since it is reading 3.31 volts and good battery state! A quick perusal of the graph reveals why:


If I didn’t know any better, I would think that this graph captured a resurrection…and those batteries are now in a happier place.

I’m leaving it sit for a few more days before changing the batteries, since this unit has a history of coming back from the dead every previous time that I have written it off for the failure du jour…