Topic: WH40 battery voltage

[Ra1nman]

Didn't want to crash any other WH40 threads, my new WH40 has been running for two days now, new Energizer lithium installed from same pack I know is good. Within the first 30 minutes the battery went from 1.8 to 1.7, then today it dropped to 1.6v. My only comparison is the soil moisture sensor, this has never moved from 1.8v in over a week. Seem to recall reading someone who'd got two WH40's in succession that were draining the batteries, hoping mine is normal

[hiljo]

See if it goes dead in the future. As long as it works, it works right? 

Mine is at 1.7V for a long time now.

[Ra1nman]

See if it goes dead in the future. As long as it works, it works right? 

Mine is at 1.7V for a long time now.

Sounds promising, it dropped to 1.6 then went back to 1.7 since so better result

On a side note, your website is very nice tidy job. Might look into those gauges and charts myself in time.

[Rover1822]

I believe Ra1nman was referring to this thread https://www.wxforum.net/index.php?topic=44280.msg450442#msg450442

And we are still waiting for OP of that one to let us know about his experiences with the 3rd one which probably still in shipping.

I can say , the batteries in mine last at least a year, I don't change them because of low battery (which I would have to test manually), rather more of a schedule to just change them.

[hiljo]

On a side note, your website is very nice tidy job. Might look into those gauges and charts myself in time.

Thanks for the compliment! 

I can say , the batteries in mine last at least a year, I don't change them because of low battery (which I would have to test manually), rather more of a schedule to just change them.

Thats one way to do it. Altough my lithium batteries are quite expensive. So I've set up alarms for my sensors for when the batteries are low (locally and on ecowitt.net).

[Rover1822]

Grin, I have first gen WH40s, they do not report battery voltages. That became available in later versions.

[hiljo]

Grin, I have first gen WH40s, they do not report battery voltages. That became available in later versions.

True. Thats a real bummer
Then still I'd wait for it to go dead . But in my case, It's at 1.5m height and very easy accessible

[Rover1822]

Grin, I have first gen WH40s, they do not report battery voltages. That became available in later versions.

True. Thats a real bummer
Then still I'd wait for it to go dead . But in my case, It's at 1.5m height and very easy accessible

Well .. LOL... I'm not buying new ones just for that. LOL. I guess, I could just wait... sigh

[BoDuke]

Another thing to note is the earlier WH40 units don't send battery voltage to the gateway whereas the newer units do.

Are there more reports of the earlier or later WH40 units with excessive battery usage?  I don't know.  If we could figure that out, we could look to see if there is any correlation or not.  Of course, even then it could just be coincidental.

[olicat]

Hi!

My WH40 has been active here since 15.04.2022. The displayed voltage is now - after almost 9 months at 1.7 (Lithium) - so it has only decreased by 0.1 during this time.

Oliver

[Rover1822]

The good news, as I have gen one units, is that the still are working fine. I don't have specific dates, I don't expect any less from newer units.

[Ra1nman]

I believe Ra1nman was referring to this thread https://www.wxforum.net/index.php?topic=44280.msg450442#msg450442

And we are still waiting for OP of that one to let us know about his experiences with the 3rd one which probably still in shipping.

That was the one, I suddenly thought it had dropped from 1.8 to 1.6 in two days, but then it went back to 1.7 again. Mine is the newer version which displays voltage, of course a test meter would be a safer bet for accurate reading. Hope mine is a good one and continues to plod along.

[Ra1nman]

Hi!

My WH40 has been active here since 15.04.2022. The displayed voltage is now - after almost 9 months at 1.7 (Lithium) - so it has only decreased by 0.1 during this time.

Oliver

This sounds promising to me, all being well mine should steady up at 1.6-1.7v for the months ahead. I went with Energizer lithium since they seemed best bet in my region.

[Ra1nman]

Grin, I have first gen WH40s, they do not report battery voltages. That became available in later versions.

True. Thats a real bummer
Then still I'd wait for it to go dead . But in my case, It's at 1.5m height and very easy accessible

My WH40 is only around 0.5m height in a semi temporary location at the moment for testing, so nice and easy access also It will get moved shortly now all seems to be working OK, intending to stick to around 0.5m depending on where it finally ends up.

[GeeEmm]

Grin, I have first gen WH40s, they do not report battery voltages. That became available in later versions.

Rover, how do you tell which generation, and how many generations are there?  Nothing I can find in the way of a serial number, unless it is the bar code on the box?  If mine is one that reports battery voltage, where do I find the info?

As you know from my WH40 thread, I have developed what is probably a very unhealthy interest in this sensor and its quirks ...

BTW, I have updated my thread, it only says the new one (no3) is working to spec - so far (an hour or two), so good ...

[hiljo]

Rover, how do you tell which generation, and how many generations are there?

I know there are versions who report vs. do not report battery voltage and there are versions with a reed switch vs. hall effect switch. If the hall switch came together with battery reporting, I don't know. So there are at least 2 versions, but maybe even 4 or more (?)..

[Ra1nman]

My WH40 now seems to have settled at 1.7v and soil moisture also steady at 1.7v, these both have Energizer ultimate lithium cells installed.

[slybarman]

Is voltage dropping with temp? That wouldn't be entirely unexpected. Lithiums hold voltage better than alkaline, but even lithiums struggle as it gets colder.

[Ra1nman]

Is voltage dropping with temp? That wouldn't be entirely unexpected. Lithiums hold voltage better than alkaline, but even lithiums struggle as it gets colder.

Exactly that, my brain engaged soon after I posted and I suspected as much, sure enough overnight it was flickering down to 1.6 then mid morning back to 1.7. As you say, even lithiums will struggle below zero. Thanks for posting and apologies I did not spot the correlation sooner, at least I don't have an engineering background, now that would be embarrassing