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Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 8:38 am
by freddie
I have a separate Davis anemometer transmitter for my VP2 anemometer. Over the weekend I have had to replace its battery twice. The first time was because it was the first replacement I have made in eight years, so assumed the battery had finally given up the ghost. The second time was because I was unsure of whether the first replacement battery had any life left in it. The third (new) battery lasted 24 hours. Does the anemometer transmitter have a super capacitor in it similar to the VP2's ISS? If so, I think it may have failed. If this diagnosis is correct, is it easy to replace?

Re: Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 9:13 am
by Hobbyist
Hi Freddie I am no expert on the Davis system as I am, at present, running an Instromet unit. However I have just purchased a Davis Wireless set-up and a Windspeed solar transmitter was part of my kit. From what I have read a 'fully' populated ISS solar unit can run with no sunlight for 8 months on the battery.

The Wind transmitter does have a supercapacitor fitted. I must admit,to me, 24 hours seems too short a time span for a single windspeed/direction unit to run on the battery. Possibly poor battery batch or poor battery connections on the unit itself?

Hope that helps

Dave

Re: Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 10:18 am
by mcrossley
Agree, that has drained the battery too fast, something is wrong. It could be the capacitor though, depends how it has failed.

It needs opening up and checking for water damage etc.

The caps are pretty easy to replace, just be aware they are fairly delicate. I'd snip the legs of the existing cap after the bend - so that they still have the right-angle in them. Then when replacing you do not need to bend the legs of the new one. Just glue it to the board, and solder the new caps straight legs to the existing stubs then trim off the excess.

You can order them on eBay pretty cheap.

Re: Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 11:49 am
by Mapantz
Isn't the super cap to hold charge that has built up from solar radiation?

Even if that has failed, shouldn't the battery be able to keep the transmitter going for quite some time?

Re: Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 12:00 pm
by mcrossley
Indeed, but if it has failed in way that leaves a resistance across the supply it could be draining the battery. We don't have a circuit diagram to be sure though.

It could be corrosion elsewhere of course.

Re: Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 12:36 pm
by laulau
A faulty capacitor !
Condensateur-10F-pour-ISS-07345.978___2.jpg
not mine but i had to replace the capacitor a month ago because the transmitter was stopping during night even with a new battery!

Re: Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 8:53 pm
by prodata
The anemometer Tx board is identical to the main ISS board and so any issues and features in the ISS also read across to the 6332 Anemo Tx board.

More generally, Davis only make two types of transmitter board for the VP2 stations. One is the ISS type (all wireless VP2 ISS versions; 6332; 6372; 6382) and the other is for the leaf/soil/temperature transmitter (6345).

https://www.manula.com/manuals/pws/davi ... ard-faults

https://www.manula.com/manuals/pws/davi ... cap-faults

Both topics probably need a review & update (but the basic info should be OK) - I wonder when I might have time to do that :?

Re: Davis anemometer transmitter problems

Posted: Tue 31 Mar 2020 9:25 pm
by RayProudfoot
Just for info my Anemometer transmitter is still going strong since its purchase in April 2009 from ProData. Located on a ESE wall so it gets a decent amount of sunshine. I replaced the Duracell battery in January. Can’t remember how many times over the years so not that many I guess.

Re: Davis anemometer transmitter problems

Posted: Wed 01 Apr 2020 1:20 pm
by freddie
Further to this - I re-seated the battery in the unit and was rewarded with about two hours worth of data recording. Loose connection?

Re: Davis anemometer transmitter problems

Posted: Wed 01 Apr 2020 4:07 pm
by prodata
freddie wrote: Wed 01 Apr 2020 1:20 pm Further to this - I re-seated the battery in the unit and was rewarded with about two hours worth of data recording. Loose connection?
Possible, but v unlikely. Whats does a visual check of the supercap indicate - clean leads or some exudate?

Re: Davis anemometer transmitter problems

Posted: Wed 01 Apr 2020 5:16 pm
by freddie
prodata wrote: Wed 01 Apr 2020 4:07 pmWhats does a visual check of the supercap indicate - clean leads or some exudate?
It looks very clean to my unpracticed eye.
IMG_20200401_175801.jpg
IMG_20200401_175808.jpg

Re: Davis anemometer transmitter problems

Posted: Wed 01 Apr 2020 6:30 pm
by prodata
Hmm, that looks OK, but unfortunately it's not a definitive test - if you can see gunge on one of the leads then the supercap is likely to be shot, but it does also sometimes fail without visible signs.

You haven't explicitly said, but I presume that you're losing data from the ISS (ie rather than just getting a low battery warning)? But assuming so, then I'm afraid that a new SIM board (or replacing just the supercap to see if this is the problem) is likely to be the only long-term answer.

Re: Davis anemometer transmitter problems

Posted: Wed 01 Apr 2020 6:39 pm
by freddie
prodata wrote: Wed 01 Apr 2020 6:30 pm Hmm, that looks OK, but unfortunately it's not a definitive test - if you can see gunge on one of the leads then the supercap is likely to be shot, but it does also sometimes fail without visible signs.

You haven't explicitly said, but I presume that you're losing data from the ISS (ie rather than just getting a low battery warning)? But assuming so, then I'm afraid that a new SIM board (or replacing just the supercap to see if this is the problem) is likely to be the only long-term answer.
Couldn't see any gunge, they looked clean.

Not sure if you get low battery warnings from the standalone transmitter - I have never seen one on my console. I have seen low battery warnings from the ISS in the past ... I think!

I don't understand why I got that 2-hour burst of data when I re-seated the battery yesterday, though.

Re: Davis anemometer transmitter problems

Posted: Wed 01 Apr 2020 7:02 pm
by prodata
freddie wrote: Wed 01 Apr 2020 6:39 pm Not sure if you get low battery warnings from the standalone transmitter - I have never seen one on my console. I have seen low battery warnings from the ISS in the past ... I think!
Yes, you should do - the console ticker should say 'Low battery on station 2' or something like that
I don't understand why I got that 2-hour burst of data when I re-seated the battery yesterday, though.
The sun wasn't out for that 2hr period was it? But otherwise I agree it's a bit odd. However, if you've tried all the obvious things like cleaning the battery contacts then IME while there can be a variety of odd symptoms from a failing SIM board or supercap you often have to end up having to replace either the supercap or the complete board.

Re: Davis anemometer transmitter problems

Posted: Fri 03 Apr 2020 7:01 am
by freddie
prodata wrote: Wed 01 Apr 2020 7:02 pm
freddie wrote: Wed 01 Apr 2020 6:39 pm]I don't understand why I got that 2-hour burst of data when I re-seated the battery yesterday, though.
The sun wasn't out for that 2hr period was it?
No, it was an overcast day.
prodata wrote: Wed 01 Apr 2020 7:02 pmBut otherwise I agree it's a bit odd. However, if you've tried all the obvious things like cleaning the battery contacts then IME while there can be a variety of odd symptoms from a failing SIM board or supercap you often have to end up having to replace either the supercap or the complete board.
Okay, so I have got some other odd symptoms. Replaced the battery yesterday (2nd) at around 1000 UTC. No effect noticed. Then it sprung into life around 1815 UTC and continued overnight until now. This sounds brilliant, but it was a fairly benign night with some breeze during the evening and very little wind in the second half of the night. Yet it has recorded gusts to 13 knots over the past couple of hours. I would've definitely noticed that as I've been outside. Intrigued, I looked back at the last week of values and see that I had some large gusts recorded on Sunday - and when I say large I mean around 70 knots, the sort of values you would definitely notice! There were similar fake gusts on Saturday too. Previous to Saturday all appears well with sensible values.

Do these fake large gusts point to supercap failure as well?