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New station up & running

Posted: Mon 15 May 2017 6:54 pm
by mikechristelow
Finally got the Watson W8681 (solar) installed and up and running to replace the badly-behaved and failing TechnoLine Ws2350. Gave me an opportunity to re-open some of the web-page templates I've not worked on for a couple of years...

The new sensor array is mounted approx 7ft above ground level, presently, using the supplied mounting poles and a TV aerial fixing bracket mounted to the concrete fence post. The location is far from ideal but I've lost my confidence for scaling the roof to fit the anemometer to the chimney-stack (as the old arrangement was until it failed). I'm looking to get about 3m of aluminium tube, 19.5mm in diameter, to extend the Watson pole and lift the wind sensors to a better height (tho' still far from ideal). The Watson pole is 20mm in diameter so I'm hoping to sleeve it over the extension pole.

So far I've had only a few false reports of "lost sensor contact" but will need to keep an eye on this as it seems to have troubled some folks badly in the past.

One of the reasons I wanted the Watson was (apart from budget) the solar / UV / Lux data it supports - handy for confirming that the weather is spectacularly dull, as the picture shows :lol:

Re: New station up & running

Posted: Tue 16 May 2017 6:13 am
by vaggos
Two remarks.
If you leave the rain gauge there, you will have the wrong measurements. The air will move the spoon and your station will write rain. You also need solar protection (shield) for the temperature sensor. Otherwise you will have +2 - +4 degrees on the hot days.
And also, change the batteries in your transmiter with better. A lot of people had problems with the the solar / UV / Lux data and a lot of lost contacts. Finally, motst of them put rechargable batteries, with no solar.
You can see mine shield here https://weather.meteoacharnes.gr/cam/cam4/.
Regards

Re: New station up & running

Posted: Tue 16 May 2017 6:58 am
by mikechristelow
Thanks Vaggos. I presume if I extend the wind sensors to a higher location as I intend to, the disturbance to the rain gauge will be eliminated? Is it likely to be a measurable disturbance with the array as I have it at the moment? The note re batteries is helpful, I'm only using the rechargeable ones that came with the station. Are there "better" quality rechargeable ones that you would recommend?
Best wishes, Mike

Re: New station up & running

Posted: Tue 16 May 2017 7:31 am
by vaggos
Dear friend.
If you place the air sensors higher, the rain gauge can also write mm because of the air. Prefer to place the rain gauge firmly on the ground, free from all sides. So, as you have it, by oscillations, you will definitely write more mm.
Clearly there are better rechargeable batteries. Preferred a few more mAh.
Regards.

Re: New station up & running

Posted: Tue 16 May 2017 8:43 am
by AllyCat
Hi,
mikechristelow wrote:Are there "better" quality rechargeable ones that you would recommend?
Unfortunately there is no "good" solution. The 308x (and similar models) solar charging is regulated at 3.0 volts which isn't "optimum" for any type of cell. :(

The "easy" solution is to use a pair of NiMH cells (nominal 1.2 volts each, but they "float" on charge comfortably at 1.5 volts), preferably the "Low Self Discharge" (LSD) or "Hybrid" type. However, you may encounter some "Low battery" warnings and/or poor wireless range. Alternatively, use standard non-Rechargeable Alkalines, which will probably last as long and work as well as the (so-called) "Rechargeable" Alkaline type.

Other possibilities do exist, so If you want more details see this thread or just search this forum for "NiZn".

Cheers, Alan.

Re: New station up & running

Posted: Tue 16 May 2017 9:40 am
by mikechristelow
Hi Vaggos,
I'm limited to where the raingauge can go presently as the garden is having much work done on it and other factors include kids and what the Mrs will tolerate! I'm aware that the proper siting for this component is on the ground but that's not practical at the moment so with all home weather stations, some compromise results.

Thanks AllyCat for the notes re batteries - I'll get a pack of NiZn 1.6v 2500mwh batts and see how things go.

Still got to engineer the lift of the wind instruments yet :-)

Re: New station up & running

Posted: Tue 16 May 2017 10:49 am
by AllyCat
Hi,
mikechristelow wrote:I'll get a pack of NiZn 1.6v 2500mwh batts and see how things go.
Keep us informed how you get on. However, the power drain of the transmitter is so low (and the capacity of NiZn similar to the other technologies) that I wouldn't have expected any cells to go "flat" before Winter 2019, even if they're not being charged!

But I thought I'd check on the Self-Discharge rate of NiZn, which is said to be 13% per month (see here for example). So maybe we'll find out if they're actually being charged usefully in 2018. ;)
mikechristelow wrote:Still got to engineer the lift of the wind instruments yet :-)
Extending the wind cables is generally easy, but ensure that rainwater can't get into the connectors. The problem is what to do about the Solar Pod: For reasonable watts/m2 measurements over the whole day, it may need to be "up with the wind sensors", but physical mounting and extending the cable is much more tricky (6 cores/RJ12, plus the rain cable to be considered). Also, you may need to access the Pod on occasions to use its "Reset" button (and/or cover the PV panel) if/when the microcontroller crashes or "hangs" (which mine has done more than once, even though it's supposed to be the "latest" version).

Cheers, Alan.