Davies new tipping bucket

[The PIT]

I decided to buy one of these as they are supposed to be more accurate.

Typically the weather of course has been fairly dry however when we did get some prolonged rain the results were disappointing so for 10mm of moderate rain it would read 10.7mm.

I checked the gauge and it wasn't quite level so levelled it off however it still typically 0.7mm above the actual rainfall.

No problem there must be a way to calibrate it and believe it or not there isn't a way which seems to be a big oversight by Davies.

At least the old tipping bucket you could adjust it although never really accurate you could get it fairly close the biggest errors coming with heavy rain.

So my advise is stay clear if possible however newer models will be fitted with this unit.

[The PIT]

Got a feeling today it will be reading too low. Been out for a walk and it chucked down and came back to only 3mm on screen which seams wrong

[reef]

I've had two old style Davis rain tipping buckets and both have read around 20% under out of the box. As you say they can be calibrated and once done can be very accurate (mine averages extremely close to a manual gauge).

I'd heard the new spoon versions could read high so have deliberately held off so to hear yours is 7% out and cant be calibrated is quite disappointing. I think they are designed more for areas with extremely heavy rainfall which is when the old style tipper can under read.

[The PIT]

Lack of calibration seems to be the way Davis instruments are going Weatherlink live has very little in the way of calibration and as far as I can see the airlink has none.

[Dorsetbred]

On 30/10/2021 at 20:57, reef said:

I've had two old style Davis rain tipping buckets and both have read around 20% under out of the box. As you say they can be calibrated and once done can be very accurate (mine averages extremely close to a manual gauge).

I'd heard the new spoon versions could read high so have deliberately held off so to hear yours is 7% out and cant be calibrated is quite disappointing. I think they are designed more for areas with extremely heavy rainfall which is when the old style tipper can under read.

Interesting, how do you compare a digital gauge to analogue gauge when it is in the 10th's of a millimetre, is the analogue gauge definition in 10th's of a millimetre?

[Mapantz]

On 14/11/2021 at 16:19, Dorsetbred said:

Interesting, how do you compare a digital gauge to analogue gauge when it is in the 10th's of a millimetre, is the analogue gauge definition in 10th's of a millimetre?

Davis see-saw tippers are supposedly calibrated to take 5.44 ml of water before they make a tip - 0.2 mm. So I guess that knowing  the start value in millilitres means you could compare it to what's in a manual gauge.

1mm of rain in a tipper equates to  27.2 ml in volume, which should be what a manual gauge holds when you pour it in to a measuring device.

I could well be wrong there as I never liked maths. 

[reef]

On 14/11/2021 at 16:54, Mapantz said:

Davis see-saw tippers are supposedly calibrated to take 5.44 ml of water before they make a tip - 0.2 mm. So I guess that knowing  the start value in millilitres means you could compare it to what's in a manual gauge.

1mm of rain in a tipper equates to  27.2 ml in volume, which should be what a manual gauge holds when you pour it in to a measuring device.

I could well be wrong there as I never liked maths. 

Yes, thats pretty much it. For calibration 544ml in an empty plastic bottle with a small hole in the bottom so it slowly drips through and adjust until its as close to 25.4mm as possible.

Edited June 26, 2022 by reef
Very late edit, but realised the figure was wrong upon reading again!

[The PIT]

On 14/11/2021 at 16:19, Dorsetbred said:

Interesting, how do you compare a digital gauge to analogue gauge when it is in the 10th's of a millimetre, is the analogue gauge definition in 10th's of a millimetre?

Pretty simple you pour the analogue rainfall into the measuring gauge. So if I measure 0.1mm rain in the analogue and digital says 0.5mm there's clearly an issue.

The problem with tipping buckets is that splash most of all when there's heavy rain. Although I got the original gauge fairly close it could be miles off in certain conditions. 

[reef]

Bumping this as I've just updated to the tipping spoon as I was doing a temperature/humidity sensor replacement (due to the infamous SHT31 high humidity reading ceiling issue) so thought Id give it a go.

Upon installation and trying the 544ml of water from a bottle test it was less than 2% out, which really surprised me. Ill be interested to see how it performs compared to a manual gauge with actual rainfall (when we actually get some).

[The PIT]

Doesn't do well in heavy rain so Davis really need to redesign it and allow for calibration.

[The PIT]

Recent heavy rain showed up the weakness of the design with it being out by 6% to 8%.

[Mapantz]

Too low or too high? 

[The PIT]

Too High

[Mapantz]

I have had the same problem with 3 of them. It's ridiculous!

I've gone back to the see-saw tipper, and will not be trying another spoon tipper again.

I reported it to the seller, and I get the "we'll contact Davis" email, and then that's it... no reply back, ever.

[reef]

I'm still waiting for some decent rainfall to actually see how mine performs. It was great on the 544ml water test over an hour and again over 15 minutes, however I'm yet to have a real rain event to see what the difference is!

The irony is that it was designed to be better in heavier rain events, so if it is useless at that then its a bit of a failure.

[Evening thunder]

I updated to the new spoon design back at the start of 2021, it seems a touch high but at least I get more consistent readings now compared to my manual gauge, which I could never seem to get with the old tipping mechanism for some reason.

Edited August 24, 2022 by Evening thunder

[The PIT]

4 hours ago, reef said:

I'm still waiting for some decent rainfall to actually see how mine performs. It was great on the 544ml water test over an hour and again over 15 minutes, however I'm yet to have a real rain event to see what the difference is!

The irony is that it was designed to be better in heavier rain events, so if it is useless at that then its a bit of a failure.

It's pretty good in light rain but certainly no better in heavy rain.

[Mapantz]

Quote

Hello

Thank you for your enquiry.

When was your first station purchased? I will refer this to an engineer but if the issue has not been resolved with replacing the tipping mechanism then it points to a Board Fault.

[The PIT]

I take it you haven't chased.

The real problem is that Davis haven't bothered to design in an adjustment which they should as it isn't cheap. They do seem to be going the road we know best which is cheaper support wise but in the long run damaging to the brand name.

[Dorsetbred]

Interesting as they were bought out by AE Instruments, whose market statement is "AE Monitoring is combining global leaders to provide reliable and innovative environmental monitoring and analysis solutions."! Mind you it doesn't include the word ACCURATE or PRECISE.

[Mapantz]

22 hours ago, The PIT said:

I take it you haven't chased.

The real problem is that Davis haven't bothered to design in an adjustment which they should as it isn't cheap. They do seem to be going the road we know best which is cheaper support wise but in the long run damaging to the brand name.

I did reply:

Quote

Hi

With all due respect, it isn’t a problem with the board.

I emailed you last time with a lot of detail on my findings. The evidence is irrefutable, the spoon tipper has an issue. I’ve tried 3 now, and the same problem occurs.

As for referring to an engineer, you said that back in May when I last contacted you, and I heard nothing back.

Regards.

That was Thursday, didn't get a reply back.

[The PIT]

Okay so for yesterdays rainfall the tipping bucket recorded 10.6mm actual amount 9.1mm. Not very good.

[The PIT]

Okay rainfall for the last four days tipping bucket recorded 23.4mm and actual rainfall was 21.5mm. Most of the error was on the 30th when it recorded 16.8mm while the actual rainfall was 15mm. Rainfall on that day was heavy at times. An 8.84% error.

Just been down and did what I was going to do this morning and check whether it's level. It is. I then checked the bucket for rubbish and it was clean however despite the filter a sycamore or ash tree seed had got wedged in the inlet. however this would only slow the rainfall rate down so now that's it gone it it will be interesting too see how it handles the rainfall.

 

Edited October 2, 2022 by The PIT
More info

[The PIT]

Last few days have produced readings of 10.8mm actual 10.3mm 7.8mm actual 7mm so you can see it doesn't perform very well. Badly needs the option to adjust the amount. Can't really recommend the device.

[nuts]

The problem with tilting spoon rain guages, compared to tipping bucket (2) gauges, is that water does not completely drain away from the spoon after a tip.  This means the next tip, (during a continuous rainfall event),, will tip the spoon at less than its calibrated amount.

e.g: 3ml to tip spoon, the next tip already has 0.2ml in spoon, so tips at a further 2.8ml.  This will mean tilting spoon r/guages over-read rainfall accumulation.

For this reason I prefer tipping bucket guages, e.g:  EML ARG 100, however the cost is beyond the reach of most. (cheaper models avlbl e.g: Rainwise Rainew 803-1001.)