Author Topic: Davis Vantage Pro2 - Super Capacitor Replacement - DIY  (Read 3013 times)

0 Members and 1 Guest are viewing this topic.

Offline Old Tele man

  • Singing in the rain...
  • Forecaster
  • *****
  • Posts: 1346
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #50 on: May 24, 2018, 05:46:21 PM »
The voltage is limited by the maximum possible sunlight intensity (i.e., physics of the solar cell).
Ah-h-h-h, but too high VOLTAGE is definitely NOT healthy for all the IC devices that are ALSO being fed from that supercap.

Too high voltage is also not healthy for the supercap. 

What's the output voltage (at maximum solar intensity) of the Davis solar panel supplied with the VP2?  OK, subtract one diode-drop (0.7 volts) (because of the reverse-current protection required). 

What voltage do you come up with?
I've measured 2.17 to 2.27Vdc...but you have to remember that voltage is "doubled" to get it up to the 4.5-5Vdc used by the IC's.
SYS: Davis VP2 Vue/WL-IP & Envoy8X/WL-USB;
DBX1 Precision Digital Barograph
CWOP: DW6988 - 2 miles NNE of Cortaro, AZ
WU - KAZTUCSO202, Countryside

Offline dalecoy

  • Forecaster
  • *****
  • Posts: 6313
    • Lee's Summit, MO
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #51 on: May 24, 2018, 05:49:46 PM »
Conclusion: it's safe.

Offline Old Tele man

  • Singing in the rain...
  • Forecaster
  • *****
  • Posts: 1346
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #52 on: May 24, 2018, 07:11:45 PM »
Conclusion: it's safe.
Not 100% necessarily so...some supercaps have 'max' operating voltage rating of 2.5Vdc while others have 2.7Vdc. This is a very narrow range and heat exacerbates this "tight" range.
SYS: Davis VP2 Vue/WL-IP & Envoy8X/WL-USB;
DBX1 Precision Digital Barograph
CWOP: DW6988 - 2 miles NNE of Cortaro, AZ
WU - KAZTUCSO202, Countryside

Offline dalecoy

  • Forecaster
  • *****
  • Posts: 6313
    • Lee's Summit, MO
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #53 on: May 24, 2018, 08:49:15 PM »
Conclusion: it's safe.
Not 100% necessarily so...some supercaps have 'max' operating voltage rating of 2.5Vdc while others have 2.7Vdc. This is a very narrow range and heat exacerbates this "tight" range.

I thought we were discussing:
About the only *true* problem with using two supercaps is the *possibility* of overloading/working whatever 'regulating/limiting' circuitry DAVIS has designed-in (to ensure too much voltage doesn't zap ICs) between the solar cell and the supercap. Something designed to handle ONE supercap may not be strong enough to handle charging TWO supercaps...just depends upon how much "design margin" DAVIS incorporated.

But there isn't any circuitry between the solar cell and the supercap, except a diode (reverse-current protection) which reduces the solar cell voltage.

You said about the solar cell:
I've measured 2.17 to 2.27Vdc...but you have to remember that voltage is "doubled" to get it up to the 4.5-5Vdc used by the IC's.

And as you said, the "supercaps have 'max' operating voltage rating of 2.5Vdc while others have 2.7Vdc." - so, it looks "safe" to me.

Offline Zoandar

  • Member
  • *
  • Posts: 23
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #54 on: June 25, 2018, 04:33:21 PM »
FYI: Ryan at scaledinstruments.com has put together a nicely done pic-heavy super cap replacement tutorial.

This is a very nice tutorial!

As I was reading it and viewing the pics, I had the thought "if you snipped the leads of the OEM cap, you could solder in a new one and not have to go through all the steps to remove the board from the housing". Imagine my surprise as he eventually snipped the leads and did just that! :) Being very experienced at soldering, I am pretty sure I can change mine out without even removing the ISS housing from its retractable pole I have it mounted on. I think I'll clip a couple hemostats on the OEM leads to wick away the soldering heat as the new cap is soldered into place.

I wonder if this capacitor failure issue, dating back to about the same time all those PC motherboards had bad caps, is related to the prolific failure of those motherboard caps in some way - i.e.  overall cheesy cap production for many different styles at that time?

Offline dalecoy

  • Forecaster
  • *****
  • Posts: 6313
    • Lee's Summit, MO
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #55 on: June 25, 2018, 04:57:39 PM »
I wonder if this capacitor failure issue, dating back to about the same time all those PC motherboards had bad caps, is related to the prolific failure of those motherboard caps in some way - i.e.  overall cheesy cap production for many different styles at that time?

My understanding is that a large percentage of the failures were related to production - bending the leads too close to the seal at the end of the case, or putting stress on that seal area.  The result was leakage of the electrolyte from the supercap (and often corrosion of the board).  This could have been caught by QA if specified, of course.  Others simply poor manufacturing quality of the supercap, as you said.

I hadn't considered whether this supercap situation might be related to the rash of "regular" electrolytic capacitor failures on motherboards, TVs, etc.  That's an interesting thought.

Offline Old Tele man

  • Singing in the rain...
  • Forecaster
  • *****
  • Posts: 1346
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #56 on: June 25, 2018, 05:27:55 PM »
I wonder if this capacitor failure issue, dating back to about the same time all those PC motherboards had bad caps, is related to the prolific failure of those motherboard caps in some way - i.e.  overall cheesy cap production for many different styles at that time?

My understanding is that a large percentage of the failures were related to production - bending the leads too close to the seal at the end of the case, or putting stress on that seal area.  The result was leakage of the electrolyte from the supercap (and often corrosion of the board).  This could have been caught by QA if specified, of course.  Others simply poor manufacturing quality of the supercap, as you said.

I hadn't considered whether this supercap situation might be related to the rash of "regular" electrolytic capacitor failures on motherboards, TVs, etc.  That's an interesting thought.
Wasn't too long ago that the Military Defense industry ALSO ran into a rash of capacitor failures that were traced to Chinese origins...and poor QC control of both process AND product.
« Last Edit: June 26, 2018, 07:08:32 PM by Old Tele man »
SYS: Davis VP2 Vue/WL-IP & Envoy8X/WL-USB;
DBX1 Precision Digital Barograph
CWOP: DW6988 - 2 miles NNE of Cortaro, AZ
WU - KAZTUCSO202, Countryside

Offline Intheswamp

  • Early on one frosty morn'...
  • Forecaster
  • *****
  • Posts: 1374
  • Sure...I know enough to be dangerous, now.
    • Beeweather
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #57 on: June 26, 2018, 08:42:58 AM »
Well, my station just clicked over the 5-year mark.  My how time flies!!!

I bought replacement batteries for the ISS a year or two after I installed the station.  You know, "Be prepared" and all that stuff.  Several of you suggested holding off on buying the batteries.  They were cheap, shipping was more than the batteries so I bought a few of them (still cheaper than buying one at Wallyworld).

The new batteries are still in their shipping package "somewhere".  Ya'll were right about waiting to buy batteries...the station is still running on the OE battery and I've had no issue with the supercap.  When the supercap craps out on me I'll probably just stretch a LONG stretch of extension cords out to the ISS and clip the old cap out and solder the new one in situ. 

I hope I didn't just jinx myself.

Davis VP2, v3.12
Cumulus v1.9.4  Build 1079
Today's weather beats no weather at all!
www.beeweather.com

Offline Aardvark

  • Forecaster
  • *****
  • Posts: 2039
  • www.desmoinesweather.org
    • Des Moines Iowa Weather and Climate
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #58 on: June 26, 2018, 10:16:02 AM »
I replace the CR123A annually. I buy them in bulk.  I have 8 stations, 4 -1000 lumen flashlights (Light up the night, wait is that a squirrel in combat gear in that tree?)   

To purchase them at the hardware store, drug store is too dang expensive.  I use either Surefire or Titanium Innovations  and they last.  I pay about a dollar (US) for the Titanium Innovations and 2 bucks for Surefire . I get mine from :https://www.batteryjunction.com  .

Normally I wait until the console says the battery is low and needs to be replaced, but the weather is a big factor.  If I have experienced a cold, cloudy winter, I will replace the battery in the spring, or if we have had an exceptionally intense bout of solar radiation I replace the ISS battery in the fall.  Sure you can wait until you get "Low battery on station 1"  and replace it then. but not to replace it, well when I do I can inspect the ISS case, check for corrosion.   

As far as the Supercap.   When I had mine bite the dust, I noticed that the corrosion was very near the cap bottom.   I also noticed that the angle  was tight, so when I replace mine, I used a wider bend, also put a bit of double sided tape, like  they sell for mounting things to a wall.  I read somewhere that putting that between the replacement cap and the circuit board  would reduce shock by vibration.  I have not idea why ,  it isn't as if the thing bounces around.  But I did.

I did ask Davis about the second set of holes for a second supercap.  Again  not to use the 2nd .  It was there by mistake.  IF two are used, you don't get twice the storage but half.  The charging circuit of the ISS isn't strong enough to gather enough energy to store, so it can muster about half and that would be the same as  the one.  As for it being a spare, nada.

I buy my super cap from Scaled Instruments  and they are not that expensive.  Do use a heat sink and a low watt soldering iron so not to fry the components.

OK... My two cents from my experience with the whole thing.
Davis VP2 Plus; 24h  FARS;  Soil Moisture/Temp Station;Weatherlink ;
https://www.desmoinesweather.org

Offline miraculon

  • Sunrise Side Weather
  • Forecaster
  • *****
  • Posts: 3208
  • KE8DAF
    • Sunrise Side Weather in Rogers City MI USA
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #59 on: June 26, 2018, 05:09:30 PM »
I replace the CR123A annually. I buy them in bulk.  I have 8 stations, 4 -1000 lumen flashlights (Light up the night, wait is that a squirrel in combat gear in that tree?)   

To purchase them at the hardware store, drug store is too dang expensive.  I use either Surefire or Titanium Innovations  and they last.  I pay about a dollar (US) for the Titanium Innovations and 2 bucks for Surefire . I get mine from :https://www.batteryjunction.com  .

Normally I wait until the console says the battery is low and needs to be replaced, but the weather is a big factor.  If I have experienced a cold, cloudy winter, I will replace the battery in the spring, or if we have had an exceptionally intense bout of solar radiation I replace the ISS battery in the fall.  Sure you can wait until you get "Low battery on station 1"  and replace it then. but not to replace it, well when I do I can inspect the ISS case, check for corrosion.   

I also get my batteries from batteryjunction.com. I decided to use the Surefire for the roof-mounted items (anemometers, repeater) and the Titanium Innovations ones for the ground mounted stuff. Mainly because I bought a whole crowd of the latter and needed to use them somewhere. Both work fine, but I thought that the surefire would be good for the transmitters that are not easily accessible, especially in the winter.

Greg H.


Blitzortung Stations #706 and #1682
CoCoRaHS: MI-PI-1
CWOP: CW4114 and KE8DAF-13
WU: KMIROGER7
Amateur Radio Callsign: KE8DAF

Offline Aardvark

  • Forecaster
  • *****
  • Posts: 2039
  • www.desmoinesweather.org
    • Des Moines Iowa Weather and Climate
Re: Davis Vantage Pro2 - Super Capacitor Replacement - DIY
« Reply #60 on: June 26, 2018, 07:00:33 PM »
I replace the CR123A annually. I buy them in bulk.  I have 8 stations, 4 -1000 lumen flashlights (Light up the night, wait is that a squirrel in combat gear in that tree?)   

To purchase them at the hardware store, drug store is too dang expensive.  I use either Surefire or Titanium Innovations  and they last.  I pay about a dollar (US) for the Titanium Innovations and 2 bucks for Surefire . I get mine from :https://www.batteryjunction.com  .

Normally I wait until the console says the battery is low and needs to be replaced, but the weather is a big factor.  If I have experienced a cold, cloudy winter, I will replace the battery in the spring, or if we have had an exceptionally intense bout of solar radiation I replace the ISS battery in the fall.  Sure you can wait until you get "Low battery on station 1"  and replace it then. but not to replace it, well when I do I can inspect the ISS case, check for corrosion.   

I also get my batteries from batteryjunction.com. I decided to use the Surefire for the roof-mounted items (anemometers, repeater) and the Titanium Innovations ones for the ground mounted stuff. Mainly because I bought a whole crowd of the latter and needed to use them somewhere. Both work fine, but I thought that the surefire would be good for the transmitters that are not easily accessible, especially in the winter.

Greg H.

My transmitters are on the ground or at least where I can get at them. We have a steel roof that looks like shingle and i am told one can do a nifty slide off and ground splatter,  Hence the ground.   I prefer the surfire, not sure why but I do.  And the 1000 lumen flash lights ...  heh, heh, heh...
Davis VP2 Plus; 24h  FARS;  Soil Moisture/Temp Station;Weatherlink ;
https://www.desmoinesweather.org

 

anything