Author Topic: How to test Super Cap?  (Read 1394 times)

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Offline AA1ZA

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How to test Super Cap?
« on: October 21, 2018, 10:20:34 PM »
So I just replaced both the solar panel and super cap inside my wireless ISS' transmitter.   I then ran it for a day in full sunshine without the battery installed.  By 7pm - about 30 mins after the sun had set  - the ISS went dead again...

Question:  Is running a test like this without the battery installed a legitimate way of testing the super cap's integrity to power the ISS on its own through most of the night?   Or does it always need the battery installed?   And in that case, is the only way to tell that one still has a charging / super cap problem the discovery some 8 months down the line that the battery needs replacement again?
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Offline dalecoy

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Re: How to test Super Cap?
« Reply #1 on: October 21, 2018, 11:53:50 PM »
So I just replaced both the solar panel and super cap inside my wireless ISS' transmitter.   I then ran it for a day in full sunshine without the battery installed.  By 7pm - about 30 mins after the sun had set  - the ISS went dead again...

Question:  Is running a test like this without the battery installed a legitimate way of testing the super cap's integrity to power the ISS on its own through most of the night?   Or does it always need the battery installed?   And in that case, is the only way to tell that one still has a charging / super cap problem the discovery some 8 months down the line that the battery needs replacement again?

Why did you do that?  What were the symptoms before the replacement?  Is this just a standard ISS (no extra stuff, etc.)?

That is not a way to "test the super cap's integrity", regardless of whether the battery is or is not installed.

Assuming that you installed the correct new supercap correctly, you have just proved that there is something else wrong with that ISS.
« Last Edit: October 21, 2018, 11:59:01 PM by dalecoy »

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #2 on: October 22, 2018, 12:33:38 AM »
This is the standard wireless 6152 with envoy.    I bought it used.  The battery needed replacement.   The transmitter housing seemed weathered and brittle and so I replaced it in its entirety (incl. solar panel).  While I was at it, I decided to buy and install a new super cap as well.   (Yes, I got its polarity right and I did not bend its legs at all - and I know how to solder)

Before I mount it on a pole, I'd very much like to know all is good and that I won't be having to pull it down anytime soon again for an earlier than expected battery replacement.

So if that is not the way to test it, which is?   And if you say that I've just proven that something else is wrong, then what does that say about your first statement?   

My understanding is that the super cap's job is to power it for up to about 12 hrs without sunlight; after depletion of its charge, the battery should take over.    What have I done wrong in my test and how else can I test the solar panel / super cap combination's effectiveness ?





« Last Edit: October 22, 2018, 12:41:56 AM by AA1ZA »
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Offline AA1ZA

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Re: How to test Super Cap?
« Reply #3 on: October 22, 2018, 12:43:51 AM »
Has anyone else tested their ISS this way without the battery installed to see how long it would last into the night?   If so, kindly let me know your result.   Thank you.
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Offline SnowHiker

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Re: How to test Super Cap?
« Reply #4 on: October 22, 2018, 02:42:10 AM »
Has anyone else tested their ISS this way without the battery installed to see how long it would last into the night?   If so, kindly let me know your result.   Thank you.
On an original VP (not VP2) I've run a soil temp/moisture station without a battery installed (soil moisture and temp didn't change enough for me to be concerned if it quit for an hour or so at night).  The supercap did in fact power the station most of the night, even in winter, when it was new.

So I would expect a regular ISS on a VP2 to do similar.  In any case, I'm sure it should last for much longer than 30 minutes or so after sundown after a full day in the sun.  Unless they've made some other "improvements" on the VP2.  :-)

So if it's working well off of the solar panel during the day, but not at night, my first guess would be that you have a bad supercap, but since you've just installed a new one, I don't know.

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #5 on: October 22, 2018, 09:55:29 AM »
Thank you very much, SnowHiker.    I appreciate your confirmation.

Anyone else who has tested (or has run) a VP2 like that perhaps?
« Last Edit: October 22, 2018, 09:59:01 AM by AA1ZA »
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Offline dalecoy

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Re: How to test Super Cap?
« Reply #6 on: October 22, 2018, 10:34:52 AM »
This is the standard wireless 6152 with envoy.    I bought it used.  The battery needed replacement.   The transmitter housing seemed weathered and brittle and so I replaced it in its entirety (incl. solar panel).  While I was at it, I decided to buy and install a new super cap as well.   (Yes, I got its polarity right and I did not bend its legs at all - and I know how to solder)

Before I mount it on a pole, I'd very much like to know all is good and that I won't be having to pull it down anytime soon again for an earlier than expected battery replacement.

So if that is not the way to test it, which is?   And if you say that I've just proven that something else is wrong, then what does that say about your first statement?   

My understanding is that the super cap's job is to power it for up to about 12 hrs without sunlight; after depletion of its charge, the battery should take over.    What have I done wrong in my test and how else can I test the solar panel / super cap combination's effectiveness ?

There are a large number of components in the ISS.  I did understand your objective - and your test apparently proved that the ISS/solar panel/supercap combination will not work (more than a few minutes) at night.

Assume (for example) some internal fault in the ISS that prevents the good solar panel from charging that good supercap.  Same result.

Assume (for example) some internal fault in the ISS that causes the transmitter to transmit continually, rather than in short bursts every few seconds.  Quickly draining the supercap.  Same result.

Assume (for example) a fault in the humidity circuitry that drains the supercap.   Etc.......

You say "standard wireless 6152" - Just out of curiosity, was the anemometer connected?  How was the data? 

Bottom line:  You performed a test that shows: 1.  If the test WORKS, then it proves that the solar panel and supercap WORK.  2.  If it FAILS, it does NOT prove what's wrong.

And no, I don't know of a way to test the solar panel and supercap CONNECTED TO THE ISS.

*BUT* - I'm GUESSING, since the solar panel and supercap are new, and you installed them properly, then those two components are good.  And something else in the ISS is faulty.

I'm sorry I can't be more helpful.

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #7 on: October 22, 2018, 11:02:36 AM »
Thank you, Dalecoy.   Yes, I agree with you.  The purpose of my testing was to confirm the solar panel / supercap combination works right, or that it doesn't (implicating a number of other possible reasons why that might be the case...).
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Offline dalecoy

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Re: How to test Super Cap?
« Reply #8 on: October 22, 2018, 12:14:03 PM »
Thank you, Dalecoy.   Yes, I agree with you.  The purpose of my testing was to confirm the solar panel / supercap combination works right, or that it doesn't (implicating a number of other possible reasons why that might be the case...).

Did you perform the same test BEFORE you replaced the two components?  Same result?

Technically, replacing TWO things at the same time leaves some question - you could "UNreplace" the solar panel and see what happens.  But I'm still GUESSING that there's some other internal problem with the ISS (or t/h sensor or anemometer or ...).

Offline rdsman

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Re: How to test Super Cap?
« Reply #9 on: October 22, 2018, 12:26:15 PM »
Quote
I then ran it for a day in full sunshine......

A few other simple tests:

Try again and see if the supercap somewhat approaches the 2.7 volt rating after being in the sun.  If it does the charging portion is probably good.   

Measure the current draw off of the battery - should be near 0 except a small kick every ~2.5 seconds - would eliminate excessive current being drawn by the ISS.  If it is drawing constant current, unplug sensors to narrow it down to the ISS transmitter itself.

That's where I would start....


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Offline dalecoy

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Re: How to test Super Cap?
« Reply #10 on: October 22, 2018, 01:05:16 PM »
Another simple question:  What's the little LED on the ISS board doing?  On all the time?  Blinking once every 2.5 seconds?

Do you have a voltmeter?  If so, what's the voltage of the solar panel in full sunlight when it is DISconnected?  And when it is connected to the ISS?

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #11 on: October 22, 2018, 01:46:39 PM »
Thank you, rdsman.  Those are very useful suggestions which I'll definitely try out next.

It's worth noting that I have replaced the anemometer as well, since the bearing on the one that came with it was worn.   (It was the old type and so I believe I couldn't just replace the bearing itself).  So if excessive draining would be sensor related, I would expect it to be coming from the rain and/or humidity/temperature sensors rather.

Dalecoy, yes, when I got the station I measured the battery and it was sitting around 2.23 V.  At that time I incorrectly assumed it to be a rechargeable battery and so I did not think much of re-inserting it with the hope that it should charge up again.   

So at first, I simply fired it up with the supercap and battery that came with it.  Initially it would keep going through most of the night, but would go dead +/- 2 or 3 hours around sunrise.   However, that duration increased over the following days to the point that the SIM was dead by around 8 pm already.   That's when I pulled out the battery and tested it - it measured 0.8V only.    (And that's when I also discovered that these weren't rechargeables...)

While I was waiting on the replacement battery to arrive, I ran the station without its SIM battery; with the old supercap + new solar panel.   As soon as the sun set, the SIM would be dead also.   There were no signs of cap leakage or any other sign on the circuit board for that matter, that made me suspicious.    But I went ahead to order and replace the supercap nonetheless.  I replaced it with an exact replica:  Nesscap 2.7V 10F.

This is where I'm at now - trying to make sure all is well before I mount it - inbetween 7" of rain that came down last week, etc...    :?

I guess I also have the option to run DC up the pole.  But I read elsewhere on this forum that some wireless units would act up and give erroneous readings if the SIM gets powered externally... 
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Offline AA1ZA

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Re: How to test Super Cap?
« Reply #12 on: October 22, 2018, 01:51:28 PM »
Dalecoy, to be honest, I have not yet noticed or monitored the LED you reference.   I shall definitely check it out - thanks.   

I can confirm though that the DIP switches are all set to zero, i.e. the SIM is not set up to run a transmitter test or anything like that.

As said, the solar panel is brand new.   I can do the test you suggest, however, the station remains on during sunlight hours without a battery installed.   So one would expect the solar panel to be good, I guess.
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Offline johnd

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Re: How to test Super Cap?
« Reply #13 on: October 22, 2018, 02:12:35 PM »
It seems to be reasonably common that replacing a supercap that has become faulty does not restore the board to full operation. I can only guess that a faulty supercap (or maybe one that's been seriously faulty for a while) sometimes damages some other part of the SIM board circuitry, but quite what I've no idea - it's just an observation across many such boards.

If you're comfortable doing it then replacing a faulty supercap is always worth doing as a first go at fixing the problem, but don't be surprised if the issue isn't permanently fixed. I'd guess that maybe 30-40% of such faults end up needing a replacement SIM board.
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Offline dalecoy

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Re: How to test Super Cap?
« Reply #14 on: October 22, 2018, 02:14:08 PM »

Thanks for the more complete description of events.

Solar panel good, presume supercap is good.  Simple test:  unplug *ALL* sensors (anemometer, rain, t/h), see what happens tonight.  (also observe that blinking LED, but I suspect it's 2.5 seconds blinking).

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #15 on: October 22, 2018, 02:23:22 PM »
Thank you, Johnd and dalecoy.

That'll be a bummer if the cap shorted and the SIM board got damaged.  Wish I had a circuit diagram so I could check out likely damaged components in such a case.   

I guess, unless the board draws excessive current that I cannot fix in any other way (eg. replace an offending sensor), that I could also consider running DC up to the SIM (cheaper option than having to replace the SIM board).
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Offline dalecoy

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Re: How to test Super Cap?
« Reply #16 on: October 22, 2018, 03:43:38 PM »
Thank you, Johnd and dalecoy.

That'll be a bummer if the cap shorted and the SIM board got damaged.  Wish I had a circuit diagram so I could check out likely damaged components in such a case.   

I guess, unless the board draws excessive current that I cannot fix in any other way (eg. replace an offending sensor), that I could also consider running DC up to the SIM (cheaper option than having to replace the SIM board).

There are a lot of things in addition to the supercap that could go wrong.  For one simple example, a nearby lightning strike could cause a diode to fail (open or shorted), or damage the transmitter.  Or the rain gauge magnetic switch could have a problem. 

DC to the SIM is easy - buy an additional power supply for the console.  It's the same connection and voltage.

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #17 on: October 22, 2018, 06:46:28 PM »


There are a lot of things in addition to the supercap that could go wrong. 

I hear you...   :???:   :-)
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Offline AA1ZA

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Re: How to test Super Cap?
« Reply #18 on: October 22, 2018, 06:50:02 PM »

And, if you splice a 120VAC extension cord (12ga wire)  IN-BETWEEN the module and the plug end...there will be almost NO voltage drop due to combination of larger wire and very low DC current of the ISS.

Yes, thank you.   
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Offline dalecoy

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Re: How to test Super Cap?
« Reply #19 on: October 22, 2018, 08:38:35 PM »
You could test using the power supply that you are (probably) powering your Envoy with, of course.  And for a short test (an hour or so after dark), your WeatherLinkIP should continue to work OK on the Envoy batteries.

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #20 on: October 23, 2018, 12:11:47 AM »
So today after work - armed with a fresh 3V 123a battery and a Fluke 77 multi-meter - I performed the tests as suggested by rdsman earlier...

The weather station had its solar panel faced South all day, though it was overcast for some part of the day and I'm sure it must have spent a good few hours in the shade of a tree at that spot as well, i.e. so it hasn't enjoyed the best of charging conditions today.   (Unlike the day before when I actively moved it around for sunny spots all day and it still only just lasted about 30 mins after sunset).

The SIM was powered today by the new solar panel + new supercap (but no battery) and was transmitting most of the day during the sunlight hours (from about 9am until 5:30pm).  When I arrived home around 6pm, it had died already.

First I disconnected the solar panel and measured the voltage on the supercap, 0.9V.   Then I shorted the cap's legs temporarily to discharge it fully. 

Next I used crocodile leads to connect up the battery in series with the Ammeter.   For the first 40 sec or so, the current went from an initial 180 mA to a max. of 300 mA and then eventually to 0 A.   After that initial rush (which I assume has to do with charging up the supercap?) there was about a 40 sec period of no draw after which it started with repeat cycles of +/- 12 sec on, then 12 sec off.   During the on cycles it drew 20 mA which seems to correlate roughly with Davis' stated consumption of 14 mA.   Even after disconnecting all the sensors, the consumption behavior and values remained the same.

With the battery connected, the voltage across the supercap would not exceed 0.92 V. 

This seems to indicate that my SIM board probably has an issue with charging up the supercap rather than an issue of excessive consumption, right?   (I guess I must be one of the unlucky ones as Johnd had mentioned earlier). 

Your input is welcomed.   Hopefully someone can point me perhaps to a component in the charging circuitry that might be the cause of all of this, otherwise I guess my best bet is probably going to be to string DC to it...)

Dalecoy, mine is a 6322 transmitter.  I did not see an LED on it.   Should it have one?


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Offline CW2274

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Re: How to test Super Cap?
« Reply #21 on: October 23, 2018, 12:57:12 AM »
I guess my best bet is probably going to be to string DC to it...)
I'm all for DIY, but is the hassle of doing all this and that worth merely just buying a new board?

Offline AA1ZA

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Re: How to test Super Cap?
« Reply #22 on: October 23, 2018, 03:11:23 AM »
A new board costs $100+, whereas the PSU is only about $18 from what I've seen.   In my case, practically speaking, it won't be too hard to get DC wired up to the ISS. 

I guess the only reason I'm going through all this trouble is to see if I cannot save its solar / supercap functionality - I kinda like the idea of self-sufficient power...
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Offline rdsman

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Re: How to test Super Cap?
« Reply #23 on: October 23, 2018, 10:28:35 AM »
Quote
With the battery connected, the voltage across the supercap would not exceed 0.92 V.

I don't believe that the battery charges the supercap in the VP2.  I have proven this with the Vue ISS.  I think you need to look at the voltage on the supercap in full sunlight.  Can someone tell me what the IC in the red circle in this picture is?

« Last Edit: October 23, 2018, 10:30:44 AM by rdsman »
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Offline dalecoy

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Re: How to test Super Cap?
« Reply #24 on: October 23, 2018, 10:32:36 AM »
Quick notes - perhaps more later after I think about it.

The battery does NOT charge the supercap.

The LED on the transmitter only flashes in test mode - see your instruction manual.

The 12-second interval is strange - transmitter cycle is 2.5 seconds, if working correctly.

 

anything