Author Topic: Da' dreaded ISS battery "eatin'" syndrome . . . .  (Read 27612 times)

WxOwl

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Re: Da' dreaded ISS battery "eatin'" syndrome . . . .
« Reply #30 on: November 25, 2014, 12:33:05 AM »
Edouard, have you checked to see if the solar panel in the ISS is actually charging the super-cap?  I had to replace mine a couple years ago. This could explain the problem.

Regards,
Dave

Doc

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Re: Da' dreaded ISS battery "eatin'" syndrome . . . .
« Reply #31 on: November 25, 2014, 01:12:30 AM »
I was about to suggest that too, take your solar panel off and expose it to sunlight while checking the output voltage.   I don't know if the ISS you have is wireless, I'm assuming that it is.  On occasion I have run a power cord out to my ISS during times of extreme cold and powered the board through the test power plug inside the ISS housing.  I also run a small incandescent light bulb in there too for heat in the winter.  Both remote power and heat lamp are switched from the house.
Take care and have fun!  Slainte Mah!

elagache

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Today's installment (Re: ISS battery "eatin'" syndrome . . . . )
« Reply #32 on: November 25, 2014, 11:23:49 PM »
Dear Dave, Doc, and WeatherCat subscribers to my Davis station "mellar-drama."

First, the latest developments in this gripping drama . . . . .

I got back on the phone with Davis and got another guy who admitted . . . he has no idea what is going on!

He had a talk with the Davis engineers and came up with a good idea.  The battery collection must be loose. 

Just one small problem.  The battery connection cannot possibly be loose.  This is a brand new ISS board.  I checked it anyway and send the result back to Davis, so the ball is back in their court.

Edouard, have you checked to see if the solar panel in the ISS is actually charging the super-cap?  I had to replace mine a couple years ago. This could explain the problem.

Interesting.  According to this tech guy, the solar panels never fail.  He had never seen one.  I am a bit suspicious.  However, I checked the voltage on the solar panel and it is 2.5 Volts.  That is supposed to be a perfectly healthy value.  Still, that isn't a measure of current under load so I'm not convinced just yet.

I was about to suggest that too, take your solar panel off and expose it to sunlight while checking the output voltage.

That's what I did.  Do you agree Doc that a 2.5 Volt value is adequate?

That's today's installment. . . . . . . having "fun" yet? . . .  [rolleyes2]

Cheers, Edouard  [cheers1]

WxOwl

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Re: Da' dreaded ISS battery "eatin'" syndrome . . . .
« Reply #33 on: November 26, 2014, 06:31:37 PM »
So much for Davis Tech support! When I had a problem a few years back I measured open circuit voltage of about 0.8 volts and dropping down to around 0.7 when connected to the ISS. Davis Tech guy said "yeah, that sounds about right". I did not believe him. The new panel produced something around 2.5 as I recall. I just went out and measured my ISS panel voltage at 2.20 under a solid overcast sky, so 2.5volts in direct sunlight would be good. Plugging and unplugging the ISS connection showed only about a 10 millivolt change as the current required is very small once the capacitor is charged.

So, time for a new theory.

Dave

elagache

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Power switching circuit problem? (Re: ISS battery "eatin'" syndrome . . . . )
« Reply #34 on: November 26, 2014, 08:45:12 PM »
Dear Dave and WeatherCat Davis station troubleshooters,

So much for Davis Tech support!

Thanks for your own reports . . . Yes, indeed Davis instruments are very miserly about power so they can run on amazingly small amounts of power.


So, time for a new theory.

Yes, indeed and there one more piece of information that suggests an alternative.  There is a fellow on the WXForum complaining about ISS circuit boards with problems with the power switching circuitry.  There has to be some logic that switches from the solar panel, to the super capacitor, and finally to the battery if there is no other source of power.  If that logic is working incorrectly, like for example not switching to the battery early enough, then the ISS would shutdown.

It may well be the case that my long cable run to my temperature/humidity probe may require a bit more current than usually expected.  Eventually my old ISS circuit board had its super-capacitor fail.  After all, it is 5 years so.  What I have tried to replace with are newer boards with updated firmware.  I wonder if these newer boards cannot handle that additional current draw properly and are not using the battery quickly enough.

However, that gives me another sneaky idea.  It turns out that the 6382 transmitter is exactly the same circuit board as the as the ISS transmitter.  However, it has no solar panel and thus presumably never uses the super-capacitor.  I'll see if I run into problems with my temperature/humidity probe plugged into that.  If I don't, I might just buy a second one of those and use that as my ISS transmitter instead something with the solar panel.  Right now I replace the 123 battery 4 times a year on the 6382 transmitter.  If I can make my present setup work with just that change, I'll gladly pay Herb his battery commission and get rid of this super-capacitor nonsense completely.

For now I'll just keep monitoring the situation and see what happens.  I just hope nothing goes haywire during the rain event we are expected starting this weekend. 

Cheers, Edouard  [cheers1]

elagache

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Not simply the long cable. (Re: ISS battery "eatin'" syndrome . . . . )
« Reply #35 on: November 27, 2014, 11:01:00 PM »
Dear WeatherCat subscribers to my Davis station "mellar-drama."

Alas this problem insists on continuing even on Thanksgiving.  Here is what I found this afternoon when checking WeatherCat:



This rules out the assumption that it was the long cable run to the thermometer under the deck that's the problem.  Since there are two sensors having problems at once, it also seems unlikely that it is a sensor error, especially since this is now claiming that a thermometer that has never given errors before is to blame.

Definitely something really strange going on here . . . .

Oh well . . . . . .

Cheers, Edouard  [cheers1]

elagache

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Yet another battery . . (Re: ISS battery "eatin'" syndrome . . . . )
« Reply #36 on: November 28, 2014, 10:00:41 PM »
Dear WeatherCat subscribers to my Davis station "mellar-drama.",

*Sniff*, like clockwork I had another batch of sensor errors early in the morning.  Here is outage between midnight and 2am:



and here is the WeatherCat Live data report:



I gave up and "fed" the ISS another battery.  Since I have suspicion that the problem has something to do with the circuity that switches from the solar panel, to the super-capacitor, and the 123 battery, I left the solar panel disconnected.  I'm hoping that the station will switch to the 123 battery and that should give me months to come up with another solution.

Oh well, . . . . .

Cheers, Edouard

Bull Winkus

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Re: Da' dreaded ISS battery "eatin'" syndrome . . . .
« Reply #37 on: November 30, 2014, 06:07:45 PM »
It's still possible that it is interference. Weaker Xmitter current leads to weaker signal strength.

Just supposing?
 [computer]
Herb

elagache

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Shouldn't switch on and off. (Re: ISS battery "eatin'" syndrome . . . . )
« Reply #38 on: November 30, 2014, 09:53:08 PM »
Hi Herb and WeatherCat station troubleshooters,

It's still possible that it is interference. Weaker Xmitter current leads to weaker signal strength.

I believe this possibility can be ruled out because the episodes do stop after a while with no intervention on my part.  The last episode lasted from midnight to 2am.  From then on the ISS provided valid data.  That's why I believe it must have something do to with the ISS power switching circuitry.  At midnight there wasn't enough power to get data from the temperature/humidity probe and the anemometer.  Something was automatically switched at 2am so that there was now enough power.  This problem happens at a very odd battery voltage: ~3.12 Volts.  I'm guessing that is some sort of trigger point for the power switching logic.

The pattern has been so amazingly regular that I really suspect some change in the logic that Davis uses to switch from solar panel, to super-capacitor and finally to battery.  The ISS board of 5 years ago could provide power to my temperature/humidity probe under the deck.  I'm guesses that Davis tweaked the power settings to extend the battery life and now there isn't enough power for those long cable runs under some conditions when the ISS is powered by the super-capacitor.  When the ISS board finally switches to the battery, everything if fine.  That explains why there isn't enough power when the battery is indeed in the prime of its life as you had pointed out.

Cheers, Edouard

elagache

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Yet anuther battery (Re: Da' dreaded ISS battery "eatin'" syndrome . . . . )
« Reply #39 on: December 06, 2014, 10:43:41 PM »
Dear WeatherCat subscribers to my Davis station "mellar-drama."

Well it took 7 days instead of 6, but alas this morning my station did its sensor error thing:



Fortunately, the rain gauge wasn't effected by the sensor errors because we got a little more rain overnight . . .

When I got to the ISS things were slightly different.  Instead of the battery being down to 3.1 Volts, it had gone down to 2.95 Volts.  That still should have been more than enough to keep the station going, but it does show that disconnecting the solar panel has some effect on this problem.

There was one other interesting bit of evidence.  When I replaced the battery, I got a low voltage warning.  That suggests to me that the super-capacitor is completely discharged.

Nonetheless, something is very strange here.  The Davis tech I spoke with insisted that with the solar panel unplugged the ISS could run for months and Blick's station did just that.

I'm feeling like my problem has to be related to the extensions to the temperature/humidity probe cables I added.  Somehow Davis has changed either the circuitry or firmware on the ISS circuit board and under some conditions it cannot provide sufficient current to reach those sensors over that long cable.

I think I've have to swallow my pride change the configuration of my station to eliminate those extended cables.

Oh well, . . . . .

Edouard

Doc

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Re: Da' dreaded ISS battery "eatin'" syndrome . . . .
« Reply #40 on: December 08, 2014, 02:36:27 AM »
2.5 volts from the solar panel is just what I get, so I think you are OK there.  At this point, I'd be pulling all the circuit boards that are outside, including the sensors and checking everything for old solder connections.  I'd be looking at each one with a strong magnifier or microscope or I'd just resolver the thing just to be sure.  I'd check every circuit tracing on the board to make sure you don't have any cracks.  I would pull every remote sensor wire and replace the connector on all of them with fresh and newly crimped connectors.  For those I can get too, I would go into each sensor and resolver each solder point. 

Old solder can corrode over time and get covered with oxides, to get through the electricity needs more and more current to get past the oxidized solder. at the same time this puts a heavier drain on the batteries as well. 

Doc
Take care and have fun!  Slainte Mah!

elagache

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Dear Doc and WeatherCat Davis station troubleshooters,

Thanks for the advice, but I'm reasonably confident that the problem has to be those extensions I made to both temperature/humidity probes.  I've heard from both a Davis tech and a member of the WXForum that the electronics in the temperature/humidity probes are extremely sensitive to cable length and since I setup the station 5 years ago, Davis has discontinued selling the 6-conductor splicing kits and is closing out the 6-conductor extension kit.  Since the kit Davis sold was 40 feet max, and I'm running more like 100 feet . . . .   As both guys exclaimed, I'm amazed it ran for so long!

So I need another mousetrap.  I looked carefully at what other options I might have to allow me to use a unmodified Davis temperature/humidity probe.  I would like to keep my anemometer where it is, so that basically limits me to positioning the ISS no more than 100 feet from where the anemometer is now (I have to call Davis and confirm this.)  The anemometer is on the south side of the house where alas the central air conditioner condenser exhaust fan is also located.  So I need to make sure to put this temperature/humidity probe far enough away so that the thermal wake of the air conditioner won't distort the readings.

I'm going to head out and try to plan all this out, but my current hypothesis is that I should reverse my current scheme.  Instead of having a long cable from my temperature/humidity probe under the deck.  I should run all the other cables to that location under the deck and replace the sensor there.  To do that I would abandon the ISS electronics and instead use a Davis 6382 transmitter as my ISS transmitter.  According to Davis they are exactly the same board inside, just tell your console or Envoy that there is an ISS at that frequency ID, plug in your sensors and you are good to go.  Another thing I learned is that these boards have a jack for a Davis AC adapter, so I'll switch from solar power to AC power.  I'll run a extension cord to provide the power from the other end of the deck.  The other thing I would like to do is add a small electric fan.  I have a feeling the air under that deck can become stagnant if there is very little wind, and as a result, temperature values can be off because of the deck causing a thermal gradient.

I'm about to head out and see how to make this all work!  . . . . Wish me luck!

Cheers, Edouard  [cheers1]

Blicj11

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Re: Da' dreaded ISS battery "eatin'" syndrome . . . .
« Reply #42 on: December 08, 2014, 10:29:08 PM »
Ambitious plan but well thought out. You are a capable guy and if you can pull yourself away from worrying about the Buick you should be able to put it to rest.
Blick


elagache

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Speakin' of da' Devil . . . (Re: ISS battery "eatin'" syndrome . . . . )
« Reply #43 on: December 09, 2014, 09:20:54 PM »
Dear Blick and WeatherCat regular soap opera watchers, . . . . .

Ambitious plan but well thought out.

Unfortunately the weather and other "issuez" are going to force me to put this project on hold.

You are a capable guy and if you can pull yourself away from worrying about the Buick you should be able to put it to rest.

Speaking of my trusty wagon, I finally had to spill the beans of the miserable fate of my wagon on the largest forum of Buick muscle car guys.  That finally brought out the engine builder to make a public statement on the matter for the first time.  So far everything is civil, but . . . . definitely trying to thread lightly over there.

Never a dull moment . . . .

Cheers, Edouard  [cheers1]

elagache

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Appette is growing (Re: Da' dreaded ISS battery "eatin'" syndrome . . . . )
« Reply #44 on: January 06, 2015, 10:55:30 PM »
Dear WeatherCat subscribers to my Davis station "mellar-drama."

I have all the Davis parts I need to move the ISS transmitter from its present location on the end of the rain gauge to a 6382 enclosure that will be powered by an AC adapter.  Alas, trying to get all the conduits and brackets ready is taking much longer than I would have preferred.  In the meantime, the darn ISS board started giving me sensor errors when I replaced the battery yesterday!  :(

I sure hope Herb is enjoying this battery commission because he should be making a fortune on me!

Oh well, . . . .

Edouard