Dang it, bad Supercaps

[SlowModem]

I guess I am out of luck since I did not attend culinary school.

 

[Bushman]

Elsewhere I indicated that I ran regular battery level checks.

What is that supposed to mean? Transmitter battery battery status is transmitted as a single bit, a 1 or a 0, which means good or bad, so of course it happened in a "day or two". So unless you trying to say a fresh battery died in a day or two, that's all but meaningless.

When it's bright out, it will also be warmed up. So you have 3 facts.
3. Bright sun improves reception.

There are still other possible issues that could cause the problem. But you latched on to the first one you heard of, then proceeded to lambaste about it in every topic you could find a way to bring it up. The fact remains that the source of the problem is unproven and will remain so until proper on-site troubleshooting has been done. Until then, right or wrong, you are just guessing.

OK Mr  Know-it-all.  What is happening?

[C5250]

OK Mr  Know-it-all.  What is happening?

*sigh*, I'm not the one that tried to claim they knew it all. You did that when you selected a possible reason and chose to rant about it all over the place. If you hadn't done the latter, I might never have commented about it (due to the lack of information).

The fact remains that the source of the problem is unproven and will remain so until proper on-site troubleshooting has been done. Until then, right or wrong, you are just guessing.

It may be supercap problem, it may not be. Until the actual source of the problem is determined, your rants about a perceived problem are unjustified.

[Bushman]

So despite a clear pattern, solid data and prior history of a known  problem with SuperCraps (sic)  you have NO IDEA what is going on?

Regardless, a $600 buck  instrument should NOT fail after about two years.  Aren't these things supposed to be used in rough service?  Like outdoors?  In remote places?  I will stick to my belief that it is the SuperCrap and fix it when I can get back in there.  Will seriously consider some other power source (like POE) and maybe dump the part that seems to cause major failures as part of it obviously lousy design.   Or resign myself to expecting to fix them regularly.  Hopefully the next time it fails it will be in nicer weather.

[skinnysqueaky]

So is there any preventable measures one could take to enhance the longevity of the supercap?

Not really.  These failures have the indication of a bad batch of capacitors from the source manufacture.  I'll bet that they are all the same source and batch.  I saw that a lot while servicing electronics devices.   One of the most unstable components in electronics are electrolytic capacitors.

[dalecoy]

So is there any preventable measures one could take to enhance the longevity of the supercap?

Not really.  These failures have the indication of a bad batch of capacitors from the source manufacture.  I'll bet that they are all the same source and batch.  I saw that a lot while servicing electronics devices.   One of the most unstable components in electronics are electrolytic capacitors.

This has been particularly evident with LCD flat-screen monitors for computers.  During the last year, I have fixed 3 "dead" monitors by replacing a few electrolytic capacitors in the power supplies.  Of course, a $200 instrument should not fail in a couple of years.  But I would rather spend $12 to fix a monitor, than pay the repair shop $90 to do the same thing.

[johnd]

These failures have the indication of a bad batch of capacitors from the source manufacture.

Please: This is just jumping to conclusions all over again:

1. We don't yet know that the problem sparking this thread is anything to do with supercaps. It may be or it may well not be.

2. The great majority of VP2 supercap failures arose with the earlier systems, mostly 2005-6, but into 2007 to some extent. The main problem was incorrect stuffing of the boards before it was properly recognised that they needed to be stuffed correctly and carefully and then the supercap properly secured against eg mechanical shock or vibration damage.

3. There have been a smattering of supercap issues since Mfg Code A7 but much less common nowadays and spread across all sorts of Mfg dates. This just perhaps highlights the point that the supercap is not ultimately as robust a component as eg a resistor although failure is still rare nowadays. A batch problem although plausible in general is not likely in this case because of the variability in Mfg dates.

[SLOweather]

This has been particularly evident with LCD flat-screen monitors for computers.  During the last year, I have fixed 3 "dead" monitors by replacing a few electrolytic capacitors in the power supplies.  Of course, a $200 instrument should not fail in a couple of years.  But I would rather spend $12 to fix a monitor, than pay the repair shop $90 to do the same thing.

We've seen quite a few computer motherboards with blown caps, including ones from at least one major manufacturer. The back story is one of failed industrial espionage and component counterfeiting. As I recall, one company stole another's manufacturing process but missed one important ingredient in the electrolyte mix. The caps would work for a while until enough gas accumulated to cause them to leak or burst the safety seal.

There's a whole forum about this at www.badcaps.net, but the last post was over a year ago.

[twcmaster]

Sorry in advance for the rookie question, but I have read on other sites that the supercap issue has been resolved by Davis in the more recent hardware. Is this true? If I order a replacement ISS and anemometer transmitter today, is the chance of having the supercaps crap out in a couple years less than when I bought my station in 2006?

[C5250]

Davis has been making incremental steps to mitigate the problem. For instance the latest SIM board design has provision for positively securing the cap to the board. Such steps should help, but only time will tell how effective that is.

The scary part is if one reads the app notes for these Supercaps, there are cautions such as "if the cap has been dropped, don't use it". How does one insure it has never been dropped?

[twcmaster]

Ok, thanks for the info!

[wmcatty]

All in all, what do you all think the prognosis is as to the current reliability of the Supercap for Davis equipment purchased in the past 3 years?  All this talk about bad Supercaps has some of us worried about imminent failure.  

[d_l]

Some anecdotal evidence - my VP2 is over three years old and I guess the caps are fine as the batteries last over two years before I replace them preemptively.  My neighbor's VP2 is over four years old.  His first set of batteries lasted over three years.  Can't do that with bad caps.

[johnd]

All in all, what do you all think the prognosis is as to the current reliability of the Supercap for Davis equipment purchased in the past 3 years?  All this talk about bad Supercaps has some of us worried about imminent failure.  

Please see my post above, especially point [3]. (This is based on direct experience of around 1000 VP2 stations over the years.)

Of course, one of the features of the supercap problem is that typically the supercaps don't fail at all in the short term, but the fault starts to appear in the 2-4 year time frame as any latent stuffing damage starts to manifest itself. So it's really too early to be absolutely 100% sure about the 2011 vintage stations. But all the indications are that the supercap problem was largely cured by the 2008-2010 time frame and so there's absolutely no reason to suspect that 2011 stations won't be every bit as good. (But, also as above, the supercap is not a super-robust component pre-installation and it may not be surprising if the very occasional unit still shows a supercap problem after some years.)

[tomcj2]

I just received a new SuperCap from Digi-Key  ($6.09 including S&H).  I have 2 questions that I hope somebody will answer before I install it.

1)  Wold the polarity be indicated by identifying the negative lead?  The super Cap is a white can with a black stripe down one side.  On the black stripe, in white ink is " - ESHSR - ESHSR -"

Is that lead the negative one?


2) When I removed the original SuperCap last December I cut the leads very close to the can.  Would it be OK to connect the new leads to the long old ones,  or should I remove the original ones from the board?

[SLOweather]

I just received a new SuperCap from Digi-Key  ($6.09 including S&H).  I have 2 questions that I hope somebody will answer before I install it.

1)  Wold the polarity be indicated by identifying the negative lead?  The super Cap is a white can with a black stripe down one side.  On the black stripe, in white ink is " - ESHSR - ESHSR -"

Is that lead the negative one?

Yup.

2) When I removed the original SuperCap last December I cut the leads very close to the can.  Would it be OK to connect the new leads to the long old ones,  or should I remove the original ones from the board?

Soldering on to the existing, cut lead is an acceptable way to replace it. Before soldering, you may want to clip an alligator clip, or needle nose pliers on the lead between the solder joint and the board to act as a heat sink and keep conduction from softening the solder on the other side.

Be careful not to stress the leads where they exit the new cap.

[C5250]

As much as I hate to jinks anything... It's been about a year since I replaced, and doubled up, the supercaps and all stations are still working with out complaint. This is well past the 8 months a battery would last with a dead supercap. Of course there isn't much warning...