Entropy

Relax in southern comfort on the east bank of the Mississippi. You're just around the corner from Beale Street and Sun Records. Watch the ducks, throw back a few and tell us what's on your mind.
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mediatechnology
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Re: Entropy

Post by mediatechnology » Wed Nov 14, 2018 6:30 pm

I had a similar failure with the electric space heater I use in the garage.
The crimped connections weren't made particularly well when it was new about 15 years ago.
There is a high temperature normally-closed thermostat serving as a "high limit."
Wired in parallel with the NC thermostat is a buzzer.

I didn't know the heater had a buzzer...

When the crimps failed going to the high limit thermostat the unit started buzzing very loudly.
Sort of like direct connection of a loudspeaker to 120 volts.
The last thing I was going to to do when it failed was touch it to turn it off.
So I traced the cord back and unplugged it.

Once I opened the heater up I saw bunches of questionable crimps. I soldered all of them.
It was comforting to know the unit had a buzzer and I wasn't listening to metal being welded.

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JR.
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Re: Entropy

Post by JR. » Mon Nov 19, 2018 11:55 am

OK I am tempted to take a poll... one of my two solar driveway lights is out... over the years I have replaced these before... new they are only $3-$4 ,,, Is this worth even looking at?

Years ago I wasted time re-engineering one... now I am less motivated.

any votes?

JR

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mediatechnology
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Re: Entropy

Post by mediatechnology » Mon Nov 19, 2018 6:51 pm

Is it the NiCd battery or contact problems?

I've had two that crapped out quickly after the first season.
Changed the NiCd batteries in both with "better"(?) ones I got at Home Depot and both have been running for several years.

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JR.
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Re: Entropy

Post by JR. » Mon Nov 19, 2018 9:24 pm

If that's a vote for trying to fix it, maybe tomorrow...

Yes, that is common fault...they live outdoors.

JR
[edit] I swapped out the dead as a door nail battery with another I had laying around and it appears to work... It lights up, and then the light goes out in daylight. Since these are pretty simple inside IIRC the on/off is based on the charging circuit having voltage. We'll see if it keeps working over time. I have the dead battery in a battery charger so I'll also see if it can take/hold a charge (warm but not hot).

Indeed this lamp wasn't very old, and the battery is probably the single most expensive component. They probably purchase known marginal ones (for whatever reasons). I bought two at the same time and the other one still works[/edit]

[edit2] after being partially charged (1V+) and sitting on the bench unconnected, the faulty battery self discharged to 0.01V so ding, ding, ding, we have the loser... faulty battery. I wonder how long the other one works. Both were new at same time and presumably from the same batch. [/edit]

[edit3] after dark o'clock, the lamp with the replaced battery is much much brighter than the one with its original battery, so logic suggests both original batteries were bad... I have another used battery laying around so tomorrow I will swap the other one out too.... This restores harmony to my universe as two bad batteries from the same production batch makes sense. Not good sense but is believable... A box selling 5 lamps at the store claimed a 5 year life, but AFAIK didn't guarantee that, they make crazy claims about life of the LEDs too but duh... who is going to live that long? Obviously mine were built using crapo batteries. That's one way to cut mfg cost. :roll: [/edit]

[edit4] as often happens Wayne was exactly correct. Both lamps with replacement (used) rechargeable batteries were burning bright last night when I retired for the night. I suspect my (our) experience with weak batteries is not that rare. [/edit]

[edit5] last night both lamps went dim at almost exactly the same time, so same batteries give same results. The first night the light seemed brighter longer, so we'll see how this tracks...The used batteries are really old, from my decades old digital camera I recently retired. [/edit[

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JR.
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Re: Entropy

Post by JR. » Sun Nov 25, 2018 2:12 pm

new failure... I recently bought a hose sprayer attachment to spray soapy water on my pretty roof... unfortunately the hose end sprung a pine hole leak so while trying to spray water up on my roof (in November), cold water sprays on me.

Hose is cheap but not leaking while all the ends of a few hoses are less than water tight.

I may try some repair kits.

JR

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mediatechnology
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Re: Entropy

Post by mediatechnology » Mon Nov 26, 2018 5:40 pm

Have you ever noticed how cheap batteries seem lighter (in weight) than the better ones?
The Home Depot replacements were heavier.

My UPS batteries last pretty well, about 6-8 years.
When one fails I usually by two and replace the other one I bought at the same time.
I think I have somewhere around 6 UPS units so I do these pairs in triplets.

Usually about half of them are still good, hold a charge and have fairly low internal resistance.
I have about 4 of the "good removed ones" I keep on maintenance charge that have been pulled from UPS units.
They sure are handy when you're changing out a car battery and want to keep the engine control module, clock and radio from resetting.

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JR.
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Re: Entropy

Post by JR. » Mon Nov 26, 2018 6:29 pm

mediatechnology wrote:
Mon Nov 26, 2018 5:40 pm
Have you ever noticed how cheap batteries seem lighter (in weight) than the better ones?
The Home Depot replacements were heavier.
I have yet to buy a new rechargeable battery in recent memory, and I still have two used rechargeable batteries waiting to go, albeit a couple decades old, or more.

For chuckles I weighed the bad ones... 12.5G and good ones 22G... but reading the fine print the light weight ones were only rated for 300mAh and the heavier ones were rated 1000mAh... so I guess the extra weight may be due to more actual battery inside. :o

My solar lights were looking a little puny last couple nights but that may be explainable by cloudy/overcast weather. Today was clear and sunny so we'll see if they behave better.

If they remain wimpy... I may have to break down and buy some proper batteries that were new this century. :lol:

JR


My UPS batteries last pretty well, about 6-8 years.
When one fails I usually by two and replace the other one I bought at the same time.
I think I have somewhere around 6 UPS units so I do these pairs in triplets.

Usually about half of them are still good, hold a charge and have fairly low internal resistance.
I have about 4 of the "good removed ones" I keep on maintenance charge that have been pulled from UPS units.
They sure are handy when you're changing out a car battery and want to keep the engine control module, clock and radio from resetting.

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JR.
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Re: Entropy

Post by JR. » Tue Nov 27, 2018 3:03 pm

as often happens life gives us the test, then the lesson... After researching (by trying to buy new replacements) I am learning several things. #1 many merchants present incomplete information. #2 when it comes to mAh more is not always better.

Common advice is to replace batteries each year... but $4 lamps are competitive with batteries that can cost even more.

NiCad appear to be preferred for solar lamps due to ability to tolerate more discharge cycles (1k vs 200 for NiMH).

NiCad have a memory effect from only partial discharge suggesting too many mAh provides little benefit, while modest capacity may work better being fully depleted every night. The original batteries at only 300 mAh seemed adequate, until they stopped working.

NiMH deeply discharged can self destruct so another reason to avoid the big rechargeable for this application.

Since I no longer play basket ball at night, I have no real need for late night driveway lights.

JR

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Re: Entropy

Post by JR. » Fri Nov 30, 2018 11:44 am

OK some more data... Yesterday I swapped out my driveway lamp batteries with my two other 1000mAh nicads (that old camera took 4x). I charged them before inserting, so they were topped off.... My driveway lights were still bright at 5AM this morning. :D This tells me 1000mAh is too much battery, but 20+ YO nicads may be long in the tooth. :roll:

I also used some windex on the solar charging panels this morning, one had some bird crap on it (I think the birds aim for them). So we'll see how long they light late. That said they didn't appear dirty enough to affect operation. I suspect rain keeps them reasonably clear. Another variable is that the weather warmed up a bunch and this surely affects battery capacity (60s vs 30s overnight).

I am starting to think that modern lamps probably draw less and less current with each design iteration, so the 300 mAh oem batteries were probably not that crazy...

I have mainly seen 600mAH replacement batteries so that sounds like moderate over kill...

JR

PS: As I have shared multiple times I am cheap and a pack rat... when our cold snap hit a couple weeks ago, the broken zipper on my decades old leather jacket finally drove me to purchase a new (also cheap) replacement coat. But I couldn't discard my old leather jacket despite being a little shopworn around the edges, so I also bought a replacement heavy duty zipper... I am learning that sewing leather is not easy. :roll: It's fun threading needles with 70 YO eyeballs, but the decades old (cheap) polyester thread in my packrat stash breaks too easily. I was able to push the needle through the leather with pliers. This week while food shopping I picked up some stronger (nylon) upholstery thread, and bigger eye needles :lol: . The new zipper is more than half secured, and I should probably donate the jacket to a clothing drive (after I fix it), but I may keep and use it. It is a comfortable old friend that will be warm once again. The new cheap jacket doesn't suck, it even has a hood so is warmer still when the wind if blowing.

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mediatechnology
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Re: Entropy

Post by mediatechnology » Fri Nov 30, 2018 2:09 pm

I noticed that over time the clear lenses over the solar cell yellow and craze a lot.
I don't know how much that affects output.

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