Is there a way to stress test crappy ni-cads that are used in decorative solar lights ?.
Its fall now, and all the solar lights are about to be put away, and I want to know which ones need replacing for the spring.

 

Is there a way to stress test crappy ni-cads that are used in decorative solar lights ?.
Its fall now, and all the solar lights are about to be put away, and I want to know which ones need replacing for the spring.

Ni-cads do not hold a charge for long. If you replace them now, most of them will be dead before you need to use them again. Do your checking and replacing in the spring.

 

Ni-cads do not hold a charge for long. If you replace them now, most of them will be dead before you need to use them again. Do your checking and replacing in the spring.

Hmm. We have quite a few solar lights out in the yard (the wife is always buying cheap little stuff -- and I mean cheap). We don't put anything inside for the winter, which means they're out there is sub-zero (°F) weather. Yet everything that's out there, including the stuff we brought from the old house six years ago (where it frequently got to -20°F in the winter) is still working fine.

My recommendation, if these are just for decorative things, is to replace them when they fail.

 

My experience with those inexpensive lights is, if half of them survive a season you’re on a winning streak.
Here in the sun belt a season is at least 8 months long, and the batteries are subjected to extreme daytime temperatures while simultaneously being vigorously charged.

 

Ni-cads do not hold a charge for long. If you replace them now, most of them will be dead before you need to use them again. Do your checking and replacing in the spring.

Thank you

 

Hmm. We have quite a few solar lights out in the yard (the wife is always buying cheap little stuff -- and I mean cheap). We don't put anything inside for the winter, which means they're out there is sub-zero (°F) weather. Yet everything that's out there, including the stuff we brought from the old house six years ago (where it frequently got to -20°F in the winter) is still working fine.

My recommendation, if these are just for decorative things, is to replace them when they fail.

Siiiiigh, thank you

 

Salvage those cheap solar garden lights. You might find a use for solar panels and bright white LEDs.

 

Do not test. Dump the NiCds; replace ALL them with Ni-metalH. While doing the transplant, solder the terminals instead of relying in springy contacts. Plug all insect and rain entry gaps too. You should get ~3 years from them.

 

Do not test. Dump the NiCds; replace ALL them with Ni-metalH. While doing the transplant, solder the terminals instead of relying in springy contacts. Plug all insect and rain entry gaps too. You should get ~3 years from them.

EXTREME CAUTION!! soldering to batteries without solder tabs welded on CAN EASILY allow heat damage to the PE end seals. So that might cause a problem. Been there and done that.

 

The cells that come with the lights are usually just 300mAh. You can occasionally find replacements with double or more that capacity very inexpensively on sale. This will provide a notable upgrade. Not worth it if you have to pay full price.

Poor connection at the battery terminals is a major failure mode for these things and, as noted, ants like to live inside. That tends to accelerate problems. I agree with the comment above that soldering to a battery terminal is potentially a problem. I got myself a tiny welding board that you can power with a car battery. With that you can attach those metal strips they use to make permanent battery connections. I can provide more detail if you're interested at all.

In my experience the cheap solar lights are limited by their panels, and so there's not a lot one can do to improve them. The higher capacity batteries help collect more power on sunny days so that they run brighter longer in to the evening, and may even help get it thru a cloudy spell. But even the bigger capacity battery will be drawn down fully in just 2 or 3 nights if they don't get a strong charge in between. The little panels aren't up to it. They do the job on sunny days but no more.

 

One of the people around here has solar-powered walkway lights, the kind that you just stick in the ground, around the perimeter of his yard (probably about 30 lights total). I was amazed how much light they put out. as well as the very pretty light pattern they display. I walk by their house when I do my walks. I'm pretty sure these are not the cheap crap you usually find, so I don't know how much they cost. I don't know if they have replaced any of them, but I know at least one of them is the same one that's been there for over five years because it has a warped case that makes a distinction distortion in the pattern. I keep meaning to stop by and inquire where they got them, but since I generally go walking around midnight, that's wouldn't be very polite (and I almost never think of it otherwise). I've never seen them not putting out full brightness, but I have no idea if I've happened to go by after several days of little or no sunshine (something that is pretty rare around here, admittedly).

 

Yes, better lights include things like charge controllers, constant current drive of the LED, a little bigger panel, better seals and so on. Oh, and a turn-off timer so that the LEDs aren't on at 3AM when almost no one would see them.

 

Yes, better lights include things like charge controllers, constant current drive of the LED, a little bigger panel, better seals and so on. Oh, and a turn-off timer so that the LEDs aren't on at 3AM when almost no one would see them.

These may have some of that, but no turn off timer (that I can tell). I'm a night-owl, so I've often been out there at any time of the night and predawn hours. The course that goes by that house was specifically chosen because nearly the entire route has streetlights along it, only crosses one street to get to it, and let's me stay on the sidewalk the entire time, so it's my night course.

 

Dump the NiCds; replace ALL them with Ni-metalH

That may not work well since NiCds are more tolerant of overcharging than NiMH types.

 

One cheap and easy action that I have found, that works for most of our solar-charged lights, is the very simple action of occasionally cleaning both the battery terminals, and the battery connection points. Just a quick rub with a shop-wipe seems to be all that it takes.
My last repair like that was yesterday. Tonight the LED light is shining brightly. Cleaning the terminals repais quite a few of those lights.
AND it is cheap and easy.
REALLY!! The terminal connections are usually materials subject to deteriorating from moisture in the air, even if there is no obvious rain leakage. And jst cleaning them is simple and easy and does not risk doing any damege, which soldering does risk. Last night I saw that a light that I had just cleaned the terminals of was working again. So terminal connection cleaning does work!!

 

I wonder if a little dielectric grease would help. I have some and don't really remember why. I think it used to be part of a standard tune-up?

 

Is there a way to stress test crappy ni-cads that are used in decorative solar lights?

Yes, get yourself one of these:
https://storefront.dc-workshop.com/...ger-analyzer-tester-nimh-nicd-aa-aaa-12-volt/

I initially balked at the price but it's sooo worth it and I have zero regrets. I gave these to family members a few years ago and for everyone this has eliminated charging headaches.

One of its capabilities is measuring the capacity of cells. I ran all my rechargeable AAs through it and that allowed me to toss maybe half of them with confidence that they were spent. I particularly like, compared to other chargers, that the four positions are fully independent.

 

Now for an answer to the initial quesyion: How to stress test those cells:Since an individual rechargable cell delivers about 1.5 volts, the cheap and fast and easy to evaluate tester is a single-cell rated flashlight bulb. THAT may be difficult to find at present.
So the alternative is a bulb intended for a TWO "D" sized cell flashlight. That bulb draws more current.
You would need to check the cells two at a time, but it should not be difficult to keep track of which cell is which, once you have located two good cells. That is about the simplest fairly good checker.

 

Is there a way to stress test crappy ni-cads that are used in decorative solar lights ?.

Since an individual rechargable cell delivers about 1.5 volts

hi

Voltage Levels by State

• • Fully Charged: A freshly charged cell reads about 1.4V to 1.45V immediately after removing it from the charger. [1]
  • Nominal / Operating: The battery stays steady at 1.2V for roughly 80% of its discharge cycle. [1]
  • Discharged (Cut-off): The lowest safe and useful voltage limit is around 1.0V per cell. [1]

 

I wonder if a little dielectric grease would help. I have some and don't really remember why. I think it used to be part of a standard tune-up?

Certainly a small bit of the grease would tend to reduce the corrosive deterioration. it would not take much, but thecleanup might be a bigger effort. So very carefu application is needed.