Announcement

Collapse
No announcement yet.

Solar Cell Conversion for Import Digital Calipers?

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Solar Cell Conversion for Import Digital Calipers?

    As I sat in a motel room while fleeing from the recent hurricane, I had an idea. I have a bunch of those imported digital calipers and they all need new batteries on a regular basis. Some seem to drain the battery even when not in use. So I wondered if I could add a solar cell to one or more of them to eliminate the need for a battery. I know that at least one of the high end brands does have this feature so it must be possible.

    Has anyone ever tried this? With what results? Ideas? Suggestions?
    Paul A.
    SE Texas

    Make it fit.
    You can't win and there IS a penalty for trying!

  • #2
    Wow, Paul. You had to re-locate from the hurricane?
    That is crazy. I hope your home and family are Ok.
    I talked to my cousins in Dallas, and they said they
    pretty much got nothing.

    -Doozer
    DZER

    Comment


    • #3
      He's a lot closer to the Louisiana border though. Hope your place didn't get badly hit Paul

      Comment


      • #4
        Quick look on Amazon shows rechargeable button cells with a USB plug on charger. All you need is a solar panel with a USB port.

        Comment


        • #5
          Hi Paul,
          Been wondering how you were.

          Dunno the answer to your question, but I have a Harbor Freight digital that has used exactly 2 batteries in the last 10 years. It is starting to show some age though, roughness sometimes, and need to double check the zero on startup now.

          FWIW it has been within .001 of everything else around here, so I can't complain about the $20 price.

          The Etalon vernier is far more consistent and has a better feel tho

          Comment


          • #6
            What you might run into is the fact that the battery voltage has an impact on the readings for some of the cheap capacitive calipers. All that means is that you have to re-zero it more often. I had similar musings so I I tried to run one off a rigged up super capacitor. I was able to get a button super capacitor in LR44 size. I figured that I could make a charging rack that would keep the capacitor topped off between uses. It worked but the capacitor did not hold enough charge to keep the readings steady. By this I mean that I'd measure a part at 1.256 and use the lathe to reduce the diameter by .005 inches. The next reading would be off by several thousandths. I'd re-zero the caliper and it would give me the expected reading.

            So if you do it, make sure that you use a battery that has a fairly level voltage level as it discharges.

            Dan
            At the end of the project, there is a profound difference between spare parts and left over parts.

            Location: SF East Bay.

            Comment


            • #7
              Not what you asked but.. if you can gobble up space for one ordinary AAA battery you dont need the solar cell anymore.
              15 years per battery if you use the better leakproof ones (energizer ultimate lithium)
              Location: Helsinki, Finland, Europe

              Comment


              • #8
                That's a 3 volt battery, is it not? At any rate, what if you brought a couple of leads out from the battery compartment- perhaps those leads are just visible tabs on the outside of the battery door. Then you could place the caliper in a holder and that would connect a voltage source which is just enough to keep the battery from discharging. The caliper would always have a fresh battery then- provided it isn't dying just because it's some piece of shi- garbage found in dollar stores (and some higher end stores also). If it's just going to corrode on you in short order, there would be no point in doing this. The same holds true for whatever contacts you make.

                Assuming you can do this, and don't have a corrosion problem, the next hurdle is to supply the right voltage- just barely less than the fully charged battery voltage. That way it doesn't try to charge the battery- it just keeps the voltage from dropping much below the initial voltage.

                It's not likely that any solar cell you could fit to the caliper would have enough average output to do the job- especially if you have to use a regulator- in which case you'd need about 6 volts anyway. I can see a solar cell being able to suck away more juice than your caliper already does, so even if it can't supply enough charge to hurt the battery, it will suck the battery dry during the first period of darkness. You can use a series blocking diode to mostly prevent this, but then you need even more voltage from the solar cell.

                I'm not a fan of digital calipers anyway- though to be fair I haven't used an expensive name brand. One that I have has a horrible periodic error, and I haven't found a good use for it. I guess it's a C-clamp now.
                I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                Comment


                • #9
                  Your idea sounds like a wonderful idea until you try to implement it. Instead of that route I simply went on Ebay and bought a 10 pack of the LR44. Only a couple bucks and now I don't get excited if the battery dies, I just pop in a new one.

                  https://www.ebay.com/sch/i.html?_fro...=lr44&_sacat=0

                  Comment


                  • #10
                    Originally posted by darryl View Post
                    That's a 3 volt battery, is it not?
                    Energizer ultimate lithiums (Li/FeS2) have about the same voltage as normal alkalines. (alkalines are about 1.6 volts fresh and Li/FeS2 maybe 1.8v)
                    Location: Helsinki, Finland, Europe

                    Comment


                    • #11
                      I have found that the SR44 batteries (silver oxide) last a lot longer in my cheapo HF calipers than the L44's.
                      I seem to buy a batch of ten on ebay for $5-10 every five years.

                      Comment


                      • #12
                        I suppose you could just buy a Chinese solar powered digital caliper: https://www.ebay.co.uk/itm/Accurate-...wAAOSw2QhfCJy9

                        If nothing else, it's a good proof of concept - they seem to work...

                        Ian
                        All of the gear, no idea...

                        Comment


                        • #13
                          The solution.

                          Comment


                          • #14
                            Doozer, Thanks for the concern. At one point, about two days before it hit, the projected path was aimed dead square at Beaumont, Texas, my home town. If you wait to evacuate, the roads are totally jammed and you get no where. A few years ago my daughter tried to evacuate from an area NORTH of Houston which has THREE interstate and several other highways leading north and wet. They spent the whole day in bumper-to-bumper traffic and, in the end, wound up returning home to weather out the storm. So, with a nervous wife, I/we decided to get out while the getting was good. Spent about a week in Irving, TX, a Dallas suburb.

                            Net result is everything is OK. The storm continued to change course to the east and wound up hitting land over in Louisiana, where the damage is severe in the coastal counties. It is even hard to find an uprooted tree here in town or the surrounding area. I believe the winds were never over 50 MPH. Many across the TX/LA line have no power even now and many have no home left to return to. Hurricanes are no laughing matter. We are far enough from the coast so that the storm surge is not a concern and the drainage here seems to be excellent. A few years ago we had a super wet and slow moving hurricane and my area got about 40 inches of rain - yes more than THREE FEET, more than a METER. My house was high and dry. So the only thing I now worry about is the winds. My roof is at least 20 years old and it did loose some shingles in that storm, but none from Laura. I would like to get a new roof soon, perhaps next year. I also plan to get a generator as soon as I can, probably November or December.

                            Again, thanks for the concern. We are all tired, but OK.

                            PS: I/we are hurricane pros. I was born and grew up in the New Orleans area. I worked in Miami for about 12 or 13 years and now in Beaumont. TX. I have been in many of them and been in the eye of two or three. Seen a lot of damage and flooding. In my college years I had the privilege of spending a whole week at my grandparents house outside of New Orleans chopping up fallen trees, about a half dozen of them. Took me all week to just trim off the branches then my dad and brothers joined me on the weekend to take care of the trunks: that alone was two full days of work for the three of us. No fun!



                            Originally posted by Doozer View Post
                            Wow, Paul. You had to re-locate from the hurricane?
                            That is crazy. I hope your home and family are Ok.
                            I talked to my cousins in Dallas, and they said they
                            pretty much got nothing.

                            -Doozer
                            Paul A.
                            SE Texas

                            Make it fit.
                            You can't win and there IS a penalty for trying!

                            Comment


                            • #15
                              About a 45 minute drive on I-10 to LA border. Although Jefferson County, where Beaumont is located, is at the SE corner of Texas, I-10 goes through Orange County to get there. The coastal areas of Jefferson County have more damage. Beaumont is near the NE corner of the county so we are a good distance from the Gulf Coast and among other things, I-10 itself, running east-west across the county, forms a barrier to storm surge waters. I am north of it so am pretty safe. I checked a topographic map and the history of flooding here BEFORE I purchased this house. I learned that many, many years ago after living in several coastal (east and south) areas in my life.

                              Anyway, as I said above, no visible damage at all. I do plan to get a roof inspection, but that may take some weeks with all the other work the roofers and inspectors are doing in the area now.



                              Originally posted by mattthemuppet View Post
                              He's a lot closer to the Louisiana border though. Hope your place didn't get badly hit Paul
                              Paul A.
                              SE Texas

                              Make it fit.
                              You can't win and there IS a penalty for trying!

                              Comment

                              Working...
                              X